OpenRouter.ai is like a marketplace for AI models - it gives you access to tons of different LLMs through one API. Because of this, it is not needed to have subscriptions on multiple AI services, while still having access to their LLM’s via the credit-based model. You only pay what you use, which is very convenient if you want to access LLM’s via API’s through tooling such as N8N or Opencode.
The service basically acts as a middleman - you get one API key that works with dozens of models (GPT, Claude, Llama, etc.) and OpenRouter handles the routing to the right provider. Super handy for testing different models or switching between them without changing your code.