gpt-5-nano

As the smallest and fastest member of the GPT-5 system, this model is positioned as a lightweight successor to GPT-4.1-nano. Its practical focus is developer tooling, rapid interactions, and latency-sensitive applications where strong instruction following matters more than the deeper reasoning available from larger variants.

The model is well suited to real-time assistants, cost-conscious applications, structured workflows, tool use, and image-informed tasks. A substantial context window supports work with large inputs, while reasoning, attachments, tool calling, and structured output make it useful for agentic and multi-step developer experiences. The supplied evidence does not establish specific benchmark scores, parameter counts, or training methods.