Claude Haiku 4.5 vs GPT-5.3-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-5.3-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-5.3-Codex
GPT-5.3-Codex is OpenAI’s most advanced agentic coding model, combining the frontier software engineering performance of GPT-5.2-Codex with the broader reasoning and professional knowledge capabilities of GPT-5.2. It achieves state-of-the-art results...
Technical Specifications
| Specification | Claude Haiku 4.5 | GPT-5.3-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 | 2026-02-24 |
API Pricing Comparison
Input Price per Million Tokens
Claude Haiku 4.5
$1.00
GPT-5.3-Codex
$1.75
Output Price per Million Tokens
Claude Haiku 4.5
$5.00
GPT-5.3-Codex
$14.00
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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-5.3-Codex Quirks & Gotchas
No developer gotchas reported.