7 best unified LLM API providers in 2026

A unified LLM API streamlines access to multiple language model providers like OpenAI, Anthropic, and Google by routing requests through a single integration point, eliminating the need for separate SDKs, authentication, and billing systems. This setup allows developers to easily switch between models using parameters, simplifying the process of adding or testing new models without altering existing client setups. The choice of a unified LLM API provider often hinges on factors such as compatibility with OpenAI SDK, provider and model breadth, caching capabilities, cost visibility, observability, and the level of control over deployment and vendor lock-in. Notably, Braintrust Gateway is highlighted as a leading provider, offering extensive model access, evaluation, and debugging tools, making it suitable for production AI teams that require robust model management and quality control. Other providers like OpenRouter, Vercel AI Gateway, LiteLLM, Portkey, Together AI, and Groq cater to different needs, ranging from broad model access and governance controls to low-latency inference and open-model support.