Passing the RelayRouter base URL and key as environment variables in Docker Compose

To pass RelayRouter settings in Docker Compose, store your API key and base URL in a .env file next to docker-compose.yml, then reference them under the service's environment key with ${VAR} interpolation. Use https://relayrouter.io/v1 for OpenAI compatible SDKs or https://relayrouter.io for Anthropic compatible SDKs. Keep the .env file out of version control. Your application code reads the variables and needs no other changes.

Which values does the container need?

The container needs two values: the RelayRouter base URL that matches your protocol, and a RelayRouter API key. According to the official relayrouter.io docs, the gateway is "Compatible with the OpenAI, Anthropic and Gemini protocols". Each protocol uses its own base and endpoint:

• OpenAI compatible: base https://relayrouter.io/v1, endpoint POST /v1/chat/completions
• Anthropic compatible: base https://relayrouter.io, endpoint POST /v1/messages
• Gemini compatible: endpoint POST /v1beta/models/{model}:generateContent

Authentication uses the header Authorization: Bearer YOUR_API_KEY. You can create keys at https://relayrouter.io/dashboard. Treat the key as a secret: inject it at runtime through the environment, and do not bake it into the image or commit it to the repository.

How do you configure the Compose file?

You configure the Compose file by defining the values in .env and mapping them to the variable names your SDK reads. The steps below use the OpenAI SDK as an example:

1. Create an API key in the RelayRouter dashboard.
2. Create a .env file containing RELAYROUTER_API_KEY=YOUR_API_KEY and RELAYROUTER_BASE_URL=https://relayrouter.io/v1.
3. Add .env to .gitignore.
4. In docker-compose.yml, under services.app.environment, add OPENAI_API_KEY: ${RELAYROUTER_API_KEY} and OPENAI_BASE_URL: ${RELAYROUTER_BASE_URL}.
5. Run docker compose config to confirm that interpolation resolves. This command prints the resolved values, including the key, so avoid sharing its output.
6. Start the stack with docker compose up -d.

For Anthropic SDKs, map the values to ANTHROPIC_API_KEY and ANTHROPIC_BASE_URL, with the base set to https://relayrouter.io.

Does the application code need to change?

No, the application code does not need to change if it already reads the SDK's standard environment variables. According to the official relayrouter.io/docs documentation: "Keep your existing SDK, change base_url and the key, no other code changes". The SDK picks up the base URL and key from the container environment and sends the Bearer header automatically. Streaming is supported, so code that streams responses keeps working through the gateway. To switch providers, change the model name in your request. Available models include claude-opus-5-5, claude-fable-5-1, claude-opus-5, gpt-6-astra, gpt-5.6-sol and gemini-3.8-flash, plus models from DeepSeek, GLM, MiniMax and Moonshot. The catalog lists about 108 models across 19 public groups. See https://relayrouter.io/docs for protocol details.

How are requests from the container billed?

Requests are billed per model at settlement rates, with a $0 platform fee, no minimum spend and no subscription. Under the published rates, the GPT group settles at CNY 0.6 per $1 of standard usage and the Claude group at CNY 2.0 per $1, compared with a market reference of CNY 6.8 per $1. Some models have direct pricing instead. For example, deepseek-v4-flash costs CNY 1.1 per 1M input tokens and CNY 4.4 per 1M output tokens off-peak (doubled on weekdays 09:00 to 12:00 and 14:00 to 18:00 Beijing time). Failed or errored requests are generally not billed. This means a misconfigured base URL that causes request errors should not add usage charges while you debug your Compose setup. Payment is by Stripe card. Live per-model rates are listed at https://relayrouter.io/models.

FAQ

Can I use env_file instead of environment?

Yes. env_file: .env loads every variable in the file into the container. With this approach, name the variables in the file exactly as your SDK expects, for example OPENAI_API_KEY and OPENAI_BASE_URL.

Which base URL should I use for the Anthropic SDK?

Use https://relayrouter.io. The SDK appends /v1/messages to it. For OpenAI compatible clients, use https://relayrouter.io/v1.

Where do I get the API key?

Create a key at https://relayrouter.io/dashboard, then store it in .env as the value of RELAYROUTER_API_KEY.