OpenAI: GPT-5.4 Pro API

GPT-5.4 pro uses more compute to think harder and provide consistently better answers. GPT-5.4 pro is available in the Responses API only to enable support for multi-turn model interactions before responding to API requests, and other advanced API features in the future. Since GPT-5.4 pro is designed to tackle tough problems, some requests may take several minutes to finish. To avoid timeouts, try using background mode. GPT-5.4 pro supports reasoning.effort: medium, high, xhigh.

Frequently Asked Questions

What is the context window of GPT-5.4 Pro?

GPT-5.4 Pro supports a context window of up to 1,050,000 tokens.

Does GPT-5.4 Pro support function calling?

Yes. GPT-5.4 Pro supports tool / function calling.

Does GPT-5.4 Pro support reasoning?

Yes. GPT-5.4 Pro is a reasoning-capable model.

What is the knowledge cutoff of GPT-5.4 Pro?

The knowledge cutoff of GPT-5.4 Pro is 2025-08-30.