OpenAI API
LLM / image / audioMidGPT models, image generation, realtime voice and embeddings via one API.
What it is
OpenAI's developer platform exposes the GPT family plus image, audio, video and embedding models through a unified REST/SDK interface. It covers text generation, function/tool calling, structured outputs, the Realtime voice API, gpt-image generation and agent tooling. Billing is pay-as-you-go per token with cached-input and batch discounts.
What it can do
- Flagship + mini/nano GPT models, large context
- Function calling, tool use, structured (JSON) outputs
- gpt-image generation and editing
- Realtime API for speech-to-speech voice agents
- Embeddings for search and RAG
- Batch API (~50% cheaper) and prompt caching
- Sora video generation
- Built-in agent tools (web search, code interpreter)
Pricing
Free tier
No standing free tier; small trial credits for new accounts
Paid from
pay-as-you-go, from ~$0.20 / 1M tokens
Similar services
| Service | How it differs |
|---|---|
| OpenAI APIpay-as-you-go, from ~$0.20 / 1M tokens | GPT models, image generation, realtime voice and embeddings via one API. |
| Anthropic Claude | Closest frontier rival; strong on coding, long context, agents. |
| Google Gemini | Cheaper multimodal, large free tier, native image and TTS. |
| OpenRouter | One API that routes to OpenAI, Anthropic, Google and open models. |