Shaper

A Firefox extension that captures API traffic as you browse, infers schemas from what it sees, and exports structured documentation. Supports HTTP, GraphQL, gRPC-Web/Protobuf, and SSE.

Install

npm install
npm run build

Load dist/ as a temporary add-on in about:debugging.

Usage

1. Click the Shaper icon, hit All Tabs or + This Tab
2. Browse — the badge pulses green and counts endpoints as they're captured
3. Click Open Dashboard to see everything Shaper has learned
4. Export as OpenAPI, HAR, .proto, or JSON from the dashboard

Alt+Shift+C toggles capture on the active tab.

What it does

• Groups raw requests into endpoint patterns automatically
• Infers request/response JSON schemas, refined with every new sample
• Decodes protobuf wire format without a schema, infers .proto definitions
• Tracks query parameter values and marks which are optional vs required
• Generates curl commands, copyable headers, and structured exports

Development

npm run watch   # rebuild on changes
npm test        # 91 vitest tests

Firefox Manifest V2 — required for filterResponseData, which has no MV3 equivalent.

License

GPL-3.0