# DeepSeek

Low-cost reasoning and coding models with V4 API options

Chinese AI research lab developing low-cost reasoning and coding models with a fast-moving hosted API surface. Current API docs foreground DeepSeek V4 Flash and V4 Pro with thinking/non-thinking modes, OpenAI- and Anthropic-compatible endpoints, 1M context, JSON output, tool calls, and chat-prefix/FIM options. Free chat assistant and API access are available, while open-weight/self-hosting claims should be checked against current model repositories.

DeepSeek-native terminal coding agent with a Go rewrite and MCP support

Reasonix is an open-source terminal coding agent built around DeepSeek workflows, with a newer Go-based 1.0 line, MCP integration, repository-aware code understanding, and BYOK model usage. It fits developers who want a DeepSeek-first CLI agent rather than a Claude- or OpenAI-native workflow.