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OpenAI API
Developer API for programmatic access to OpenAI reasoning, language, and multimodal models.
What it is
The OpenAI API is a developer platform that provides cloud endpoints for integrating models into software applications, as shown on the OpenAI developers portal. The OpenAI API documentation covers models, agents, tools, and audio and voice, which teams use to add generative features to software.
When it fits
OpenAI API fits web builders and software companies seeking to add generative capabilities, conversational agents, or automated content processing to their products without running models on their own hardware. The documentation describes agents that run on hosted infrastructure and tools that connect models to data.
What to watch
The platform uses a usage-based pricing model calculated per million tokens, with separate rates for input and output processing as outlined on the OpenAI API pricing reference. API calls are subject to organization-level and model-level rate limits measured in requests per minute and tokens per minute, as detailed in the OpenAI rate limits guide. When a 429 response includes a Retry-After header, wait at least that many seconds before retrying, as the OpenAI rate limits guide describes.
- Developers building generative AI features, autonomous agents, and conversational interfaces into web applications.
- Engineering teams seeking hosted model endpoints with structured outputs and tool calling capabilities.
- The OpenAI API gives programmatic access to models, agents, tools, and audio and voice features.Source: developers.openai.com · checked Nov 2026
- Usage is billed on a per-million token basis with distinct rates for input and output tokens.Source: developers.openai.com · checked Nov 2026
- API requests are constrained by organizational rate limits covering requests per minute and tokens per minute per model.Source: developers.openai.com · checked Nov 2026
- When an organization reaches a hard spend limit, affected API requests return HTTP 429 errors.Source: developers.openai.com · checked Nov 2026