Simon Willison's Weblog: Tools

.blend URL Viewer

2026-09-09T23:58:32+00:00

View Blender .blend files directly in your browser by pasting a URL to a CORS-accessible file or GitHub repository link. The viewer renders mesh geometry with materials, lighting, and optional saved camera positions from Blender 5.x files, and provides interactive orbit controls, wireframe mode, and model fitting capabilities.

Video compressor

2026-09-07T18:29:07+00:00

Video compressor

Compress videos in your browser using FFmpeg compiled to WebAssembly. Upload a video file to generate multiple encoded versions with different quality settings and output sizes, then compare and download the smallest file that meets your needs. All processing happens locally with no uploads to external servers.

Mercator ↔ Equal Earth

2026-09-07T16:24:16+00:00

Mercator ↔ Equal Earth

View an interactive animated map that morphs between Mercator and Equal Earth projections using a slider or play button. The visualization demonstrates how different map projections represent the world, with controls to blend between the two projection types and observe how they preserve different geographic properties.

GeoJSON Map Viewer

2026-09-01T18:05:45+00:00

GeoJSON Map Viewer

View and visualize GeoJSON data on an interactive OpenStreetMap with customizable styling options. Paste GeoJSON objects (Feature, FeatureCollection, or Geometry) into the editor, adjust fill color and opacity, and render the features directly on the map. Add multiple shapes with individual styling—each shape is numbered and can be removed, later shapes draw on top of earlier ones, and style changes apply live to the rendered map.

CORS Chat

2026-08-15T14:49:54+00:00

CORS Chat

Chat directly with any OpenAI Responses-compatible API endpoint using browser-accessible CORS headers. Configure custom endpoints with optional bearer token authentication and additional HTTP headers, create multiple conversations with different models and request settings, and persist everything locally in your browser.

Slack Emoji Maker

2026-07-31T20:18:05+00:00

Slack Emoji Maker

Create custom Slack emoji from any image by automatically removing backgrounds, cropping to square, and resizing to meet Slack's requirements (under 128KB PNG). The tool provides visual editing controls including color-based background removal, square cropping with handles, transparency trimming, and color reduction, along with real-time preview in light and dark Slack themes.

SQLite Query Explainer

2026-07-18T17:19:10+00:00

SQLite Query Explainer

View Mozilla Bugzilla bug reports and run SQL queries against a SQLite database to see exactly how SQLite executes them. The tool annotates every line of `EXPLAIN QUERY PLAN` and low-level `EXPLAIN` bytecode output with plain-English descriptions of what the query planner and virtual machine are doing.

LLM cliché highlighter

2026-07-17T12:11:11+00:00

LLM cliché highlighter

View Mozilla Bugzilla bug reports and identify text containing clichéd phrases commonly found in language model outputs. Paste text into the analyzer or load it from a URL via the Jina Reader proxy to detect patterns including "no X, no Y" chains, "sit with that," "you already know," and phrases from Wikipedia's Signs of AI writing guide.

Mermaid to ASCII art (mermaid-ascii)

2026-07-16T14:57:39+00:00

Mermaid to ASCII art (mermaid-ascii)

Convert Mermaid diagram syntax into ASCII and Unicode box-drawing art rendered entirely in your browser using a Go library compiled to WebAssembly. The tool supports flowcharts with labeled edges, subgraphs, and color definitions, as well as sequence diagrams with notes and control flow fragments, while offering customizable padding and output options.

Mermaid to Unicode box art (grok-mermaid)

2026-07-16T00:33:18+00:00

Mermaid to Unicode box art (grok-mermaid)

Convert Mermaid diagram syntax into terminal-style Unicode box-drawing art rendered entirely in your browser using WebAssembly. The tool supports flowcharts, sequence, state, class, and ER diagrams, with other diagram types falling back to a framed source listing. You can adjust the output width, copy the rendered diagram as text, or generate a shareable link to your diagram.

github-code Web Component

2026-07-07T16:18:16+00:00

github-code Web Component

Embed code snippets from GitHub files directly into web pages using the github-code web component. Enter a GitHub URL with a line fragment (e.g., `#L33-L54`) to preview and generate embed code that displays the specified lines without syntax highlighting. Bookmarked URLs are preserved in the page fragment for easy sharing.

HTML table extractor

2026-06-29T23:38:21+00:00

HTML table extractor

Extract tables from pasted content and convert them to multiple formats. Paste HTML, rich text, or plain text containing tables, and the tool automatically detects and displays each table with a preview, then allows you to export it as HTML, Markdown, CSV, TSV, or JSON. You can also import tables directly from Wikipedia by searching for page titles.

OPFS + Pyodide test harness

2026-06-23T18:58:54+00:00

OPFS + Pyodide test harness

Test and manage the Origin Private File System (OPFS) across desktop and mobile browsers with an interactive interface powered by Pyodide. Create, read, and delete files in OPFS, run SQL queries against SQLite databases stored in the file system, and verify persistence across page reloads through a comprehensive activity log and capability detection panel.

— a still that plays

2026-06-17T03:56:10+00:00

— a still that plays

Datasette extras explorer

2026-06-11T15:10:07+00:00

Datasette extras explorer

Query Datasette JSON endpoints and discover available extras by entering a URL and selecting which extras to request. The interface displays the returned JSON response with syntax highlighting and allows you to examine which extras are supported by your Datasette instance, with support for sharing configurations via URL hash parameters.