Next API Capture

Inspect server (SSR/RSC) + client API calls of Next.js App Router apps in a DevTools panel.

In the Next.js App Router, most data is fetched on the server — during the RSC render, inside route handlers, and inside server actions. Those requests never show up in the browser's Network tab, which makes them hard to see while you build and debug. Next API Capture instruments fetch (and Node http/https — so axios, got and node-fetch are covered too) on the server, correlates every call to the page navigation that triggered it, and streams them to a dedicated DevTools panel — right next to your client-side fetch and XHR calls. What you get: • Server + client capture — server:rsc, server:route-handler, server:action, plus client fetch and XHR. • A real DevTools panel — filter by source, search by URL, group by navigation, clear-on-nav, live counts. • Full request / response detail — headers and bodies (gzip/deflate/br decoded), with a resizable detail pane. • Safe by default — never auto-on in production; sensitive headers masked; bodies size-capped and pattern-redacted. • Drop-in and fail-safe — three small touch-points; feature-detects at runtime and degrades gracefully (warns, never throws). How it works (in your app): instrumentation.ts → registerCapture() middleware.ts → createCaptureMiddleware() Load this extension and open the “API Capture” panel in DevTools. The library streams captures to the extension over a loopback dev WebSocket (127.0.0.1). The extension only runs on http://localhost and http://127.0.0.1, and nothing is sent to any remote server. Open source: https://github.com/yeo11200/next-api-capture