Debug HTTP API calls
between apps and backends

Proxy-less capture

Debug traffic from apps that do not use your browser proxy

HTTP Debugger captures traffic at the system level, so apps connect directly to the destination server — no proxy in the path. That makes it useful for Windows desktop apps, services, Java/.NET clients, Android emulators, and local web servers.

• No browser proxy changes
• 32-bit and 64-bit process traffic
• Client and local server traffic

Modern protocols

Understand streaming APIs, not just request/response calls

Modern apps and AI agents often stream data instead of returning one simple JSON response. HTTP Debugger exposes HTTP/2 streams, WebSocket frames, Server-Sent Events, and gRPC messages in a dedicated Messages / Events pane.

• HTTP/2 stream details
• WebSocket frames
• Server-Sent Events and gRPC messages

Request replay

Reproduce API issues without changing the client code

Drag a captured request into Submitter, adjust headers, cookies, body, method, or URL, then resend it to verify auth, CORS, routing, validation, and backend behavior.

• Edit and resubmit sessions
• HTTP/2 Submitter support
• Compare working and failing calls

Server simulation

Mock server responses and modify HTTP traffic without changing server code

Use Auto-Reply, HTTP Modifier, and TCP/IP Redirector to simulate server errors, swap in staging endpoints, rewrite response headers, drop or change cookies, and force redirects — without touching the backend.

• Auto-Reply mocked responses
• Modify response headers and body
• Redirect to a different server

Analysis

Pinpoint slow, broken, or important requests

Use timings, highlighting rules, filters, charts, bookmarks, and exports to narrow large captures into the requests that explain a bug or performance issue.

• Timings and charts
• Quick filters and highlighting
• Excel, JSON, XML, CSV/TSV export