GPT-5.3-Codex
ModelActiveby OpenAI · family “gpt-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... (description from the OpenRouter listing)
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Epoch Capabilities Index
156.8 #16 of 268
90% CI 153.8 – 160.4
Released
5 Feb 2026
Context window
400K tokens
Max output
128K tokens
Input $ / 1M tokens
$1.75
Output $ / 1M tokens
$14.0
Cached input $ / 1M
$0.17
Each benchmark shown separately with its own source
Benchmark results (4)
| Benchmark | Domain | Score | vs best recorded | Setting | Run | Source |
|---|---|---|---|---|---|---|
| Terminal Bench | agents | 78.4% ±2.2 | 93% | agent: SageAgent | 5 Feb 2026 | External ↗ |
| METR Time Horizons | agents | 74.5% | 87% | — | — | External ↗ |
| WeirdML | coding | 79.3% | 85% | — | — | External ↗ |
| SWE-Bench verified | coding | 74.8% ±2.0 | 90% | high | 25 Feb 2026 | Eval log ↗ |
Source: Epoch AI Benchmarking Hub (CC BY 4.0). “External” rows are leaderboard results Epoch collects from third parties. Best reported setting per benchmark is shown.
API list price over time
Price history
$ per 1M tokens
8 recorded prices on 3 Mar 2026 (OpenRouter listing + Internet Archive snapshots); re-read on every data refresh, most recently 3h ago. Steps show when the price changed.
Events
- Model launchMajorOpenAI releases GPT-5.3-CodexEpoch AI Benchmarking Hub