OpenAI: gpt-5.1-codex-mini API
A lightweight version of the GPT-5.1 Codex series released by OpenAI in November 2025. Optimized for daily code completion, minor refactoring, and unit test generation, it demonstrates superior stability and accuracy in following apply_patch instructions, understanding Git diffs, and utilizing developer toolchains compared to the general GPT-5 mini.
- Context window: 400,000 tokens
- Max output: 128,000 tokens
- Input: text, image
- Output: text
- Reasoning: Supported
- Tool calling: Supported
- File input: Supported
- Released: 2025-11-12
- Knowledge cutoff: 2024-09-30
Frequently Asked Questions
What is the context window of gpt-5.1-codex-mini?
gpt-5.1-codex-mini supports a context window of up to 400,000 tokens.
Does gpt-5.1-codex-mini support function calling?
Yes. gpt-5.1-codex-mini supports tool / function calling.
Does gpt-5.1-codex-mini support reasoning?
Yes. gpt-5.1-codex-mini is a reasoning-capable model.
What is the knowledge cutoff of gpt-5.1-codex-mini?
The knowledge cutoff of gpt-5.1-codex-mini is 2024-09-30.