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GPT-5.3 Codex

Multimodal
OpenAI

GPT-5.3 Codex is OpenAI's specialized coding model with extended reasoning capabilities. Supports text and visual input with a 400K token context window.

Key Specifications

Parameters
-
Context
400.0K
Release Date
February 5, 2026
Average Score
71.6%

Timeline

Key dates in the model's history
Announcement
February 5, 2026
Today
March 25, 2026

Technical Specifications

Parameters
-
Training Tokens
-
Knowledge Cutoff
August 31, 2025
Family
-
Capabilities
MultimodalZeroEval

Pricing & Availability

Input (per 1M tokens)
$1.75
Output (per 1M tokens)
$14.00
Max Input Tokens
400.0K
Max Output Tokens
128.0K
Supported Features
Function CallingStructured OutputCode ExecutionWeb SearchBatch InferenceFine-tuning

Benchmark Results

Model performance metrics across various tests and benchmarks

Other Tests

Specialized benchmarks
SWE-Lancer (IC-Diamond subset)
SWE-Lancer IC Diamond. Effort xhighSelf-reported
81.0%
Cybersecurity CTFs
Tasks CTF by Effort xhighSelf-reported
78.0%
Terminal-Bench 2.0
Effort xhigh.Self-reported
77.0%
OSWorld-Verified
Effort xhigh.Self-reported
65.0%
SWE-Bench Pro
SWE-Bench Pro (version). Effort xhighSelf-reported
57.0%

License & Metadata

License
proprietary
Announcement Date
February 5, 2026
Last Updated
March 21, 2026

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