GPT-5.3 Codex

by OpenAI · chat

GPT-5.3 Codex is OpenAI's most capable agentic coding model, combining frontier coding with reasoning capabilities. It supports configurable reasoning effort and is optimized for long-running agentic tasks.

Pricing

Input: .6275/M tokens · Output: 3.02/M tokens

Capabilities

Vision, Function Calling, JSON Mode, Streaming, Reasoning

Context: 400K tokens

Max output: 128K tokens

Routes: 2/2 healthy