Dev Proxy

An intelligent MITM proxy tool implemented in Go, designed for AI developers to intercept, modify, and adapt complex LLM API requests (supporting OpenAI Responses API transformation).

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✨ Core Features

• 🔒 HTTPS MITM Support - Automatically intercept and decrypt HTTPS traffic.
• 🤖 AI Protocol Adaptation - Exclusive support for automatically converting OpenAI's latest Responses API (/v1/responses) to the standard Chat Completions API.
• 🛠️ Tool Call Transformation - Automatically wrap Responses API built-in tools (e.g., web_search) into standard function_call format, ensuring compatibility with all upstream providers (e.g., DeepSeek, SiliconFlow).
• 🌊 Streaming Protocol Enhancement - Automatically complete complex streaming event sequences (created -> added -> delta -> done -> completed), ensuring perfect compatibility with Codex and OpenAI SDKs.
• 🎯 URL Matching - Supports both regex and string matching.
• ✏️ Header Overwriting - Flexible modification of headers like User-Agent, Authorization, etc.
• 🔄 Upstream Proxy - Supports forwarding to HTTP/SOCKS proxies (e.g., Clash).
• 🎲 Random Port - Automatically assigns available ports to avoid conflicts.
• 🔐 Process Isolation - Only proxies the started subprocess, not affecting the rest of the system.
• 💻 Interactive App Support - Supports interactive programs like vim, bash, python, etc.
• 📝 Detailed Logging - Provides detailed traffic logs and plugin execution records for debugging.

🚀 Quick Start

Installation

Install with Go:

go install github.com/daydaychen/devproxy@latest

Build from source:

git clone https://github.com/daydaychen/devproxy.git
cd devproxy
make build
./devproxy --help

Basic Usage

devproxy [flags] -- <command> [args...]

📖 Plugins & AI Adaptation Examples

1. OpenAI Responses API Adaptation (responses-api plugin)

If you are using tools that support the new Responses API (like Codex) but want to connect to an upstream that only supports standard Chat Completions (like DeepSeek), use this plugin:

rules:
  - name: "adapter-to-deepseek"
    match: ["https://api.openai.com/v1/responses"]
    plugins:
      - "responses-api" # Automatically handles bi-directional conversion
    overwrite:
      Authorization: "Bearer your-deepseek-key"

Features:

• Converts input_text to text.
• Wraps built-in tool web_search into function calls.
• Fixes additionalProperties validation issues for various providers.
• Completes all required events in the streaming response to prevent client disconnects.

2. Codex Content Format Fix (codex-fix plugin)

For models (like Minimax, DeepSeek) that return non-standard JSON arrays in content when using CoT or tool calls, this plugin flattens them to strings for Codex compatibility:

rules:
  - name: "fix-codex-content"
    match: ["/chat/completions"]
    plugins:
      - "codex-fix" # Flattens content: [{type: "text", text: "..."}] to string

3. Regular Header Overwriting

rules:
  - name: "github-api"
    match: ["github.com"]
    overwrite:
      Authorization: "token your-token"
      User-Agent: "GithubBot"

⚙️ CLI Flags

Flag	Short	Description	Example
--config	-c	Config file path (YAML)	--config config.yaml
--match	-	URL matching rule (can be multiple)	--match "domain.com/api"
--overwrite	-	Header overwrite (format: header=value)	--overwrite ua=Bot
--upstream	-	Upstream proxy address	--upstream http://127.0.0.1:7890
--port	-	Specify proxy port (default random)	--port 8888
--verbose	-V	Detailed log output	--verbose
--version	-v	Show version	devproxy -v

🛡️ Security

⚠️ Warning: This tool sets environment variables like NODE_TLS_REJECT_UNAUTHORIZED=0 to bypass HTTPS certificate verification. Only use in development and testing environments. Do not use in production.

📄 License

MIT License - see the LICENSE file for details.