Model Comparison
GPT-5.3 CodexLlama 3.1 405B
Let's see who can write code better - GPT-5.3 Codex or Llama 3.1 405B
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
Llama 3.1 405B
Description
Open-source frontier model with 405 billion parameters
Specifications
Context Window128K
Max Output4K
ReleasedJul 2024
API✗
Key Features
Open sourceSelf-hostableTool use supportMultilingualNo usage restrictions
Strengths
- ✓Fully open source
- ✓Can be self-hosted
- ✓Strong performance
- ✓No API costs if self-hosted
Weaknesses
- ✗Requires significant compute
- ✗Complex to deploy
- ✗No official API service
Agent Support
No known agents