Claude Opus 4.8 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 Opus 4.8 and GPT-5.3-Codex.
Claude Opus 4.8
Claude Opus 4.8 is Anthropic's most capable generally available model in the Opus family. It supports text, image, and file inputs with text output, with reasoning support and a 1M-token...
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 Opus 4.8 | GPT-5.3-Codex |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Context Window | 1,000,000 tokens | 400,000 tokens |
| Agent Suitability | 97/100 | N/A |
| Time to First Token (TTFT) | 520 ms | N/A |
| Deployment Model | managed api | managed api |
| Production Stability | beta | stable |
| API Available | Yes | Yes |
| Released Date | 2026-05-27 | 2026-02-24 |
API Pricing Comparison
Input Price per Million Tokens
Claude Opus 4.8
$5.00
GPT-5.3-Codex
$1.75
Output Price per Million Tokens
Claude Opus 4.8
$25.00
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 Opus 4.8 Quirks & Gotchas
- ▸Best-in-class for autonomous code repair and multi-agent orchestration
- ▸Preview model — API may introduce breaking changes without notice
GPT-5.3-Codex Quirks & Gotchas
No developer gotchas reported.