gpt-5.1

GPT 5.1

gpt-5.1
GPT-5.1 is a next-generation large language model that delivers high-fidelity understanding, richer context handling, improved instruction fidelity and deeper reasoning.
Reasoning
Speed
Price
$1.00 • $8.00
Input
Output

GPT-5.1 built for both conversational use-cases and multi-step agentic workflows, it supports long-context inputs, fine control over style/voice, and robust tool/function invocation.

400000 context window
100000 max output tokens
knowledge cutoff
Reasoning token support

Modalities

Text

Input and output

Image

Input only

Audio

Not supported

Video

Not supported

Endpoints

Chat Completions

v1/chat/completions

Responses

v1/responses

Realtime

v1/realtime

Assistants

v1/assistants

Batch

v1/batch

Fine-tuning

v1/fine-tuning

Embeddings

v1/embeddings

Image generation

v1/images/generations

Videos

v1/videos

Image edit

v1/images/edits

Speech generation

v1/audio/speech

Transcription

v1/audio/transcriptions

Translation

v1/audio/translations

Moderation

v1/moderations

Completions (legacy)

v1/completions

Features

Streaming

Supported

Function calling

Supported

Structured outputs

Supported

Fine-tuning

Supported

Distillation

Not supported