GPT-4o-mini 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-4o-mini and GPT-5 Codex.
GPT-4o-mini
GPT-4o mini is OpenAI's newest model after [GPT-4 Omni](/models/openai/gpt-4o), supporting both text and image inputs with text outputs. As their most advanced small model, it is many multiples more affordable...
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-4o-mini | GPT-5 Codex |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Context Window | 128,000 tokens | 400,000 tokens |
| Agent Suitability | 82/100 | N/A |
| Time to First Token (TTFT) | 150 ms | N/A |
| Deployment Model | managed api | managed api |
| Production Stability | stable | stable |
| API Available | Yes | Yes |
| Released Date | 2024-07-18 | 2025-09-23 |
API Pricing Comparison
Input Price per Million Tokens
GPT-4o-mini
$0.15
GPT-5 Codex
$1.25
Output Price per Million Tokens
GPT-4o-mini
$0.60
GPT-5 Codex
$10.00
Want to test both models live?
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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-4o-mini Quirks & Gotchas
- ▸Ultra-low latency — best TTFT in the OpenAI lineup
- ▸Tool calling limited to single-step — not suitable for complex agentic pipelines
GPT-5 Codex Quirks & Gotchas
No developer gotchas reported.