jsknown

jsknown is an open source JavaScript asset recovery tool for security research, source map reversal, and AI-agent-ready code review workflows.

It runs a local ingestion server, receives browser/proxy traffic from the included Burp Suite extension, mirrors JavaScript and HTML assets to disk, beautifies minified code, discovers lazy-loaded chunks, fetches source maps, and reconstructs original source trees when source maps contain sourcesContent.

Features

• URL-mirrored directory structure for captured HTML and JavaScript.
• Automatic JS and HTML beautification without overwriting originals.
• Webpack, Vite, and Next.js chunk discovery.
• Recursive lazy-loaded chunk fetching with configurable rate limiting.
• Automatic source map discovery from comments, headers, inline data URLs, and sibling .map URLs.
• Source map reversal into original source layout with safe path sanitization.
• JXScout-inspired AST findings for security-oriented JavaScript review.
• Agent-ready JSONL metadata for assets, relationships, and findings.
• Burp Suite extension that streams matching responses into the local server.
• GitHub Actions for tests, multi-platform binaries, plugin JAR builds, and releases.

Quick Start

cargo install --path crates/jsknown-cli
jsknown serve --project default

Then load the Burp Suite plugin JAR and keep the default server URL:

http://127.0.0.1:3333

Captured projects are written to:

~/jsknown/<project>

See INSTALL.md for full installation and Burp setup instructions.

Project Layout

original/                 Raw captured HTML and JavaScript
beautified/               Formatted versions for review
sourcemaps/raw/           Downloaded or extracted source maps
sourcemaps/reversed/      Recovered original sources
analysis/                 Per-file AST analysis JSON
metadata/assets.jsonl     Asset index for tools and AI agents
metadata/relationships.jsonl
metadata/findings.jsonl

CLI

jsknown serve \
  --host 127.0.0.1 \
  --port 3333 \
  --project default \
  --rate-per-second 2 \
  --fetch-concurrency 5

Useful flags:

• --scope <pattern> filters captured URLs. Can be repeated.
• --output <path> changes the output root.
• --rate-per-second <n> controls chunk and source map fetches.
• --rate-per-minute <n> applies a minute-level cap.
• --fetch-concurrency <n> controls concurrent follow-up downloads.
• --max-body-bytes <n> rejects oversized captured responses.

Security Notes

jsknown stores application code and metadata locally. Only run it for systems you are authorized to test. The chunk discovery engine does not execute arbitrary JavaScript; it uses static parsing and constrained string evaluation for known bundler runtime shapes.

License

MIT. See LICENSE.