DeepSeek Reasoner

DeepSeek Reasoner is a specialized API model designed for complex math, coding, and logical tasks using an explicit, visible Chain of Thought.

DeepSeek Reasoner (accessed via the deepseek-reasoner model identifier) is built for developers who need high-precision logical processing without the steep price tag of traditional reasoning models. Operating on an OpenAI-compatible API format, the model outputs an explicit Chain of Thought (CoT) before delivering its final response, allowing users to inspect the system's step-by-step thinking process. With a massive 1M-token context window and competitive pricing ($0.14 per million input tokens and $0.28 per million output tokens), it delivers top-tier performance on complex mathematical proofs, code generation, and scientific reasoning tasks.

https://api-docs.deepseek.com/guides/reasoning_model