OpenAI Responses API vs OpenAI Codex
A side-by-side comparison to help you choose the right tool.
87
OpenAI Responses API scores higher overall (87/100)
But the best choice depends on your specific needs. Compare below.
| Feature | OpenAI Responses API | OpenAI Codex |
|---|---|---|
| Our score | 87 | 86 |
| Pricing | Usage-based API pricing; costs depend on the models and tools you use. | Access depends on OpenAI product plan or API usage; advanced agent access is concentrated in higher tiers and previews. |
| Free plan | No | Yes |
| Best for | Product teams building assistants or agents on OpenAI, Developers migrating from older endpoint patterns, Apps that need streaming and tool invocation in one API | Developers who want AI to work more directly on real code tasks, Teams exploring terminal-first coding agents, Engineers already invested in OpenAI's ecosystem |
| Platforms | api | web, mac, windows, linux, api |
| API | Yes | Yes |
| Languages | en | en |
| Pros |
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| Cons |
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| Visit site | Visit site |
- Pricing
- Usage-based API pricing; costs depend on the models and tools you use.
- Free plan
- No
- Best for
- Product teams building assistants or agents on OpenAI, Developers migrating from older endpoint patterns, Apps that need streaming and tool invocation in one API
- Platforms
- api
- API
- Yes
- Languages
- en
- Pricing
- Access depends on OpenAI product plan or API usage; advanced agent access is concentrated in higher tiers and previews.
- Free plan
- Yes
- Best for
- Developers who want AI to work more directly on real code tasks, Teams exploring terminal-first coding agents, Engineers already invested in OpenAI's ecosystem
- Platforms
- web, mac, windows, linux, api
- API
- Yes
- Languages
- en
87Choose OpenAI Responses API if:
- You are Product teams building assistants or agents on OpenAI
- You are Developers migrating from older endpoint patterns
- You are Apps that need streaming and tool invocation in one API
86Choose OpenAI Codex if:
- You are Developers who want AI to work more directly on real code tasks
- You are Teams exploring terminal-first coding agents
- You are Engineers already invested in OpenAI's ecosystem
- You want to start free
FAQ
- What is the difference between OpenAI Responses API and OpenAI Codex?
- OpenAI Responses API is openai's newer response-oriented api surface for building assistants and agents with streaming, tools, and model control. OpenAI Codex is openai's coding agent experience for writing, editing, understanding, and operating on codebases with a more agentic workflow.
- Which is cheaper, OpenAI Responses API or OpenAI Codex?
- OpenAI Responses API: Usage-based API pricing; costs depend on the models and tools you use.. OpenAI Codex: Access depends on OpenAI product plan or API usage; advanced agent access is concentrated in higher tiers and previews.. OpenAI Codex has a free plan.
- Who is OpenAI Responses API best for?
- OpenAI Responses API is best for Product teams building assistants or agents on OpenAI, Developers migrating from older endpoint patterns, Apps that need streaming and tool invocation in one API.
- Who is OpenAI Codex best for?
- OpenAI Codex is best for Developers who want AI to work more directly on real code tasks, Teams exploring terminal-first coding agents, Engineers already invested in OpenAI's ecosystem.