GPT-5.3 Codex

OpenAI

Coding-specialized GPT-5.3 model. Initially available through Codex app, later released via API. Extended thinking with reasoning capabilities.

Text Generation API GPT Family v5.3
Documentation Back to Models
Parameters
-
params
Context Window
400K
tokens
Max Output
-
tokens
Input Price
$1.7500
per 1M tokens
Output Price
$14.0000
per 1M tokens

GPT Family Timeline 15 versions

GPT-5.4 Latest api
Mar 2026
GPT-5.4 Pro api
Mar 2026
GPT-5.3 Codex Current api
Feb 2026
GPT-5.2 Thinking api
Dec 2025
GPT-5.2 Pro api
Dec 2025
GPT-5.2 Instant api
Dec 2025
GPT-5.1 Instant api
Nov 2025
GPT-5.1 Thinking api
Nov 2025
GPT-5 api
Aug 2025
GPT-4o (Nov 2024) api
Nov 2024
o1 Preview api
Sep 2024
o1 Mini api
Sep 2024
GPT-4 Turbo api
Jan 2024
GPT-3.5 Turbo api
Nov 2023
GPT-4o (Azure) api
-

Capabilities

👁️
Vision
⚡
Function Calling
📋
JSON Mode
🌊
Streaming
💬
System Prompt
🖥️
Code Execution
🔍
Web Search
🔌
MCP Support

Details

Release Date
February 5, 2026
Knowledge Cutoff
August 31, 2025
Source
API
API Key Required
Yes
License
Proprietary
Model ID
gpt-5.3-codex
Last updated: March 13, 2026