Codex

--- title: "Codex" description: "Step-by-step guide for routing Codex through Aurora." icon: "code-xml" --- Aurora is a good fit for Codex because Codex already targets the OpenAI Responses API. Flow: Codex -> Aurora -> upstream model provider ## Before you start - Install Codex on your machine. - Choose an Aurora master key, for example change-me. - Make sure Aurora has the upstream provider key for the models you want to use. <Note> You can keep using Codex with a ChatGPT subscription sign-in, but Aurora still needs a gateway credential from Codex and an upstream provider key of its own. In this guide, OPENAI_API_KEY=change-me is the Aurora master key that Codex sends to Aurora, not your OpenAI Platform key. </Note> ## 1. Run Aurora Start Aurora with a master key and an OpenAI provider key: ``bash docker run --rm -p 8080:8080 \ -e AURORA_MASTER_KEY="change-me" \ -e OPENAI_API_KEY="$OPENAI_API_KEY" \ aurorallm/aurora ` ## 2. Confirm the Responses API with curl Before testing Codex itself, you can optionally verify that Aurora answers a normal Responses API request: This step is optional. If you are sure you have configured a valid OPENAI_API_KEY in Aurora, you can skip it and go straight to step 3. `bash curl -s http://your-aurora-host/v1/responses \ -H "Authorization: Bearer change-me" \ -H "Content-Type: application/json" \ -d '{ "model": "gpt-4.1-mini", "input": "Reply with exactly ok", "max_output_tokens": 16 }' ` If the gateway is wired correctly, the response will contain ok. ## 3. Configure Codex to use Aurora Use a Responses-based provider in your Codex config file: `toml model_provider = "aurora" model = "gpt-4.1-mini" [model_providers.aurora] name = "Aurora" base_url = "http://your-aurora-host/v1" env_key = "OPENAI_API_KEY" wire_api = "responses" ` Then export the Aurora master key for that provider: `bash export OPENAI_API_KEY=change-me ` <Note> Codex 0.122.0 did not use the OPENAI_BASE_URL environment variable in local validation. Use the provider config above, or set openai_base_url in Codex config if you intentionally want to override the built-in OpenAI provider. </Note> ## 4. Run a Codex test prompt `bash codex exec -m gpt-4.1-mini 'Reply with exactly ok and no punctuation.' ` The validated result was: `text ok ` ## DeepSeek V4 Codex sends POST /v1/responses. DeepSeek exposes chat completions instead of a native Responses API, so configure the first-class DeepSeek provider and let Aurora translate the request. `yaml providers: deepseek: type: deepseek base_url: "https://api.deepseek.com" api_key: "${DEEPSEEK_API_KEY}" ` If you previously configured DeepSeek as type: openai, change it to type: deepseek for Codex. The generic OpenAI provider forwards /responses upstream, while the DeepSeek provider translates /responses to /chat/completions. See the DeepSeek guide for the full reasoning effort mapping table (DeepSeek V4 only accepts high and max, so Aurora maps low and medium up to high). Then use the DeepSeek model name in Codex: `toml model_provider = "aurora" model = "deepseek-v4-pro" [model_providers.aurora] name = "Aurora" base_url = "http://your-aurora-host/v1" env_key = "OPENAI_API_KEY" wire_api = "responses" ` ## 5. Check the traffic in Aurora Open the Aurora dashboard audit logs: http://your-aurora-host/admin/dashboard/audit This lets you confirm that Codex is reaching Aurora and inspect the full request and response trail. From the same dashboard, you can keep following your Aurora traffic and usage. ## Current status - the recommended integration path is Codex custom provider -> standard http://your-aurora-host/v1 - Codex custom provider mode sends POST /v1/responses - Codex 0.122.0 sends an uncompressed JSON request body in this path, so the old --disable enable_request_compression workaround is no longer required - ChatGPT subscription sign-in can coexist with the custom provider, but the custom provider still requires the configured env_key ## References - OpenAI Codex discussion: [Deprecating chat/completions support in Codex](https://github.com/openai/codex/discussions/7782) - OpenAI Codex repository: openai/codex ## Validated on April 21, 2026 This guide was validated against: - a local Aurora instance on http://your-aurora-host - Codex CLI 0.122.0 Local validation confirmed: - POST /v1/responses returned 200 OK with curl - codex exec returned ok through Codex -> Aurora -> OpenAI-compatible upstream - Codex sent plain JSON to POST /v1/responses; no Content-Encoding: zstd header was present - a ChatGPT-signed-in Codex session worked with the custom aurora provider when OPENAI_API_KEY was set to the Aurora master key - the same custom provider failed without OPENAI_API_KEY, because the provider env_key` is still required