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Chrono-Debug API Replay

Recreate race conditions instantly. Scrub through a timeline to replay exact historical API responses and watch your UI react as if it's in the past.

Chrono-Debug API Replay

Upload a Network HAR file. A local Service Worker intercepts your localhost fetch requests and replays historical API responses exactly as they occurred based on the timeline below.

Upload HAR Network Log

Export a HAR file from Chrome DevTools Network Tab

Chrono-Debug API Replay

Testing API idempotency and timing issues is notoriously difficult. The Chrono-Debug API Replay acts as a local proxy that intercepts your HTTP requests and allows you to artificially alter their timing, latency, and order.

By simulating network conditions from 'the past' or delaying requests into 'the future', you can uncover race conditions and state-mutation bugs in your frontend applications.

How to use this tool

  1. Configure your frontend to route API calls through the local proxy endpoint provided.
  2. Record a sequence of API calls.
  3. Use the timeline interface to drag requests, altering their latency and arrival order.
  4. Replay the sequence to observe how your application handles the mutated timing.

Examples

Frequently Asked Questions

Do I need to install a desktop app for this?
No, this uses Service Workers to intercept fetch requests directly within your browser session.