DevKit – API Debugger & Network Inspector

Capture, inspect, replay, mock, and compare web API traffic locally.

DevKit – API Debugger & Network Inspector is a local-first workspace for understanding and debugging HTTP and web API behavior without opening Chrome DevTools or constantly switching to a terminal and separate API clients. Use DevKit to: - Explicitly record completed requests from the active browser tab without opening Chrome DevTools. - Search and filter by method, status, resource type, or URL. - Inspect request and response headers, query parameters, bodies, and available timing data. - View JSON as pretty text, raw text, or a navigable tree with copyable JSON paths. - Inspect GraphQL, gRPC-Web binary/text frames, Proto messages, WebSocket frames, and Server-Sent Events. - Modify and replay supported HTTP requests with an explicit safety confirmation for POST, PUT, PATCH, and DELETE. - Compare original and replay versions side by side across query parameters, headers, request bodies, and response bodies. - Mock, block, delay, or override matching requests and responses while Full Capture is active. - Save requests in collections with environments, assertions, regression baselines, scenarios, and data-driven replay. - Copy a request as cURL, JavaScript fetch, or Go net/http boilerplate. Privacy is built into the workflow. Recording is off by default, DevKit attaches only to tabs where Record is pressed, tab sessions remain independent in the browser, sensitive headers are masked, and DevKit has no analytics, telemetry, account, cloud sync, or developer-operated backend. Chrome displays a debugging indicator while recording is active. Chrome may not expose every network field, and replay cannot reproduce certain browser-controlled headers. DevKit clearly marks unavailable data instead of inventing it.