codex-relay 0.1.1

Responses API ↔ Chat Completions translation bridge for Codex CLI
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codex-relay

A lightweight Rust proxy that translates the OpenAI Responses API (used by Codex CLI) into the Chat Completions API, letting Codex work with any OpenAI-compatible provider — DeepSeek, Kimi, Qwen, Mistral, Groq, xAI, OpenRouter, and more.

Why

Codex CLI speaks the OpenAI Responses API, which is an OpenAI-proprietary stateful protocol. Every other provider exposes the standard Chat Completions API. codex-relay sits between Codex and your chosen provider, translating on the fly — no code changes to Codex required.

Install

# From PyPI — prebuilt binary for your platform
pip install codex-relay

# From crates.io
cargo install codex-relay

Quick start

1. Start the relay

CODEX_RELAY_UPSTREAM=https://api.deepseek.com/v1 \
CODEX_RELAY_API_KEY=$DEEPSEEK_API_KEY \
CODEX_RELAY_PORT=4446 \
codex-relay

2. Configure Codex (~/.codex/config.toml)

model = "deepseek-chat"
model_provider = "deepseek-relay"

[model_providers.deepseek-relay]
name = "DeepSeek"
api_base_url = "http://127.0.0.1:4446/v1"
env_key = "DEEPSEEK_API_KEY"

3. Use Codex normally — it routes through the relay transparently.

Supported providers

Provider Base URL Suggested port
DeepSeek https://api.deepseek.com/v1 4446
Kimi (Moonshot) https://api.moonshot.cn/v1 4447
Qwen https://dashscope.aliyuncs.com/compatible-mode/v1 4448
Mistral https://api.mistral.ai/v1 4449
Groq https://api.groq.com/openai/v1 4450
xAI https://api.x.ai/v1 4451
OpenRouter https://openrouter.ai/api/v1 4452

Any OpenAI-compatible endpoint works.

Features

  • Streaming — full SSE streaming with correct event sequencing
  • Tool calls — accumulates streaming deltas and emits structured function_call items
  • Parallel tool calls — consecutive function_call input items merged into one assistant message
  • Reasoning models — preserves reasoning_content across turns (Kimi k2.6, DeepSeek-R1)
  • Model catalog — proxies /v1/models from the upstream provider

Configuration

Variable Default Description
CODEX_RELAY_PORT 4444 Port to listen on
CODEX_RELAY_UPSTREAM https://openrouter.ai/api/v1 Upstream Chat Completions base URL
CODEX_RELAY_API_KEY (empty) API key forwarded to upstream
RUST_LOG codex_relay=info Log verbosity

Python API

from codex_relay import start

proc = start(port=4446, upstream="https://api.deepseek.com/v1", api_key="sk-...")
# ... use Codex ...
proc.terminate()

Disclaimer

This project is not affiliated with, endorsed by, or sponsored by OpenAI. "Codex" refers to OpenAI Codex CLI, an open-source project licensed under Apache-2.0. codex-relay is an independent, community-built translation proxy.

License

MIT