GPT-5.5 Instant

OpenAI

Fast default ChatGPT model (replaced GPT-5.3 Instant, May 2026). Standalone API pricing not yet published.

Text Generation API GPT Family v5.5

Documentation Back to Models

Parameters

params

Context Window

1.0M

tokens

Max Output

tokens

Input Price

per 1M tokens

Output Price

per 1M tokens

GPT Family 18 models

The full GPT line by generation — pricing and capabilities vary across the family.

GPT-5.5

GPT-5.5 Instant Current

Everyday assistant, low-latency chat

1.0M

context

May 2026

GPT-5.5 Pro

Hardest reasoning, research, complex coding

Agentic workflows, coding, research, data analysis

GPT-5.4

Complex reasoning, research, advanced analysis

General-purpose, reasoning, multimodal, document editing

GPT-5.3

Code generation, software engineering, reasoning

GPT-5

Multimodal reasoning, reduced hallucinations

GPT-5.1

Fast, warm responses, customizable tone

Complex reasoning, persistent problem-solving

GPT-4

Multimodal, fast, versatile

Complex tasks, vision, analysis

Enterprise Azure integration

$2.5 / $10

in / out · 1M

o1 Preview

Complex reasoning, math, code

STEM reasoning, efficient

GPT-3.5

Capabilities

👁️

Vision

⚡

Function Calling

📋

JSON Mode

🌊

Streaming

💬

System Prompt

🖥️

Code Execution

🔍

Web Search

🔌

MCP Support

Details

Release Date: May 5, 2026
Knowledge Cutoff: December 1, 2025
Source: API
API Key Required: Yes
License: Proprietary
Model ID: gpt-5.5-instant

Last updated: May 27, 2026