Preview PDF HTTP responses directly in the Caido Response viewer, rendered with pdf.js.

When an HTTP response is a PDF, this plugin adds a PDF Preview tab to the response pane and renders it inline — with selectable text, a thumbnail sidebar, zoom, page navigation and download. The tab appears everywhere Caido shows a response: HTTP History, Replay, Intercept and Sitemap.

• 📄 Automatic detection — the tab only shows up for PDFs (via Content-Type: application/pdf or the %PDF- magic bytes).
• 🔤 Selectable text — real pdf.js text layer, so you can select and copy.
• 🖼️ Thumbnail sidebar — click a page to jump to it; the active page is highlighted and kept in sync while you scroll.
• ⚡ Lazy rendering — pages and thumbnails render on demand, so large PDFs stay responsive.
• 🔍 Zoom & navigation — zoom in/out, previous/next page, page counter.
• 💾 Download — save the PDF from the response.
• 🧱 Byte-faithful — a small backend plugin reads the real response bytes and transparently handles gzip/deflate encoded bodies.

Screenshots coming soon.

Once published, open Caido → Plugins → Community Store, search for “PDF Preview”, and install it.

1. Download plugin_package.zip from the latest release.
2. In Caido, go to Plugins → Installed → Install Package and select the zip.

• Frontend (packages/frontend) — a Vue 3 component registered via sdk.<page>.addResponseViewMode(...). Its when() predicate inspects the raw response so the tab only shows for PDFs. Rendering uses pdf.js with the worker inlined into the bundle (?worker&inline), so there is no separate asset for Caido to serve.
• Backend (packages/backend) — exposes getResponseBodyBase64(id). The frontend can only see response.raw as a JS string, which is unreliable for binary data. The backend reads the real bytes through sdk.requests.get(id).response.getBody().toRaw() and base64-encodes them so the PDF survives the JSON-RPC boundary intact, reporting Content-Encoding so the frontend can decompress. If the backend call fails, the frontend falls back to reconstructing bytes from response.raw.

Requires pnpm and Node 18+.

pnpm install
pnpm build      # -> dist/plugin_package.zip
pnpm watch      # iterative development
pnpm -r typecheck

caido.config.ts            # plugin config -> generates manifest.json + zip
packages/
  backend/src/index.ts     # getResponseBodyBase64 RPC endpoint
  frontend/
    src/index.ts           # registers the PDF Preview response view mode
    src/pdf.ts             # pdf.js worker setup + page/text-layer rendering
    src/bytes.ts           # %PDF detection + gzip/deflate normalization
    src/views/PdfPreview.vue
    src/types.ts           # typed backend API surface

See PUBLISHING.md for the full release + Caido store submission process (signing key, GitHub release, store PR).

This plugin bundles pdf.js (pdfjs-dist), © Mozilla, licensed under the Apache License 2.0. See NOTICE.

MIT © William Le Berre