What is the difference between using the Deepseek API directly and using OpenRouter or ThreeRouter?

Deepseek direct offering gives you the most current model versions, first access to new features, and the clearest legal path under Deepseek own DPA. OpenRouter gives you model routing flexibility and a single billing relationship across multiple providers. For production EU workloads, Deepseek direct is the lower-risk choice because the DPA is more mature. OpenRouter and ThreeRoutersuits experimentation or architectures that require fallback to non-Deepseek models.