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Track your browsing activity and viewing patterns with this personal analytics dashboard that stores all data locally in your browser. The tool displays comprehensive statistics including total visits, unique pages visited, and time-based breakdowns through interactive charts showing visits by day or hour. A detailed table view shows your most visited pages and recent activity, with options to export your analytics data as JSON or clear all stored information at any time.

Create a newsletter from Simon Willison's blog posts, links, and other content by selecting content from the past several days and arranging it in your preferred order. The tool fetches data from a Datasette backup and integrates with Substack by comparing against previous newsletter RSS feeds to avoid duplicating content. Generate and copy the formatted HTML directly to your clipboard for pasting into Substack, with options to include or exclude various content types and preview the final newsletter layout.

Create cooking recipes with detailed step-by-step instructions and automatically track elapsed time and upcoming tasks during meal preparation. Load recipes from URLs or paste JSON directly, save frequently-used recipes for quick access, and optionally cook multiple recipes simultaneously with synchronized timers. The application stores all state in your browser's local storage, allowing you to pause and resume cooking sessions at any time, and includes a QR code transfer feature for continuing your cooking session on a mobile device.

Track power outages affecting the Half Moon Bay area with this interactive map displaying real-time PG&E outage data within a 15-mile radius. The application visualizes outage locations as point markers and affected areas as polygons, while displaying key statistics including the number of outages, impacted customers, and affected regions. Custom markers can be added by providing a URL parameter, and the map automatically refreshes every five minutes to ensure current outage information.

Test HTTP requests directly from your browser and inspect what response data CORS rules allow you to access. This tool lets you configure custom headers, request bodies, and HTTP methods while showing exactly which response headers and data the browser permits you to read. It's useful for debugging CORS issues, testing API endpoints, and understanding how browser security policies affect your requests.

Execute JavaScript code in a minimal MicroQuickJS sandbox running via WebAssembly, with results displayed for the final expression in your code. Code snippets are automatically saved in the URL hash, making it easy to share executable examples with others. The interface includes pre-built examples demonstrating various JavaScript techniques compatible with this ES5-like runtime environment.

Execute JavaScript code in a sandboxed QuickJS environment that runs via WebAssembly, enabling secure and fast script execution directly in the browser. Code is automatically saved to the URL hash, making it easy to share executable snippets with others. The interface includes ten built-in examples ranging from basic algorithms to practical string and array manipulation, along with keyboard shortcuts and real-time execution timing.

Track and manage two simultaneous recipes with this interactive cooking timer that displays the current step, upcoming tasks, and a complete timeline with clock times. The timer persists across browser sessions, allowing you to pause and resume your cooking progress at any point. Color-coded tags distinguish between the Cauliflower & Couscous and Chickpea Stew recipes to help you stay organized while juggling multiple dishes.

Test llm-lib, a unified JavaScript library that provides a consistent interface for multiple large language model providers including OpenAI, Anthropic Claude, and Google Gemini. Configure your provider credentials and model settings, then send messages either as complete responses or as real-time streams. The demo includes code examples showing how to integrate the library into your own projects.

Determine whether images contain birds using OpenAI's CLIP model running directly in your browser through Transformers.js. Upload images by dragging and dropping, pasting from your clipboard, or selecting files, or use your device's camera for real-time analysis. The tool processes all images locally with no data sent to external servers, and includes a webcam mode with pinch-to-zoom functionality for mobile devices.

Create custom photo print layouts for A4 pages with adjustable grid configurations, image fitting options, and portrait or landscape orientations. Users can add photos by uploading files or dragging and dropping them directly onto the page, then remove individual photos or clear the entire layout before printing. The preview displays actual print dimensions, allowing precise control over how photos will appear on the final printed output.

Convert Markdown text to HTML using GitHub's official Markdown API, with options to render standard Markdown or GitHub Flavored Markdown (GFM). The tool displays a live preview of the rendered content, automatically generates a table of contents for headings, and provides the raw HTML output for copying, while also offering cleanup options to remove GitHub-specific formatting artifacts.

Explore the CSS Grid Lanes polyfill, which brings native masonry-style layout capabilities to all browsers through the display: grid-lanes property. The demonstration showcases six practical layout patterns including photo galleries, varying column widths, newspaper-style articles with spanning elements, explicit item placement, horizontal brick layouts, and mega menus. Each example includes the relevant CSS code and interactive previews that automatically detect native browser support or activate the polyfill as needed.

Compare JSON documents side-by-side to identify additions, removals, and modifications between two versions. The tool displays differences with color-coded highlighting and provides character-level detail for string changes, making it easy to spot exactly what has changed. Preloaded examples are available to explore common use cases like configuration updates, user profile changes, and API response comparisons.

View Claude Code session .jsonl files as an interactive timeline with customizable filtering and search capabilities. This tool displays events chronologically, extracting conversation messages, tool calls, and file snapshots with formatted previews of text content, code blocks, and embedded images. Use the file picker, drag-and-drop, paste input, or URL fetch to load your session data and explore it with timezone switching, content-type filters, and easy JSON export.

Adjust indentation levels in your text with this tool that offers multiple formatting options. Add or remove spaces from the beginning of each line, strip all leading whitespace, eliminate trailing spaces, and apply or remove quote markers (>) for formatted text. Copy the processed result directly to your clipboard with a single click.

View Mozilla Codex rollout timeline events by uploading or pasting a JSONL file to explore the sequence of messages, function calls, and system events with interactive filtering and search capabilities. Each event displays its timestamp in your local timezone or UTC, with detailed views showing formatted content, tool parameters, and reasoning blocks for supported event types. Use the timeline filters to narrow results by event type, payload kind, or message role, and export specific events or concatenate user prompts for external analysis.

Test the JustHTML Python HTML5 parser directly in your browser with this interactive playground. Parse, query, and manipulate HTML using CSS selectors, pretty-print documents, extract text content, and convert HTML to Markdown—all running client-side with Pyodide. The playground supports multiple analysis modes including tree structure visualization and streaming event inspection for comprehensive HTML document exploration.

Save and manage clipboard content across multiple formats including text, HTML, RTF, and images with this clipboard backup tool. Paste any content from your clipboard to automatically create a backup that can be restored later or downloaded in its original format. All backups are stored locally in your browser using IndexedDB, giving you persistent access to your clipboard history without any external uploads or server storage.

Make Colors Transparent in PNG is an interactive tool that allows you to remove specific colors from images and export the result with transparent backgrounds. Upload or paste an image, click on any color to select it for transparency, and adjust the tolerance slider to control how many similar colors are removed. Download your processed image as a PNG file with the ability to preview the result against different background colors.

View PDF documents directly in your browser with this lightweight viewer that supports navigation, zooming, and automatic scaling. Load PDFs by entering a URL or passing one via the ?url= parameter, with support for CORS-enabled PDF sources. The viewer renders all pages with customizable zoom levels from 50% to 200%, and automatically tracks your position as you scroll through the document.

Convert GitHub issues and pull requests to markdown format by providing their URL and an optional personal access token for private repositories. The tool automatically fetches the issue details, all comments, and expands any inline code references with their actual content from the repository. Your GitHub token is securely stored in your browser's local storage for convenient access on subsequent visits.

View Mozilla Bugzilla bug reports with a streamlined interface that displays bug details, comments, and change history in an organized timeline format. Enter a bug ID, URL, or Bugzilla link to retrieve comprehensive information including status, dependencies, keywords, and all activity related to the bug. The viewer automatically fetches and displays details about related bugs referenced in dependencies and history changes, making it easy to navigate connections between issues.

Track changes across PyPI package versions by entering a package name and viewing detailed diffs between releases. This tool downloads and compares wheel files from PyPI, displaying file-by-file changes with syntax highlighting and support for custom version ranges. Share comparisons easily by copying diffs to clipboard or sharing the generated URL with version parameters.

Convert SVG images to JPEG or PNG format with customizable dimensions, padding, and background colors. The tool allows you to paste SVG code directly, upload SVG files via drag-and-drop, or load SVG images from URLs, then instantly previews the converted result and provides download and base64 embedding options. URL hashes preserve your work for easy sharing and recovery.

Search Bluesky posts using advanced filters and options to organize results by latest or top engagement. This tool requires authentication with your Bluesky account credentials and supports filtering by date range, author, mentions, language, domain, URL, and hashtags. Results can be exported as formatted markdown for easy sharing and documentation.

Browse and explore the contents of Python packages and archive files directly in your browser. Enter a PyPI package name or provide a direct URL to a .whl or .zip file, and the tool will download and display all files contained within the archive. Click on any file to view its contents in a formatted preview.

Explore how tail-recursive Python functions are transformed into optimized iterative code using the Tacopy library. Enter your recursive function in the input panel to see the automatically generated transformed version, which eliminates stack overflow risks and improves performance by converting tail calls into loops. Try the built-in examples to understand how different recursive patterns are optimized.

Convert web pages to structured content using the Jina Reader API, with support for multiple output formats including markdown, HTML, and text. The interface allows you to fetch and preview page content while optionally running AI-powered analysis through Claude to generate summaries, extract quotes, and identify key ideas from the retrieved material.

Convert terminal output into HTML by pasting colored or plain text content into the input field. The tool automatically detects and preserves formatting from RTF (rich text format) terminal output, HTML, or plain text, then generates a complete HTML document with styling that matches the original appearance. Share your converted output as a GitHub Gist or copy the HTML code directly to your clipboard.

Convert Apple Notes content to Markdown and HTML formats while preserving hyperlinks and formatting. Paste your notes into the text area to automatically generate both Markdown and HTML outputs, with a live preview of the rendered content. The tool parses RTF data from Apple Notes and provides copy buttons for easy transfer of the converted content.

Explore the mathematical and sonic relationship between frequencies through interactive demonstrations and a playable piano keyboard. This educational tool visualizes how an octave represents a 2:1 frequency ratio, allowing you to hear the harmonic connection between notes that sound identical yet exist at different pitches. Experiment with various base frequencies using the slider to understand how this fundamental musical principle scales across the entire spectrum.

Generate FFmpeg crop commands by uploading a video file and interactively defining a crop area using a draggable overlay. The tool provides both standard and iPhone-compatible FFmpeg command formats that automatically update as you adjust the crop box dimensions and position. This eliminates the need to manually calculate crop parameters for video editing workflows.

Retrieve the raw wikitext source code from Wikipedia articles by searching for a page title or pasting a direct article URL. The tool features autocomplete suggestions while typing search queries and allows you to easily copy the fetched wikitext to your clipboard for further editing or analysis. URL parameters are preserved, enabling you to share links that automatically load specific Wikipedia articles.

Analyze written text to identify words and phrases that can be removed without changing meaning or grammatical correctness. This tool uses Claude to apply the editing principle "Omit needless words" from Strunk & White's classic style guide, marking removable content like filler words, redundant modifiers, and wordy phrases. Choose from multiple Claude models and customize the system prompt to refine the editing criteria for your specific needs.

View Bluesky thread conversations with nested reply hierarchies and chronological sorting options. This viewer fetches posts from public Bluesky APIs and displays them with color-coded depth levels, embedded media support, and interactive features like quoted post previews and image galleries. Users can toggle between thread view (showing reply nesting) and chronological view (most recent first), with the ability to hide non-author replies in thread mode for easier navigation through long conversations.

Search for quote posts on Bluesky by entering a post URL to discover all responses that quote the original post. The tool fetches and displays these quotes with options to sort by likes, recency, or oldest first, and provides direct links to view each quote on Bluesky or explore its thread context. A color-coded depth indicator helps visualize the conversation hierarchy.

Convert text to The New Yorker's distinctive typographic style, automatically applying diacritical marks like diaereses (coöperate, naïve), converting straight quotes to curly quotes, replacing hyphens with em dashes, and transforming ellipses into proper typographic characters. Paste your text into the input field to instantly see the refined version, then copy the converted result with a single click.

View liked posts from any Bluesky user by entering their profile URL, handle, or DID. This application fetches and displays a user's favorite posts with full post details including text, images, and engagement metrics, allowing you to browse and export the content in multiple formats. Simply enter a Bluesky profile identifier and the viewer will retrieve up to 200 of their most recent likes with the ability to load additional posts.

Extract hyperlinks from pasted web content and export them in multiple formats including HTML, Markdown, and plain text. The tool automatically detects and removes duplicate links while displaying each link's title and URL for easy verification. Copy extracted links in your preferred format with a single click.

Compare two blocks of text to identify character-level differences between them. This tool uses a dynamic programming algorithm to compute the longest common subsequence and highlights removed text in red and added text in green for easy visualization of changes. The results are displayed character-by-character in a dedicated output section that clearly indicates what was deleted from the original text and what was inserted in the modified version.

Analyze images using the Google Gemini API and visualize detected objects as bounding boxes or points overlaid on the original image with coordinate grid lines. The tool supports multiple Gemini model versions and can extract either bounding box coordinates in normalized format or point locations with labels, displaying the results alongside a detailed visualization canvas. Store your API key locally for convenient access across multiple sessions.

Check XML documents for well-formedness by pasting content into the input area and clicking the validate button. The tool parses the XML and displays any syntax errors with precise line and column information, highlighting the problematic line in the code view below.

Extract and identify all emojis from text by pasting or typing into the input field, and instantly view their names and Unicode codepoint values. The tool uses a comprehensive emoji detection regex pattern combined with a Unicode emoji dataset to recognize a wide variety of emoji characters, including skin tone variants and zero-width joiner sequences. Results are displayed in real-time, showing each unique emoji found along with its standardized name and corresponding Unicode representation.

Extract alternative text and image URLs from rich text content pasted into this tool. Simply paste content from web pages, and the tool automatically detects embedded images, displays them alongside their alt text descriptions, and provides copy buttons for convenient access to both the alt text and image URLs. This utility is particularly useful for accessibility audits, content analysis, and archiving image metadata.

Convert between special characters and their HTML entity representations with this bidirectional encoding tool. Select between Escape mode to convert characters like <, >, &, and quotes into their corresponding HTML entities, or Unescape mode to decode HTML entities back into readable characters. The tool supports named entities, decimal numeric references, and hexadecimal numeric references, with real-time conversion displayed in the output field.

Monitor your GitHub API usage with this rate limit checker tool. Authenticate with your GitHub account to view detailed information about your remaining API calls across different resource types, including visual progress indicators and reset times. The tool displays usage statistics and alerts you when your rate limits are running low.

Count tokens in your Claude API requests using this web-based token counter tool. Enter a system prompt and user message, optionally attach images or PDF documents, and receive detailed token usage information for billing and optimization purposes. The tool securely stores your API key locally and communicates directly with the Anthropic API to provide accurate token counts for your exact message content.

Interact with a MicroPython device via the Web Serial API to execute Python commands in real-time through a browser-based REPL interface. This tool enables direct communication with compatible microcontroller boards, allowing users to run Python code, query system information, and manage files without requiring terminal software or drivers. The interface provides quick-access buttons for common operations like listing files, checking CPU frequency, and monitoring available memory.

Create and edit 24×24 pixel icons with an intuitive browser-based editor featuring a live grid canvas, color picker, and emoji starter templates. Design your icons by clicking pixels directly on the canvas, customize colors using the preset palette or custom hex input, and optionally start with common emojis or custom characters that are automatically converted to pixelated artwork. Your work is automatically saved to the URL, allowing you to bookmark or share your designs without any backend storage requirements, and you can download your finished icon as a PNG file when complete.

Explore GitHub's GraphQL API using an interactive query interface that requires authentication via a personal access token. Enter your GitHub token to connect and start writing, executing, and testing GraphQL queries against GitHub's data in real-time. The explorer provides syntax highlighting, query validation, and response inspection capabilities within an embedded GraphiQL environment.

Count lines of code in software projects by uploading files, pasting code snippets, or analyzing public GitHub repositories using the classic SLOCCount algorithm compiled to WebAssembly. The tool analyzes code in multiple programming languages and provides detailed breakdowns by language along with cost and effort estimates based on the COCOMO software engineering model. Customize the salary and overhead multipliers to adjust the estimates based on your specific context.

Interact with OpenAI's GPT-4o audio models to generate spoken responses to your prompts with customizable system instructions and voice selection. The application processes your input through the OpenAI API, retrieves the generated audio and transcript, and provides playback controls along with the full API response data. You can save responses as GitHub Gists and download the audio files for offline use.

Create perfectly sized social media cards by uploading an image, selecting your desired aspect ratio, and adjusting the crop with zoom controls. The tool automatically centers your image on a customizable background color and provides a preview before downloading your final card at optimal dimensions for Twitter, Facebook, Instagram, Substack, and other platforms.

Explore a product catalog with interactive item details displayed in a smooth side panel modal. Click any product card to view comprehensive information including category, price, and description, with the option to toggle between modal and non-modal dialog behavior. The interface includes a feedback form within the side panel, allowing users to submit comments about products with a seamless animated experience.

Remove query parameters and tracking data from URLs with this Query String Stripper tool. Paste any URL to instantly extract the base address by stripping away everything after the question mark, then copy the cleaned result to your clipboard with a single click. This utility is helpful for sharing clean URLs, removing analytics parameters, or simplifying web addresses for documentation purposes.

Extract all strings from JSON data that exceed 20 characters in length or contain line breaks. This tool is useful for identifying longer text content within complex JSON structures for review, localization, or documentation purposes. Simply paste JSON into the textarea to automatically display matching strings along with their object paths, and use the copy button to quickly transfer any string to your clipboard.

Analyze and visualize AI deep research transcripts with this interactive viewer that displays the complete research workflow including reasoning steps, web searches, visited pages, and code executions. Load transcripts from GitHub Gists, paste JSON directly, or view example data to explore how the AI model conducted research and arrived at its final conclusions. The viewer provides statistical summaries and a chronological timeline showing the model's thinking process, search queries, page visits, and computational steps in an easy-to-read format.

Convert Rich Text Format (RTF) documents to HTML with preserved formatting, colors, and styling. Paste RTF content from your clipboard to automatically extract the color table and convert text formatting including bold styling, text colors, and background colors into inline HTML styles. The converter displays the raw RTF data, generated HTML code, and a live preview of the formatted output all in one interface.

Explore OpenAI's prompt caching feature by testing different prompt structures and observing cache hit rates across multiple requests. This interactive playground lets you compose system instructions, document context, and user questions, then send them to the Chat Completions or Responses API to track how cached tokens reduce costs and improve performance. Load pre-built scenarios to compare caching behavior—such as sending identical instructions with different questions to see cache hits, or swapping documents while keeping instructions static to measure prefix reuse.

Capture images from your device's camera and generate haiku poetry inspired by what you photograph using Claude's vision capabilities. Press the camera button to take a photo, and the AI will compose an original haiku based on the image content. The app stores your Anthropic API key locally for convenience and supports switching between front and rear-facing cameras on devices with multiple camera options.

Convert formatted text from rich text editors or web pages directly into clean Markdown syntax. This tool accepts pasted content with bold, italic, links, lists, and paragraph breaks, then automatically converts the underlying HTML to properly formatted Markdown that can be copied with a single click. It works offline in your browser without requiring any external dependencies or frameworks.

Render DOT graph files into visual diagrams directly in your browser. Paste your DOT syntax into the textarea and the graph will automatically render as an SVG visualization, with live updates as you edit. Share your graphs by copying the URL, which encodes your DOT content in the fragment identifier.

Analyze Hacker News stories by searching for multiple terms across a custom time range and visualize the results as an interactive histogram. The tool fetches monthly hit counts from the Hacker News API for each search term, displaying data in a color-coded bar chart, sortable table, and exportable JSON format. Click any bar to view the actual stories matching that term within that month's date range.

Monitor keyboard input in real-time with this interactive keyboard debugger that displays pressed keys and their corresponding key codes. Press any keys on your keyboard to see them appear with visual feedback, including support for simultaneous multi-key presses and special key representations. This tool is useful for testing keyboard functionality, debugging input handling, and understanding key event properties like key name, code, and keyCode values.

Run Python code directly in your browser using MicroPython compiled to WebAssembly. Enter Python code in the editor and click Run to execute it instantly, or use the Tests button to verify core functionality including arithmetic, state persistence, exception handling, and standard library features. The entire MicroPython runtime is loaded from a CDN, requiring no local installation or server-side processing.

Execute NumPy vector and matrix operations directly in your browser using an interactive lab powered by Pyodide. Work through five hands-on exercises covering elementwise operations, dot products, matrix multiplication, broadcasting, and indexing, then experiment freely in the playground sandbox with instant Python output.

Draw pixel art for e-ink badge displays with this web-based canvas editor supporting multiple brush sizes, undo/redo functionality, and real-time black-and-white preview. Export your designs as PNG files or transfer them directly to Badger2040 devices running MicroPython via Web Serial. The editor maintains device-native resolution while offering adjustable zoom levels and includes features like grid overlay, background image loading, and URL-based bookmarking for saving your work.

Look up GitHub user account information by entering a username to retrieve the numeric Account ID and account creation date through the public GitHub API. The tool displays the user's profile link, avatar, and formatted timestamps, along with request latency information. Unauthenticated requests are subject to GitHub's rate limits, which may block further lookups after a certain number of queries.

Execute Python code directly in your browser with Pyodide, a WebAssembly-based Python runtime. This demo loads pandas, numpy, and matplotlib in the client to generate a bar chart from sample data and display it as a rendered image—no server required. The first run may take a few seconds as the necessary libraries are downloaded from CDN, but subsequent executions run instantly from your browser's cache.

View AI adoption trends across different firm sizes by analyzing survey data on artificial intelligence usage in the workplace. This page runs a Python analysis using Pyodide to fetch employment survey data, calculate six-survey rolling averages, and generate an interactive visualization showing adoption rates by company size from November 2023 through August 2025. Download the resulting chart as PNG or SVG for further use or presentation.

Compare images at different sizes and quality levels by uploading a photo, defining a crop area, and generating multiple preview versions with varying dimensions and compression settings. The tool displays file sizes for each variant and allows interactive toggling between normal and full-width viewing modes, as well as direct downloads. Transparency detection automatically reveals a background color picker when needed for images with alpha channels.

Extract text from PDF documents and images using optical character recognition (OCR) directly in your browser. The tool leverages Tesseract.js for text recognition and PDF.js to handle multi-page PDF files, supporting multiple languages and file formats including JPEG, PNG, and GIF. All processing occurs locally in your browser with no files being transmitted to external servers.

Navigate the treacherous single-track lanes of rural Devon in this interactive driving simulator, where you must manage your sanity while encountering cyclists, tractors, caravans, and other obstacles. Each encounter presents a unique challenge requiring a dice roll to succeed, with your choices affecting both your progress and mental state as you attempt to travel increasingly longer distances. The game combines humor, strategy, and unpredictable encounters to test whether you can survive the quirky chaos of England's countryside roads.

Retrieve and view recent comments from a Hacker News user by entering their username and fetching up to 1,000 of their most recent comments. The tool displays each comment with its date, associated story title, thread link, comment link, and full text in an easily readable format. You can copy all the retrieved comments to your clipboard with a single click.

Calculate and rescale percentage values in real time with this interactive tool. Enter up to four percentages and optionally mark any as ignored to exclude them from the recalculation, which automatically normalizes the remaining active percentages to sum to 100%. The interface displays both the original values and their recalculated equivalents, making it useful for adjusting weighted distributions or normalizing survey responses.

Test the Web Speech API's speech synthesis capabilities by entering text and configuring voice parameters such as rate, pitch, and volume. The application provides a selection of available system voices and displays real-time status updates as text is being spoken. Users can adjust synthesis settings and stop playback at any time using the intuitive control interface.

Learn the difference between bullish and bearish market sentiment through an interactive visual guide featuring animated bull and bear characters. The page uses intuitive animal metaphors—bulls thrust their horns upward to represent rising markets and optimism, while bears swipe downward to represent falling markets and pessimism. A built-in quiz feature helps reinforce these concepts with randomized questions about market terminology.

Browse the Open Sauce 2025 conference schedule with sessions organized by day, including speaker information, session duration, location, and detailed descriptions. Users can search for specific sessions across all three conference days (July 18-20, 2025) and download the entire schedule as an ICS calendar file for integration with their calendar applications. The interface displays current and upcoming sessions in Pacific Time to help attendees plan their conference experience.

Compress and optimize image files by uploading them to this web-based tool that applies adjustable JPEG quality settings to reduce file size. The interface allows users to compare the original and optimized versions side-by-side by toggling between views or pressing and holding the image, while providing real-time compression statistics and the ability to download the optimized file or copy its data URI for embedding in code.

Browse the latest Hacker News stories with customizable content filtering to exclude topics of your choice. Enter comma-separated terms to filter out posts matching those keywords across titles, URLs, and descriptions, and refresh the feed to load the newest stories. Your filter preferences are automatically saved in your browser for future visits.

Interact with Chrome's built-in language model API through this web-based playground interface. The application allows users to check model availability, download the model if needed, and execute text prompts to generate responses directly in the browser. A persistent history feature maintains records of previous prompts and responses for easy reference.

Calculate the time between two dates with detailed breakdowns and visual representations. This tool displays the total number of days, weeks, business days, and weekend days spanning your selected date range, along with a visual timeline showing where the dates fall relative to today. Use the calculation method options to focus on specific day types such as business days or weekends only.

Chat with Google's Gemini AI models directly in your browser using this interactive chat application. Simply enter your Gemini API key (stored locally for convenience) and select from multiple available models including Gemini 2.5 Flash, Pro, and various other versions to power your conversations. The app displays real-time streaming responses, tracks API usage metrics, and measures response duration to help you monitor your interactions.

Use the Gemini API to analyze images and generate segmentation masks with visual overlays. Upload an image and provide a prompt describing what you want to segment, then the application displays bounding boxes and mask visualizations directly on the image canvas. Token usage metrics are provided for each API call, and you can choose from various Gemini model versions including thinking and non-thinking variants.

Convert JSON transcripts from audio into formatted Markdown with speaker names and timestamps. This tool automatically processes JSON data containing speaker names, text, and timestamp information, formatting them into readable Markdown output that can be easily copied and pasted elsewhere. The tool includes instructions for generating the required JSON format using the LLM command-line tool with audio files.

Calculate reading time estimates for any text by pasting or typing content into the input area. The tool displays real-time statistics including word count, character count, and estimated reading duration based on an average reading speed of 230 words per minute. The reading time adjusts dynamically, showing minutes for shorter texts and hours plus minutes for longer content.

Send chat messages that synchronize instantly across multiple browser tabs using the Broadcast Channel API. Each tab displays messages sent from other tabs with a sync indicator, allowing real-time communication without requiring a backend server. Open multiple tabs of this page to see messages propagate automatically across all instances.

Calculate file transfer duration by entering the file size and transfer speed with their respective units. The calculator automatically converts between different measurement units (GB, MB, TB for file size; Mbps, MB/s, KB/s for speed) and displays the estimated transfer time in an easily readable format. Results include a detailed breakdown showing days, hours, minutes, and seconds alongside the calculation parameters.

Experiment with CSS Flexbox properties in real-time using this interactive playground. Adjust container properties like flex-direction, justify-content, and align-items while watching the layout change instantly, then select individual items to customize their flex-grow, flex-shrink, flex-basis, and alignment settings. The dynamically generated CSS code output shows the exact syntax needed to recreate your layout, making it an effective learning tool for mastering flexbox concepts.

Download and view the complete conference schedule for May 22, 2025, in iCalendar format. This page provides access to all 25 events from the San Francisco conference, including keynotes, technical sessions, workshops, and office hours, which can be imported directly into your calendar application. A live preview of the ICS file contents is displayed below the download button for reference.

Create annotated presentation slides with alt text and markdown notes. Upload your slide images, add accessibility descriptions and annotations with markdown support, then generate HTML output using customizable templates. The tool automatically saves your work and includes optional OCR functionality to extract text from slides.

Parse and visualize JSON responses from the Google Gemini image generation API, extracting and displaying generated images, text content, and usage metadata in a formatted layout. The tool supports direct JSON input through paste or by loading example datasets, making it useful for testing and inspecting Gemini API outputs including model version information and token usage statistics.

Write HTML code directly in the editor pane and see the rendered output update in real-time in the preview pane. The editor supports live preview with debounced updates to prevent excessive rendering, and includes a copy button to save your HTML code to the clipboard. On mobile devices, toggle between the editor and preview views using the dedicated button in the toolbar.

Visualize bounding boxes and PNG masks from JSON data with support for multiple coordinate system origins. This tool accepts JSON input containing box coordinates and base64-encoded mask images, then displays them overlaid on an interactive canvas with real-time coordinate transformation. The visualization includes detailed information about each item's original and transformed coordinates based on the selected origin point.

Decode base64-encoded gzip data to retrieve the original decompressed content. Paste your base64 string into the input field and click the Decode button to process the data. The decoder handles the conversion from base64 format and gzip decompression in sequence, displaying the result or providing detailed error messages if the input is invalid.

Export Hacker News discussion threads in a formatted, hierarchical structure by providing a post ID or direct link to the thread. The tool fetches all comments from the specified post and organizes them with numbered paths that show the conversation structure, making it easy to read and copy the entire discussion for archival or sharing purposes.

Explore an interactive footnote system that enhances document reading by displaying footnote content in contextual popups when you hover over or click footnote references. The implementation uses semantic HTML with proper ARIA roles for accessibility, combined with CSS styling and JavaScript to position popups dynamically based on viewport constraints. This approach maintains traditional navigation between footnotes and their references while providing a modern, user-friendly experience that works across both desktop and mobile devices.

Convert rich text content from clipboard into clean, filtered HTML containing only semantic elements like paragraphs, headings, lists, links, and text formatting. Paste formatted content into the editable area to automatically extract and sanitize the HTML, removing unsupported tags and attributes while preserving the document structure and links. The cleaned HTML is displayed in a code editor and rendered in a live preview, with options to copy the code or clear all content.

Explore American Community Survey demographic and social data through an interactive search and visualization tool. Select geographies such as cities, counties, or states alongside census topics like income, education, or housing to retrieve detailed population estimates with margin of error values. The application presents census data in both tabular and chart formats, making it easy to compare statistics across multiple locations and time periods using the Census Reporter API.

Explore demographic and economic data from the US Census American Community Survey using the Census Reporter API. This tool allows you to search for specific geographic locations and data tables, then retrieve detailed census statistics including estimates and margins of error. Simply select a geography and one or more data tables to view comprehensive statistical breakdowns organized by column with their corresponding uncertainty measurements.

Experiment with passkey registration and authentication using the WebAuthn API in your browser. This demo allows you to create passkey credentials, authenticate with them, and inspect the underlying protocol responses and data. Stored credentials are maintained locally in your browser's storage, making this a fully client-side implementation for learning how modern passwordless authentication works.

Track time with Lightning Timer, a full-screen countdown application that displays elapsed seconds in large, easy-to-read format. Click the timer display to start, pause, or reset the countdown, and access the settings icon to configure the total duration and optional warning threshold that triggers a visual color change. The timer supports URL-based configuration for quick setup and displays the remaining time in both the page and browser title bar.

Format and visualize incomplete or truncated JSON data with automatic live formatting as you type. This tool handles malformed JSON structures by applying consistent indentation and proper spacing, making it easier to read and understand partial JSON snippets. The formatted output can be copied to the clipboard with a single click, and example data is available to test the functionality.

Inspect and analyze clipboard data by pasting content into this viewer to see all available formats and their corresponding values. The tool displays text, HTML, images, and file information in an organized format, with special handling for image previews and multi-file pastes. This is useful for debugging clipboard operations and understanding what data formats are available when copying and pasting content across applications.

Display and edit images with an interactive cropping interface for creating avatars or profile pictures. Users can select images by clicking, dragging and dropping files, or pasting from the clipboard, then crop them to a specified aspect ratio using resizable handles. The final cropped image is automatically exported as a JPEG data URL and can be synced to a designated form input field for seamless integration with web forms.

Check the storage size of Hugging Face machine learning models by entering a model URL or repository path. The tool queries the Hugging Face API to retrieve the total storage used by the specified model and displays the result in a human-readable format (MB or GB). Models can be looked up using either their full Hugging Face URL or their model identifier in the format username/model-name.

Display and manage multiple filter conditions using an interactive badge interface with keyboard navigation support. Each filter badge displays a column name, operator, and value that can be edited individually, with options to add or remove filters as needed. The component provides full accessibility through keyboard shortcuts, focus management, and ARIA labels for screen reader users.

Track the progress of the current U.S. presidential term with real-time statistics and a visual progress bar. The page displays elapsed and remaining days, percentage completion, and specific metrics related to the midterm election cycle scheduled for November 3, 2026. Information updates automatically to provide current data on the four-year term that began on January 20, 2025.

Explore wildlife observations on an interactive map by searching for any species and viewing recent sightings from the iNaturalist community. The map displays geotagged observations within a customizable time range, with clustering for easy navigation across regions and detailed information for each sighting including photos, dates, and observer information. Share specific searches through URL bookmarks to quickly return to previous species and time period filters.

Extract a subset of Swagger/OpenAPI definitions by selecting specific API endpoints and their dependencies. This tool parses a Swagger JSON document, displays all available paths and methods in an interactive checklist, and generates a filtered JSON output containing only the selected endpoints along with any referenced schema definitions they require. The generated subset can be copied to the clipboard for use in other applications or documentation.

Calculate token usage across your Claude and other LLM API calls by pasting YAML output from the LLM tool's llm logs -su command. The calculator automatically groups token consumption by model and displays total input and output tokens for each. This helps you track and analyze API usage patterns across multiple conversations and model versions.

Learn how CSS text wrapping properties control how text flows within containers, including word-wrap, word-break, white-space, text-overflow, hyphens, line-break, and text-wrap. This guide provides interactive demonstrations of each property's behavior, detailed explanations of their values, and current browser compatibility information to help you choose the right approach for your text layout needs.

Track California's Daylight Saving Time changes with this tool designed for Pacific Time users. The page displays the most recent clock change, calculates the next scheduled adjustment, and provides helpful context about how the time shift affects daily routines and pet schedules. It automatically detects your timezone and updates information throughout the day to keep you informed about upcoming or recent DST transitions.

Extract HTML code from formatted text by pasting rich content into this tool, which automatically captures and displays the underlying HTML markup. The tool provides both the raw HTML code for editing and a live preview of how the formatted content renders. Use the copy button to quickly transfer the extracted HTML to your clipboard, or clear the interface to process new content.

Encrypt and decrypt messages using a passphrase with this web application that leverages modern browser cryptography APIs. The tool generates a secure shareable link containing an encrypted message that can only be decrypted with the correct passphrase, making it useful for sending sensitive information. All encryption and decryption operations occur entirely in the browser, ensuring your data never leaves your device.

Create JSON schemas interactively with this builder tool that allows you to define properties, set data types, and configure nested objects through an intuitive form interface. The generated schema is displayed in real-time and can be copied to your clipboard for use in your applications. Your schema is automatically saved in the URL, making it easy to share or revisit your work later.

Convert a compact schema definition language into JSON schema format in real-time. This tool accepts a concise DSL where you specify field names, types (str, int, float, bool), and optional descriptions, then automatically generates the corresponding JSON schema. The converter supports both object schemas and array item schemas through the "Array items schema" option.

Parse Pipfile.lock files to extract Python package dependencies and convert them into multiple formats for easy management and sharing. The tool automatically extracts package names and versions from the lock file and displays them in both Pipfile and requirements.txt formats, with one-click copying functionality for each output format.

Track word and character counts across multiple writing sections with automatic saving to browser storage. Each section displays real-time statistics as you type, and content persists between sessions. Add or remove writing sections as needed to organize different pieces of text.

Analyze and explain SQLite queries using APSW by entering SQL code and executing it in an in-browser Python environment. The tool provides detailed query analysis including execution plans, expanded SQL, and query information to help understand how SQLite processes your queries. Optional setup SQL can be run before the main query to create tables or initialize data, and parameterized queries are supported through labeled input fields.

Format and beautify SQL queries with customizable styling options. This tool supports multiple SQL dialects including SQLite, PostgreSQL, and MySQL, allowing you to control indentation width, keyword capitalization, and indentation style. The formatted output can be easily copied to your clipboard with a single click.

Render Claude API responses with proper citation formatting by pasting JSON output into this tool. The tool parses the response structure and displays text content alongside blockquote-formatted citations, making it easy to review how Claude has sourced and attributed information. An embedded iframe renderer safely displays the formatted output with styling that highlights cited passages.

Convert serialized PHP data to JSON format for easy viewing and manipulation. Paste your PHP serialized string into the input field to automatically parse and display the equivalent JSON output. Use the copy button to quickly transfer the JSON to your clipboard.

Explore live region notifications with this interactive accessibility demo that allows you to test how screen readers announce dynamic content updates. The page provides instructions for testing with VoiceOver on macOS and iOS, plus interactive controls to trigger notifications with different aria-live settings (assertive or polite) to observe how screen readers prioritize and announce content changes.

View and resolve Bluesky handles to their corresponding Decentralized Identifiers (DIDs) using the AT Protocol API. Enter a Bluesky handle in the format username.bsky.social to retrieve the associated DID, which serves as a unique identifier for accounts on the Bluesky network. This tool provides a simple interface for looking up handle-to-DID mappings through Bluesky's public resolver endpoint.

Monitor real-time Bluesky feed data by connecting to the Bluesky Jetstream WebSocket service and viewing incoming posts and events. Send custom JSON messages to filter the feed by collection type, specific user DIDs, or other parameters, with all activity logged in the output panel for debugging and inspection. Use the provided keyboard shortcut (Ctrl/Cmd + Enter) to quickly send configuration updates to the WebSocket connection.

Parse and visualize YAML files in an interactive tree format with collapsible sections for easy navigation of nested data structures. Enter YAML content directly or load from a URL, then explore the data by expanding and collapsing individual elements. The tool preserves your navigation state in the URL, allowing you to share links with specific sections already expanded.

Establish real-time audio conversations with OpenAI's GPT-4o model using WebRTC technology. This interface allows you to select from multiple voice options and monitors detailed token usage and costs for each interaction and across your entire session. All API tokens are stored locally in your browser for convenience.

Play audio responses generated by OpenAI's GPT-4 with audio preview model by providing a GitHub Gist URL containing the API response JSON. The player extracts base64-encoded WAV audio data from the Gist, converts it to playable format, and displays the associated transcript. You can listen to the audio directly in the browser or download it as a WAV file.

Convert JSON data into multiple YAML formats with a single paste. The tool generates three output variations—block style for readability, flow style for compactness, and quoted strings style for explicit formatting—allowing you to choose the best format for your needs. Each output can be copied to your clipboard with a single click.

Process HTML content to automatically generate unique IDs for all header elements and create a table of contents with anchor links. This tool is useful for adding navigation functionality to static HTML pages or preparing content for documentation systems that require header identification. Simply paste your HTML and provide the page URL, then the processor will output the modified HTML and a formatted list of clickable header links.

Analyze your writing for common style issues by pasting text into this tool, which detects weasel words (such as "very" and "quite"), passive voice constructions, and duplicate consecutive words. The analyzer provides contextual snippets for each issue found, helping you identify areas where your writing could be more direct and concise. This tool is adapted from shell scripts by Matt Might and updates results in real-time as you type.

Plan meetings across multiple time zones by selecting two locations and viewing their local times side-by-side. The comparison table displays 48 consecutive hours of UTC times with corresponding local times for each timezone, making it easy to identify overlapping working hours. Your timezone selections are automatically saved in the URL for convenient sharing and bookmarking.

Prompts.js is a lightweight JavaScript library that provides modal dialog functionality for creating alert, confirm, and prompt interactions in web applications. The library enables developers to display user-facing dialogs with async/await syntax, making it easy to handle user responses in a clean, readable manner. This demo page allows you to test the three core dialog types and view the results of user interactions.

Convert Unix timestamps to human-readable dates and times with this tool. Enter a Unix timestamp (in seconds or milliseconds) to instantly view the corresponding date and time in both UTC and your local timezone. The converter automatically handles both 10-digit and 13-digit timestamps, making it easy to work with timestamps from various sources and systems.

View Bluesky social media timelines by authenticating with your account credentials and retrieving live feed data. The application automatically refreshes your timeline at regular intervals while displaying posts with author information, timestamps, and full JSON response data for advanced inspection. Credentials are securely stored locally in your browser for convenient access during future sessions.

Explore API endpoints and view their responses in real-time using this interactive tool. The interface uses sandboxed iframes with postMessage communication to safely fetch and display JSON data from remote APIs. Enter any API URL and submit to see the formatted response displayed directly in the browser.

Draw bounding boxes on images using an interactive cropping tool powered by CropperJS. Load an image by pasting, dragging and dropping, or selecting a file, then click and drag to create a box around your region of interest. The tool automatically outputs normalized coordinates as percentages of the image dimensions in a format ready for command-line use.

View Mozilla's browser compatibility data to track when web APIs were first supported across different browsers. Search for any API by name to see a chronological timeline of support additions, including release dates and version numbers for each browser. The interface also displays relevant MDN documentation links, specification URLs, and status indicators to help developers understand the maturity and adoption timeline of web platform features.

Test and explore HTML, CSS, and JavaScript code in a sandboxed iframe environment with configurable security restrictions. The left panel provides a code editor for writing HTML content, while the right panel displays a live preview with customizable sandbox attributes that control what the iframe can access and execute. Use the checkboxes to enable or disable specific permissions like scripts, forms, popups, and same-origin access to understand how sandbox restrictions affect web content behavior.

Display an animated rainbow gradient border effect around a centered box with interactive controls. The page features a dark theme with a glowing, color-shifting border that can be toggled on and off using the provided button. The animation combines gradient shifting and pulsing effects to create a dynamic, eye-catching visual presentation.

View Mozilla Bugzilla bug reports directly from your terminal using this LLM plugin for Google's Gemini API. The plugin enables seamless integration between your command-line workflow and Bugzilla's bug tracking system, allowing you to query and retrieve bug information without leaving your terminal environment. This tool is particularly useful for developers who want to incorporate bug data into their LLM-powered workflows and automation scripts.

Embed SVG images directly into HTML using base64 data URIs, which eliminates the need for separate image files and reduces HTTP requests. This demo showcases three different SVG examples encoded in base64 format and displayed through standard image tags, with included JavaScript that safely decodes and displays the underlying SVG source code. When SVGs are embedded this way as images, any potentially unsafe JavaScript or interactive elements within them are automatically ignored by the browser, providing a secure method for inline image delivery.

View SVG content being progressively rendered character by character over a specified duration. Paste an SVG file into the input field, set the animation duration in seconds, and click Render to watch the image draw itself incrementally while the live editor displays the growing SVG code. The tool automatically completes partial SVG markup to ensure valid rendering at each animation step.

Decode QR codes from image files by uploading, dragging and dropping, or pasting them directly into the application. The decoder processes the image data using the jsQR library to extract and display the encoded content, automatically converting URLs into clickable links for convenient access.

Explore how the CSS text-wrap: balance property affects navigation layout and text distribution across multiple lines. This interactive demonstration allows you to toggle the text-wrap balance feature on and off while adjusting the number of visible navigation items to see how the browser distributes text more evenly across lines. Use the slider and checkbox controls to observe the differences in how links wrap and align within the constrained navigation container.

Convert text to NATO phonetic alphabet equivalents for clear communication in radio, military, and aviation contexts. Enter any combination of letters and numbers, then click the convert button to display the phonetic representation with each character separated by spaces. Spaces in the original text are marked as "(SPACE)" in the output.

Record audio through your microphone and send it to OpenAI's GPT-4o audio model along with a text prompt to receive AI-generated responses. The tool converts your recorded audio to WAV format, calculates token usage and associated costs for both text and audio inputs, and displays the API response in both formatted and raw JSON views. Your API key is securely stored locally in your browser, and you can download the recorded audio file for later use.

Extract URLs from copied web page content by pasting HTML into the input area, which automatically identifies and displays all hyperlinks found in the pasted material. The tool filters for valid HTTP links and provides a consolidated list in the output textarea, making it easy to copy all extracted URLs to your clipboard with a single button click.

Query pelican sighting records from Half Moon Bay using SQL commands against an in-browser SQLite database. The tool loads sample data containing observations of various pelican species across local beaches with dates, locations, and counts. Enter any valid SQL query in the textarea and execute it to retrieve and view the results in a formatted table.

Explore an interactive CSS grid layout that demonstrates dynamic element expansion with smooth animations. Click the green cell labeled "1x2" to trigger a symmetric animation that expands the element to fill the entire grid container, then click again to animate it back to its original position. The layout combines CSS Grid positioning with JavaScript event handling to create a polished visual effect that smoothly transitions between states.

Plan events with timezone-aware scheduling and countdown tracking. This application allows you to input event details including title, description, location, date, and time across different US timezones, then automatically calculates the time remaining until the event and generates a shareable Google Calendar link. The tool displays all event information in a formatted summary and provides a convenient way to add the event directly to your Google Calendar account.

Convert raster images to scalable vector graphics using automated tracing technology. Upload a JPG or PNG image by dragging it onto the drop zone or clicking to browse, and the application will generate an SVG representation that can be viewed and copied. The conversion process uses imagetracerjs to intelligently trace image edges and create vector paths suitable for scaling to any size without quality loss.

Explore an interactive map of San Francisco rendered with MapLibre GL and OpenFreeMap tiles, displaying 1000 randomly distributed markers across the city. The demo showcases three different approaches for rendering large numbers of points—scaled markers, custom HTML elements, and GeoJSON circle layers—with the map automatically adjusted to fit all markers in view. Users can interact with the tilted 3D map to navigate and explore the marker distribution across the San Francisco area.

Display your browser's user agent string, which contains information about your web browser, operating system, and device. This identifier is sent with every HTTP request your browser makes and helps websites understand how to optimize their content for your specific platform and browser version.

Render Markdown text with integrated LaTeX mathematical equations in real-time as you type. This tool converts your input into formatted HTML output while simultaneously displaying a live preview with properly rendered math expressions using KaTeX. You can view the generated HTML code and copy it to your clipboard for use in other projects.

Upload files and images to GitHub repositories using the GitHub API. This tool accepts either text content or image files and commits them to a specified repository path with proper authentication via personal access tokens. The interface automatically adapts to show relevant input fields based on whether you're uploading text or an image file.

Calculate the token cost for images used in API requests by uploading or dragging an image file into the tool. The calculator analyzes the image dimensions and divides them into 224-pixel tiles, multiplying the total tile count by 1,000 to determine the token expense. This helps estimate costs when working with vision-based APIs that charge per image token.

View YouTube video thumbnails in multiple resolutions by entering a video URL or ID. This tool extracts and displays all available thumbnail formats from YouTube's image server, allowing you to preview different quality options and copy direct image links. Click on any thumbnail to expand it for a closer look, and use the copy button to save the image URL to your clipboard.

Track productivity sessions with this Pomodoro timer application that manages timed work intervals with customizable durations. Set a goal for each session, choose from preset time intervals ranging from 5 to 60 minutes, and pause or resume as needed while the timer counts down. All session data including start times, end times, and pause history is automatically saved and displayed in a detailed log table, with the ability to export the data as JSON for further analysis or record-keeping.

Read TIFF orientation metadata from JPEG images by uploading or dragging files into the drop zone. The tool parses the EXIF data embedded in the image file to extract the orientation tag, which indicates how the image should be displayed (normal, rotated 90° clockwise, rotated 180°, or rotated 270° clockwise). Debug information shows the file analysis process, including EXIF location, endianness detection, and TIFF header validation.

Visualize real-time audio frequency data from your microphone as an animated spectrum display. This application uses the Web Audio API to capture microphone input, analyze frequencies using FFT (Fast Fourier Transform), and render dynamic bars that respond to sound levels across the frequency spectrum. Grant microphone permissions when prompted to begin the visualization.

Extract and view EXIF metadata from image files, including GPS coordinates and other embedded image data. This tool allows you to upload an image and instantly retrieve detailed information such as geolocation data, camera settings, and timestamps stored within the file. The viewer displays GPS coordinates in decimal format when available and presents all extracted metadata in a structured, readable format.

Generate custom CSS box-shadow effects with interactive controls and real-time preview. Adjust horizontal and vertical offsets, blur radius, spread radius, color, and opacity using intuitive sliders and color picker to visualize shadow changes instantly. Copy the generated CSS code directly to your clipboard for immediate use in your stylesheets.

Compare two PDF documents side-by-side to identify differences between them. Upload or drag and drop two PDF files to view their pages rendered as images, with a third panel highlighting any pixel-level differences in red. This tool is useful for detecting changes between document versions, comparing drafts, or verifying document modifications.

Compare Elo ratings across different language models and dates using this interactive animated bar chart. Load your own JSON data with model names, dates, and Elo scores, then watch the rankings evolve over time with customizable animation speed. The visualization displays the top 20 models at each time point, making it easy to track performance trends and competitive dynamics in the AI landscape.

View CSV data as markers on an interactive map using the ?csv=URL parameter to specify a CSV file containing latitude and longitude columns. The map supports additional customization through query parameters including center to set the initial location, zoom for zoom level, color to change marker color, and marker to add individual points. Map position and zoom level are automatically saved to the URL bar as you navigate, allowing you to share your current view with others.