render-fetch
Drop-in upgrade to Claude Code's WebFetch — handles JS-rendered pages automatically.
Claude's built-in WebFetch doesn't execute JavaScript. Modern SPAs return empty skeletons. render-fetch auto-detects whether a page needs a real browser and routes accordingly — no config needed.
Installation
Add to your Claude Code settings (~/.claude/settings.json):
{
"mcpServers": {
"render-fetch": {
"command": "npx",
"args": ["-y", "render-fetch"]
}
}
}
First run installs Chromium (~150MB, one-time). Subsequent runs are instant.
How it works
URL in
│
├─ GET page (fast, reuses response)
│
├─ Score for JS-rendering signals
│ <div id="root/app/__next"> +3
│ thin body (<500 chars) +2
│ data-reactroot / ng-version +2
│ window.__REDUX_STATE__ +2
│ bundled JS patterns +1
│ .md / docs domain -3
│
├─ Score < 3 → Static path
│ HTTP → cheerio → Readability → markdown
│
└─ Score ≥ 3 → Browser path
Playwright headless → networkidle → Readability → markdown
Tools
| Tool | What it does | Key params | Returns |
|---|---|---|---|
fetch | Fetch page as markdown (auto-detects mode) | url, mode (auto/static/browser), maxLength (default 50k), timeout (default 30s) | Clean markdown |
fetch_raw | Fetch page as raw HTML | url, mode, timeout | Raw HTML string |
screenshot | Take a viewport screenshot | url, fullPage (default false), timeout | Base64 PNG (max 2MB) |
Why not always use the browser? Static path averages ~200ms. Browser path averages 2–3s plus Chromium launch overhead on first request.
Known limitations
- DNS rebinding: hostname validation happens before the request; a malicious server could theoretically redirect to a private IP after validation. Mitigation planned for v1.1.
- Local use only: not designed for multi-tenant server deployments. For that, put a rate-limiting reverse proxy in front.
- Chromium install: ~150MB one-time download on first browser-mode request.
Contributing
See CONTRIBUTING.md.
License
MIT © 2026 sub-techie09