OpenAI API

Overview The OpenAI API is the developer facing product behind ChatGPT — the same GPT 5 family of models, exposed as HTTPS endpoints with per token pricing, first party SDKs in eight languages, and a batteries included platform for embeddings, image generation, speech, moderation, and agentic tool use. If you have shipped anything with a generative feature in the last three years, there is a good chance the first line of production code you wrote called openai.chat.completions.create(). OpenAI built the API before it built ChatGPT — the /v1/completions endpoint predates the consumer chatbot by two years — and that lineage still shows in how the platform is priced, documented, and versioned. The pricing philosophy is "cheap enough to prototype, priced to scale": GPT 5 nano exists precisely so a hackathon project doesn't burn through a $50 credit in an afternoon, and GPT 5 flagship exists so the same project can graduate to production without switching providers. The one line positioning: the OpenAI API is the safest first pick for any team shipping a generative feature in 2026 — the widest model catalog, the most mature SDK ecosystem, the deepest documentation, and the tightest integration with the tools and habits developers already have. It is not always the cheapest per token option and not always the fastest per request, but the ratio of engineering hours saved to dollars spent is still the best in the category for most teams. Under the hood the API surface splits into six product lines: chat…