Claude Haiku 4.5 vs GPT-5.1-Codex
How do these models stack up? Below is an expert side-by-side comparison of specifications, context window capacity, live pricing per million tokens, and standardized benchmark scores for Claude Haiku 4.5 and GPT-5.1-Codex.
Claude Haiku 4.5
Claude Haiku 4.5 is Anthropic’s fastest and most efficient model, delivering near-frontier intelligence at a fraction of the cost and latency of larger Claude models. Matching Claude Sonnet 4’s performance...
GPT-5.1-Codex
GPT-5.1-Codex is a specialized version of GPT-5.1 optimized for software engineering and coding workflows. It is designed for both interactive development sessions and long, independent execution of complex engineering tasks....
Technical Specifications
| Specification | Claude Haiku 4.5 | GPT-5.1-Codex |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Context Window | 200,000 tokens | 400,000 tokens |
| Agent Suitability | 87/100 | N/A |
| Time to First Token (TTFT) | 180 ms | N/A |
| Deployment Model | managed api | managed api |
| Production Stability | stable | stable |
| API Available | Yes | Yes |
| Released Date | 2025-10-15 | 2025-11-13 |
API Pricing Comparison
Input Price per Million Tokens
Claude Haiku 4.5
$1.00
GPT-5.1-Codex
$1.25
Output Price per Million Tokens
Claude Haiku 4.5
$5.00
GPT-5.1-Codex
$10.00
Want to test both models live?
Run side-by-side prompt prompts in our dynamic Sandbox. Check execution speeds, latency metrics, and compute actual costs in real-time.
Benchmark Performance Metrics
Scores show the raw performance percentages verified across key evaluation suites. Higher bars indicate superior accuracy and capability in that domain.
Claude Haiku 4.5 Quirks & Gotchas
- ▸Fastest TTFT in the Claude lineup — ideal for real-time chat
- ▸Tool calling limited compared to Sonnet — best for simple classification and routing
GPT-5.1-Codex Quirks & Gotchas
No developer gotchas reported.