OpenAI Response API vs Chat Completions: Which Should You Use for Your Next Build?
Chat Completions vs OpenAI Responses API: What Actually Changed - DEV Community
Migrate to the Responses API | OpenAI API
The Responses API is a unified interface for building powerful, agent-like applications. It contains:
- Built-in tools like web search, file search, computer use, code interpreter, and remote MCPs.
- Seamless multi-turn interactions that allow you to pass previous responses for higher accuracy reasoning results.
- Native multimodal support for text and images.
The Responses API contains several benefits over Chat Completions:
- Better performance: Using reasoning models, like GPT-5, with Responses will result in better model intelligence when compared to Chat Completions. Our internal evals reveal a 3% improvement in SWE-bench with same prompt and setup.
- Agentic by default: The Responses API is an agentic loop, allowing the model to call multiple tools, like
web_search,image_generation,file_search,code_interpreter, remote MCP servers, as well as your own custom functions, within the span of one API request. - Lower costs: Results in lower costs due to improved cache utilization (40% to 80% improvement when compared to Chat Completions in internal tests).
- Stateful context: Use
store: trueto maintain state from turn to turn, preserving reasoning and tool context from turn-to-turn. - Flexible inputs: Pass a string with input or a list of messages; use instructions for system-level guidance.
- Encrypted reasoning: Opt-out of statefulness while still benefiting from advanced reasoning.
- Future-proof: Future-proofed for upcoming models.
