GPT-5.6 Terra vs GPT-5 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 GPT-5.6 Terra and GPT-5 Codex.
GPT-5.6 Terra
GPT-5.6 Terra is a balanced model in OpenAI's GPT-5.6 series, positioned between the flagship Sol tier and the cost-efficient Luna tier. It is suited for everyday coding, reasoning, and agentic...
GPT-5 Codex
GPT-5-Codex is a specialized version of GPT-5 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 | GPT-5.6 Terra | GPT-5 Codex |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Context Window | 1,050,000 tokens | 400,000 tokens |
| Agent Suitability | N/A | N/A |
| Time to First Token (TTFT) | N/A | N/A |
| Deployment Model | managed api | managed api |
| Production Stability | beta | stable |
| API Available | Yes | Yes |
| Released Date | 2026-07-09 | 2025-09-23 |
API Pricing Comparison
Input Price per Million Tokens
GPT-5.6 Terra
$2.50
GPT-5 Codex
$1.25
Output Price per Million Tokens
GPT-5.6 Terra
$15.00
GPT-5 Codex
$10.00
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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.
GPT-5.6 Terra Quirks & Gotchas
No developer gotchas reported.
GPT-5 Codex Quirks & Gotchas
No developer gotchas reported.