codex-relay 0.1.3

Responses API ↔ Chat Completions translation bridge for Codex CLI

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