Switching a Direct OpenAI Client to the Aggregator: Headers, Base URL and Env Vars

Why minimal changes matter

If your application already uses an OpenAI-compatible SDK, you can often switch to an aggregator endpoint by changing just a few configuration values. This reduces the risk of breaking existing code and keeps your integration simple. The aggregator provides an OpenAI-compatible API, so the same SDK methods and request structures generally apply.

What typically stays the same

Most of your application logic remains unchanged:

• Client initialization (e.g., new OpenAI({...}))
• Request payloads (messages, model names, temperature, etc.)
• Response parsing (choices, usage, etc.)
• Error handling patterns
• Streaming or non-streaming modes

The only differences are the endpoint your client points to and how you authenticate.

The three core changes

1. Base URL

Set the base URL to the aggregator's API endpoint. This tells the SDK where to send requests instead of the default OpenAI endpoint. The exact URL is provided in your aggregator dashboard or documentation.

2. API key

Replace your OpenAI API key with an aggregator API key. This key is used for authentication and billing. Keep it secret and never commit it to version control.

3. Optional headers

Some aggregators accept additional headers for routing, logging, or feature flags. These are optional and may include things like a custom User-Agent or a header to select a specific model provider. Check the aggregator's documentation for supported headers. If none are required, you can skip this step.

Environment variable management

Hardcoding credentials and endpoints is risky. Use environment variables instead:

• OPENAIAPIKEY – replace with your aggregator key
• OPENAIBASEURL – set to the aggregator endpoint

If your SDK or framework reads these variables automatically, you may not need to change code at all—just update the values. For example, many OpenAI-compatible clients respect OPENAIBASEURL and OPENAIAPIKEY out of the box.

If you prefer explicit configuration, you can still set them in your client constructor:

const client = new OpenAI({
  apiKey: process.env.AGGREGATOR_API_KEY,
  baseURL: process.env.AGGREGATOR_BASE_URL,
});

Use distinct environment variable names if you need to support both OpenAI and the aggregator simultaneously.

Code example: before and after

Before (direct OpenAI):

const client = new OpenAI({
  apiKey: process.env.OPENAI_API_KEY,
});

After (aggregator):

const client = new OpenAI({
  apiKey: process.env.AGGREGATOR_API_KEY,
  baseURL: process.env.AGGREGATOR_BASE_URL,
});

That's the entire diff in most cases.

Handling model names

The aggregator supports many models (Claude, GPT, DeepSeek, Qwen, GLM, Kimi, etc.). Model identifiers may differ from OpenAI's naming. If you're switching from an OpenAI model to a different provider's model, update the model parameter in your requests. Refer to the aggregator's model list for exact names.

Testing the switch

After making changes, verify that requests succeed:

• Send a simple chat completion request.
• Check the response for expected structure.
• Confirm billing or usage appears in your aggregator dashboard.
• Test error handling (e.g., invalid API key) to ensure your app fails gracefully.

Common pitfalls

• Forgetting to update the base URL – requests still go to OpenAI and fail with invalid key.
• Using the wrong environment variable names – double-check that your code reads the variables you set.
• Model name mismatches – using an OpenAI model name that the aggregator doesn't recognize.
• Leaving old keys in place – remove or rotate old credentials to avoid confusion.

Pricing and credits (conceptual)

With the aggregator, you pay the official model price multiplied by 1.3. If you contribute keys, you receive credits at official price × 1.1 (or × 1.2 for premium) in USDC. This is not a discount on official prices; it's a straightforward markup for the service. No KYC is required, and you can top up with USDC on Base.

Summary

Switching an existing OpenAI SDK app to an aggregator endpoint usually involves only three changes: base URL, API key, and optional headers. Use environment variables for safety, test your integration, and update model names if needed. The rest of your code stays the same.