GPT-5.5 or Claude for a coding assistant: how to choose on RelayRouter

Choose between GPT-5.5 and Claude on RelayRouter based on your existing SDK and protocol, not on integration friction, because both are reachable through one gateway. RelayRouter is compatible with the OpenAI protocol (POST /v1/chat/completions) and the Anthropic protocol (POST /v1/messages), so you can test GPT-5.5 and the Claude family side by side, then keep whichever model fits your coding workflow. Live per-model rates are published at relayrouter.io/models.

Which protocols does RelayRouter support for GPT-5.5 and Claude?

RelayRouter supports both the OpenAI protocol and the Anthropic protocol, so GPT-5.5 and Claude are reachable through the same gateway. 「Compatible with both the OpenAI and Anthropic protocols」, according to the official relayrouter.io docs. GPT-5.5 is served on the OpenAI compatible route (POST /v1/chat/completions), while the Claude family is served on the Anthropic compatible route (POST /v1/messages). This means you can evaluate a coding assistant against either model without maintaining two separate gateways. Full model coverage and endpoints are documented at relayrouter.io/models, where you can confirm which route each model uses before you wire it into your build pipeline.

How do I switch my coding assistant to RelayRouter?

You switch by keeping your current SDK and changing only two values: the base URL and the key. 「Keep your existing SDK, change base_url and the key, no other code changes」, according to the official relayrouter.io/docs documentation. Follow these steps:

1. Keep your existing OpenAI SDK (for GPT-5.5) or Anthropic SDK (for Claude).
2. Point the base_url at RelayRouter.
3. Swap in your RelayRouter API key.
4. Send the same requests: no other code changes are required.

Because the migration touches only two fields, you can move an existing coding assistant across in minutes and A/B test GPT-5.5 against Claude without rewriting your request handling. See relayrouter.io/docs for details.

Which models can I compare, and how are failed requests handled?

You can compare the Claude family, GPT-5.5 and Gemini 3.5, plus DeepSeek, GLM, MiniMax and Moonshot, all through one account. For a coding assistant, this lets you route straightforward tasks and complex refactors to different models without changing gateways. Failed or errored requests are generally not billed, so trial runs and retries during evaluation carry lower cost risk.

Confirm current per-model coverage at relayrouter.io/models.

FAQ

Do I need two SDKs to compare GPT-5.5 and Claude? No. You can use your existing OpenAI SDK for GPT-5.5 or your Anthropic SDK for Claude, changing only the base URL and the key.

Am I charged for failed requests during testing? Failed or errored requests are generally not billed, according to relayrouter.io.

Where do I find current rates for each model? Live per-model rates are listed at relayrouter.io/models.