APXY vs mitmproxy: When You Need More Than Interception

mitmproxy is excellent. If you need a scriptable, open-source HTTPS proxy with Python-based addons, deep protocol support, and a decade of battle-testing, it is the right choice. This is not a hit piece.

But developers who search for mitmproxy often have a broader problem than mitmproxy was designed to solve. They want to intercept traffic and mock responses, run without writing Python, and get a UI when they need one. For that combination, you need a different tool.

What mitmproxy does well

mitmproxy is the gold standard for raw HTTPS interception with programmatic control. Its strengths:

• Python scripting with full addon API — deeply customize how traffic is handled, transformed, or blocked
• Multiple interface modes — mitmproxy (interactive TUI), mitmdump (CLI stream), mitmweb (browser UI)
• Protocol breadth — HTTP/1, HTTP/2, HTTP/3, WebSocket, DNS-over-HTTPS, Wireguard proxy mode
• Open source and free — no license required
• Active community — extensive documentation, plugins, and third-party tutorials

If you are building a security research tool, writing custom protocol parsers, or need fine-grained Python control over every byte of traffic, mitmproxy is the right foundation.

Where mitmproxy stops

mitmproxy is a proxy. It captures and transforms traffic. It does not:

• Serve mock responses from a rule engine — you can write a Python addon that returns fake data, but there is no built-in concept of "if URL matches X, return this JSON"
• Provide a mock rule UI — every mock must be coded, not configured
• Record and replay traffic as test fixtures — no built-in record-and-replay workflow
• Have a Web UI for viewing and filtering historical traffic — mitmweb shows a live stream, not a searchable history
• Export traffic as HAR — requires a custom addon or third-party tools
• Integrate with AI coding agent workflows — no built-in token optimization, no agent-oriented output formats

The moment a developer needs to mock a REST endpoint for frontend development, simulate an error state for testing, or give an AI agent a compact view of recent traffic, they hit mitmproxy's edges.

The core difference

mitmproxy is built around the question: what did this request look like?

APXY is built around: what should I do with this request?

mitmproxy answers the first question excellently. APXY answers both — interception plus a rule engine that lets you decide whether to forward, mock, redirect, modify, or script each matched request.

| Capability | mitmproxy | APXY | |---|---|---| | HTTPS interception | Yes | Yes | | CLI-first workflow | Yes | Yes | | Python addon scripting | Yes | — | | JavaScript scripting | — | Yes | | Built-in mock rule engine | — | Yes | | Mock rules via CLI (no code) | — | Yes | | Record and replay | — | Yes | | HAR import / export | Via addon | Built-in | | Web UI with traffic history | Limited | Full | | OpenAPI schema validation | — | Yes | | Token-optimized output for AI agents | — | Yes | | macOS certificate auto-trust | Manual | Automatic |

When to use mitmproxy

• You are doing security research or protocol analysis
• Your workflow requires Python scripting at every layer
• You need HTTP/3, WebSocket, or DNS-over-HTTPS support
• You are comfortable writing addons and do not need a UI
• You want a pure, dependency-light proxy with no extras

When to use APXY

• You need both interception and mocking without writing code
• You want mock rules you can add with a single CLI command
• You are doing frontend development against a backend that is not ready
• You want to give an AI coding agent access to recent traffic
• You need a record-and-replay workflow for regression testing
• You want a searchable traffic history, not just a live stream
• You are setting up a team project where rules are version-controlled in .apxy/

They can coexist

mitmproxy and APXY are not fighting for the same job. A team might use mitmproxy for security audits and protocol research while using APXY for day-to-day API development, mocking, and agent-assisted debugging.

If you are currently using mitmproxy and find yourself writing Python addons to return fake JSON, building a record-replay workflow from scratch, or piping output through jq to get readable traffic summaries — those are the gaps APXY fills directly.

Install APXY free and run it alongside your existing workflow.