tools

tools.simonwillison.net

Miscellaneous HTML+JavaScript tools I have built, almost all with the assistance of LLMs.

Prompts used are linked to from the commit messages for each tool.

OCR for PDF files and images that runs entirely in your browser
Render Markdown renders Markdown to HTML using the GitHub Markdown API
Annotated presentation creator to help turn slides into an annotated presentation
Box shadow CSS generator generates the CSS for a box shadow with interactive settings
Compare PDFs provides a visual comparison of the pages of two PDF files
Image resize and quality comparison converts an image to JPEGs using a number of different quality settings so you can select the smallest file size that is still usefully legible (how I built this)
YouTube Thumbnails - paste in the URL to a YouTube video, get back all of the URLs to thumbnail images of different sizes for that video
SVG to JPEG/PNG - turn an SVG file into a rendered JPEG or PNG (how I built this)
Jina Reader - convert any URL to copyable Markdown using the Jina Reader API
Extract URLs - copy a section from a web page to your clipboard, paste it in here and get back a plain text list of all of the linked URLs from that section
EXIF Data Viewer - view EXIF data for an image
MDN Browser Support Timelines - search for web features and view the browser support timeline pulled from MDN
Timestamp Converter - convert between Unix timestamps and human-readable dates
Timezones - select two timezones to see a table comparing their times for the next 48 hours
Social media cropper - open or paste in an image, crop it to 2x1 and download a compressed JPEG for use as a social media card

Haiku generates Haikus from your camera using Claude 3 Haiku
Chrome Prompt Playground is a UI for running prompts through the Google Chrome Canary experimental Gemini Nano LLM and saving the results in local storage
Gemini API Image Bounding Box Visualizer - run prompts against Google Gemini models that return bounding box co-ordinates and visualize them against the original image, see this post for details
Claude Token Counter - counts the number of tokens in a Claude prompt
OpenAI audio input - record audio through the microphone and send it to OpenAI’s audio model
OpenAI audio output - run prompts against OpenAI that produce audio output and listen to it or download it from the browser

Arena animated animates the progression of the LMSYS Chatbot Arena, inspired by this visualization by Peter Gostev (via Time-Winter-4319 on Reddit)
California Clock Change - shows when the clocks will next change for daylight saving time in California
Bluesky WebSocket Firehose showing a live firehose of Bluesky activity, described here
Prompts.js small JavaScript library enabling await Prompts.alert("hi") and await Prompts.confirm("Continue?") and await Prompts.prompt("Enter your name")

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