OpenRouter
OpenRouter is a unified API that lets you call 200+ language models through one endpoint with one API key — the de-facto model-router infrastructure layer in 2026.
OpenRouter sits between your application and every major LLM provider (OpenAI, Anthropic, Google, Meta, Mistral, DeepSeek, Together, Fireworks). One API key, one billing relationship, one request format — but you can route to any model at any time. Useful for: A/B testing models, falling back across providers, accessing cheaper open-weight inference, and avoiding vendor lock-in. The trade-off is a small per-token markup and an additional network hop. Major alternatives in 2026: Portkey, Vellum, Martian, LiteLLM (self-host).
When to use openrouter
- Multi-model production stacks.
- Model A/B testing and routing.
- Avoiding single-provider lock-in.
Common mistakes
- Routing through OpenRouter when latency is critical — direct provider calls are slightly faster.
- Treating it as a single SLA — each underlying provider has its own.
FAQ
What is openrouter?
OpenRouter is a unified API that lets you call 200+ language models through one endpoint with one API key — the de-facto model-router infrastructure layer in 2026.
When should I use openrouter?
Multi-model production stacks. Model A/B testing and routing. Avoiding single-provider lock-in.
What are the most common mistakes with openrouter?
Routing through OpenRouter when latency is critical — direct provider calls are slightly faster. Treating it as a single SLA — each underlying provider has its own.
Related terms
- Model router — A model router picks which language model handles each request based on cost, latency, or task type — the standard production pattern in 2026.
- AI agent — An AI agent is a system where a language model autonomously plans and executes a sequence of tool calls to accomplish a goal.
- Function calling (tool use) — Function calling lets a language model emit a structured request to invoke a developer-defined tool, enabling reliable JSON output and agent workflows.
Last updated: 2026-06-01. Raw markdown: https://promtable.com/glossary/openrouter.md.