NetReplay – Capture & Replay Network Requests

Capture every fetch & XHR request on any page. Inspect headers, view response bodies, and replay requests in one click. See every request your page makes. NetReplay is a Chrome extension that captures every fetch and XHR network request on any page, lets you inspect headers and response bodies in a floating panel, and replays any request with a single click — no DevTools, no proxies, no setup. Whether you're debugging a broken API call, validating an endpoint in QA, or tracing what a third-party script is quietly sending, NetReplay gives you a clear, real-time view of every HTTP request your browser makes — directly alongside the page. 🎯 Capture every fetch() and XHR request on any page — automatically, from page load 🔍 Inspect full request headers, response headers, status codes, and response bodies ▶ Replay any captured request instantly and download the response as a JSON file Key Features: --------------------- ✅ Automatic Network Request Capture NetReplay intercepts every fetch() and XMLHttpRequest call the moment a page loads — no button to click first, no configuration required. Every API call, data request, and background poll is recorded. The request list builds in real time as the page runs, giving you a complete picture of all network activity. Unlike Chrome DevTools, you never lose captures by accidentally closing the panel or navigating away. ✅ Full Request & Response Inspection Click any captured request to see everything: HTTP method, full URL, all request headers, request body, response status code, response headers, and the complete response body. JSON responses are automatically pretty-printed for readability. This is the HTTP request inspector chrome developers reach for when they need detail without switching away from the page they're debugging. ✅ One-Click Request Replay Select any captured request and hit Replay. NetReplay resends the exact request — same method, same headers, same body — and shows you the live response immediately. No copy-pasting into Postman, no reconstructing curl commands by hand. Replay is the feature that makes NetReplay different from a plain network logger: you can re-run any request as many times as needed without reloading the page or repeating the user flow that triggered it. ✅ Download Response as JSON Save any captured request and its response to disk as a timestamped .json file. The export includes the request method, URL, headers, body, response status, response headers, and response body — everything in one structured file. Share it with a teammate, diff two responses, or archive it as evidence in a bug report. One click, done. ✅ Copy as cURL Command Generate a ready-to-paste curl command for any captured request in either bash or Windows cmd format. All headers and the request body are correctly quoted and escaped. Paste it directly into your terminal to reproduce the request in isolation, run it in CI, or hand it off for backend debugging — without touching DevTools or writing anything by hand. ✅ URL & Method Filter Type any string into the filter bar to instantly narrow the request list by URL fragment or HTTP method. Debugging a specific endpoint in a page that makes dozens of requests? Filter to it in under a second. The filter is live — it updates as you type without clearing any captured data. ✅ Floating Panel — Stays on the Page NetReplay renders as a floating panel injected into any page via Shadow DOM, so it never interferes with the page's own layout or styles. Open it by clicking the toolbar icon or the floating button on the page. Close it when you're done. It stays visible as you interact with the page — you don't have to toggle back and forth between a DevTools tab and the live page to see what's happening. ✅ Enable / Disable Toggle The popup's toggle switch lets you pause capturing and hide the panel across all tabs without uninstalling the extension. Useful when you're done debugging and don't want the panel visible on every page. Re-enable it instantly when you need it again. The toolbar badge shows ON/OFF state at a glance. ✅ Minimal Permissions NetReplay requests only two permissions: storage (to remember the on/off toggle state) and the content script host match for all URLs (required to inject the capture script on any page you visit). No remote connections. No data leaves your browser. Works On: --------------------- NetReplay is an API request capture chrome extension that works on every website that makes network requests — which is essentially every modern website: ▶ Web applications — React, Vue, Angular, or any SPA that communicates with a backend API. Capture the exact payload your app sends and the exact response it receives. ▶ REST APIs — Watch every GET, POST, PUT, PATCH, and DELETE call your page makes. Filter by method to isolate write operations. ▶ GraphQL endpoints — Capture the full query body and the complete response payload. Useful when introspection isn't available or the schema is unclear. ▶ Third-party API integrations — See exactly what requests your page makes to analytics, payment, authentication, or data providers. ▶ E-commerce sites — Inspect add-to-cart, checkout, and inventory API calls during QA testing. ▶ Authentication flows — Observe login, token refresh, and session API calls without a proxy. ▶ Streaming and media sites — Capture manifest requests, segment fetch calls, and DRM license requests for debugging playback issues. ▶ Internal tools & dashboards — Debug API calls in tools that don't have good error surfaces, without setting up a proxy or modifying source code. ▶ Any page with fetch() or XMLHttpRequest — If the page makes HTTP requests through JavaScript, NetReplay captures them. Note: NetReplay captures JavaScript-initiated requests (fetch and XHR). Navigation requests and requests made directly by the browser (resource loads like images, scripts, stylesheets initiated by HTML parsing) are not captured — only programmatic API calls. Use Cases: --------------------- NetReplay solves specific problems that come up daily in web development, QA, and API work: 🐛 Debugging a Broken API Call Your frontend shows an error but the error message is generic. Open NetReplay, reproduce the action, and find the failing request in the list immediately. See the exact status code, response headers, and error body the server returned — without hunting through the DevTools network tab or adding console.log statements to the source code. 🔁 Reproducing an Intermittent Bug A request fails once every ten tries and you can't figure out why. With NetReplay, you can replay the captured request repeatedly to isolate whether the issue is in the request itself or in server-side state. You don't need to re-run the full user flow each time — just hit Replay. 🧪 QA Endpoint Validation You need to confirm that a user action sends the right payload to the right endpoint with the right headers. Open NetReplay, perform the action, and inspect the captured request. No proxy configuration, no Charles, no Fiddler — just the extension and the page. 🕵️ Investigating Third-Party Scripts A third-party analytics, chat, or advertising script is making unexpected requests. NetReplay shows you exactly which URLs it's hitting, what it's sending, and what it's receiving — with no code changes and no proxy setup. 📋 Generating cURL Commands for Backend Teams A backend engineer needs to reproduce a frontend request to debug a server-side issue. Use NetReplay to capture the request as it actually happens in the browser — cookies, auth headers, and all — and send them a copy-paste-ready curl command in seconds. 📁 Archiving API Response Snapshots Download any request and response as a structured JSON file for documentation, bug reports, or response diffing between environments. Useful when you want a record of exactly what an API returned at a specific point in time. 🔐 Security Testing & Review Review what data your page sends to external services — authentication tokens, user identifiers, analytics payloads. NetReplay makes it easy to audit outbound requests without setting up a full proxy or man-in-the-middle tool. ⚡ Faster Than Opening DevTools The DevTools network tab requires: opening DevTools, switching to the Network tab, often reloading the page to catch early requests, and then navigating away from the DevTools panel to interact with the page. NetReplay is always there — floating on the page, capturing from the start, without any of those steps. How NetReplay Compares: --------------------- The Chrome DevTools Network tab is powerful — but it requires a workflow that breaks your focus. NetReplay is designed around the problems that make DevTools slow for everyday API debugging: — DevTools requires opening a separate pane and switching focus away from the page. NetReplay is a floating panel on the page itself. — DevTools loses network history when you close it or navigate. NetReplay maintains captures as you work. — DevTools has no one-click replay. NetReplay replays any request with a single button. — DevTools requires manual reconstruction of curl commands. NetReplay generates them instantly. — Postman Interceptor requires Postman installed and sends data through Postman's cloud. NetReplay is fully local and standalone. — Requestly is a rule-based request modification tool — a different job entirely. NetReplay is a passive capture and replay tool with no modification rules to configure. — ModHeader modifies outgoing headers but doesn't capture or replay requests. NetReplay's position: zero-setup, local-only, always-on capture with instant replay — the fastest path from "something went wrong" to "I can see exactly what happened." All request capture and replay happens entirely inside your browser. NetReplay never transmits captured request data, response data, URLs, headers, or any other information anywhere. No external service is contacted at any point. The only data stored is your on/off toggle preference, saved locally via chrome.storage.local. You can clear it at any time from Chrome's extension settings. Nothing is synced to any server. Permissions Explained: --------------------- NetReplay requests only the permissions it actually needs: • storage — Required to save your enable/disable toggle state across browser sessions so the extension remembers whether you had capture turned on. • (content script match) — Required to inject the capture script on any website you visit. Without this, NetReplay could only capture requests on a fixed list of hardcoded domains. The capture script runs locally in your browser — it does not send data anywhere. No other permissions are requested. No tabs permission. No webRequest permission. No activeTab permission. The extension cannot modify requests, redirect traffic, or read your browsing history — it only observes JavaScript-initiated fetch and XHR calls on the active page. Frequently Asked Questions: --------------------- Q: Does it capture requests that happen before I open the panel? A: Yes. The capture script is injected at document_start — before the page's own JavaScript runs. Every fetch() and XHR call is captured from the very first one, whether or not the panel is open. Q: Does it work on single-page apps (React, Vue, Angular)? A: Yes, fully. SPAs communicate almost entirely through fetch() and XHR. NetReplay captures every API call your SPA makes, including those triggered by navigation within the app. Q: Will it capture WebSocket messages? A: Version 1.0 captures fetch() and XMLHttpRequest only. WebSocket message capture is planned for a future release. Q: Does replaying a request log me out or change server-side state? A: Replayed requests are sent with credentials: 'include', meaning your current session cookies are attached — the same as the original request. If the original request modified state (a POST, PUT, DELETE), replaying it will also modify state. Use Replay on idempotent requests (GET) or on POST requests where you understand the side effects. Q: Why don't I see any requests in the list? A: Make sure the enable toggle in the popup is ON. If the toggle was OFF when the page loaded, the capture script was hidden and requests may not have been collected. Toggle it ON and reload the page. Q: Does it work with HTTPS requests? A: Yes. NetReplay intercepts fetch() and XHR at the JavaScript level, before the browser's TLS layer. Protocol (HTTP or HTTPS) has no effect on what NetReplay can capture. Q: Can I use it to test APIs I'm building locally? A: Yes. NetReplay works on localhost and any URL — there are no domain restrictions. Q: Does it capture requests from iframes? A: The capture script is injected into the top-level page. Requests made by cross-origin iframes are not captured, as the content script cannot access cross-origin iframe contexts. Q: Is captured data stored between page reloads? A: No. Captured request data lives in memory only. Reloading the page clears the list and starts a fresh capture. This is intentional — it keeps the panel fast and avoids accumulating stale data. Q: Does it work on all operating systems? A: Yes. NetReplay runs on Chrome for macOS, Windows, and Linux — any desktop platform where Chrome is supported. Latest Changes: --------------------- Version 1.0 — April 2026 - Initial release - Automatic capture of fetch() and XMLHttpRequest from document_start - Full request inspection: method, URL, request headers, request body - Full response inspection: status code, response headers, response body (auto pretty-prints JSON) - One-click Replay with live response display - Download request + response as a timestamped .json file - Copy as cURL command (bash and Windows cmd formats) - URL and method filter bar - Floating Shadow DOM panel — works on any page without style conflicts - Enable/disable toggle in popup with toolbar badge (ON/OFF) - NetReplay icon set at 16×16, 48×48, and 128×128 resolutions - Permissions: storage only (activeTab not required)