OpenAI

GPT-5.3 Codex

OpenAI's best agentic coding model. 77.3% Terminal-Bench, 25% faster than GPT-5.2. Specialized for autonomous code generation and debugging.

4.8/ 5.0
256K context
Try GPT-5.3

Pricing

$20/month
Pro plan
API Pricing
Input$5/1M tokens
Output$15/1M tokens

Ratings

Overall
4.8
Coding
4.9
Writing
4.6
Reasoning
4.8
Speed
4.7
Value
4.6

Pros

  • 77.3% Terminal-Bench — top agentic coding
  • 25% faster than GPT-5.2
  • 256K context window
  • Excellent code debugging
  • Strong multi-language support

Cons

  • Behind Claude Opus 4.6 on SWE-bench
  • No free tier for Codex model

Benchmark Results

Terminal-Bench 2.0
77.3%#1
SWE-bench Verified
75.2%#3

Best For

Agentic coding, fast code generation, multi-language development

Quick Info

Provider
OpenAI
Version
5.3
Released
Feb 2026
Context
256K tokens

Features

Vision/Images
Audio
Video
PDF Processing
Code Generation
AI Agents

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Frequently Asked Questions

Is GPT-5.3 Codex worth it in 2026?

With a rating of 4.8/5, GPT-5.3 Codex is best for Agentic coding, fast code generation, multi-language development. At $20/mo, it's competitive for its feature set.

What are the best alternatives to GPT-5.3 Codex?

Top alternatives include OpenClaw, Claude Opus 4.5, Claude Sonnet 4.5, and GPT-5.1 Instant. Each has different strengths — use our comparison tool above to see detailed head-to-head matchups.

Does GPT-5.3 Codex have a free plan?

GPT-5.3 Codex does not currently offer a free plan. Plans start at $20/mo.