Model Comparison
GPT-5.3 CodexOpenAI o3
Let's see who can write code better - GPT-5.3 Codex or OpenAI o3
Model Information
GPT-5.3 Codex
Description
Next-generation coding-optimized model from OpenAI with enhanced autonomous development capabilities
Specifications
Context Window272K
Max Output33K
ReleasedFeb 2026
API✓
Pricing (per 1M)
In / Out
$1.5/ $12
Key Features
Advanced autonomous codingEnhanced code reviewMulti-step reasoningFull-stack development
Strengths
- ✓State-of-the-art coding benchmarks
- ✓Superior autonomous task completion
- ✓Excellent code review capabilities
- ✓Large context window
Weaknesses
- ✗Premium pricing
- ✗Optimized for coding over general tasks
Agent Support
No known agents
OpenAI o3
Description
Next generation reasoning model
Specifications
Context Window200K
Max Output100K
ReleasedMar 2025
API✓
Pricing (per 1M)
In / Out
$2/ $8
Key Features
Enhanced reasoningImproved capabilitiesBetter performance
Strengths
- ✓State-of-the-art reasoning
- ✓Improved over o1
- ✓Better efficiency
Weaknesses
- ✗Not yet released
- ✗Specifications unknown