# OpenAI API

**Provider:** OpenAI
**Category:** ai
**Base URL:** `https://api.openai.com/v1`
**Auth:** bearer — `Authorization: Bearer sk-proj-...`
**Rate Limit:** 3,500 RPM · 200,000 TPM (Tier 1)
**Free Tier:** No
**Pricing:** Pay per use (pay-as-you-go)
**Docs:** https://platform.openai.com/docs

## Description

OpenAI provides state-of-the-art AI models via a unified REST API. GPT-4o handles text, vision, and audio; o1 excels at advanced reasoning; DALL·E 3 generates and edits images; Whisper transcribes speech; and embedding models power semantic search and retrieval.

## Endpoints

| Method | Endpoint | Description |
|--------|----------|-------------|
| POST | `https://api.openai.com/v1/chat/completions` | Generate chat completions (GPT-4o, o1, etc.) |
| POST | `https://api.openai.com/v1/embeddings` | Create vector embeddings from text |
| POST | `https://api.openai.com/v1/images/generations` | Generate images with DALL·E 3 |
| POST | `https://api.openai.com/v1/images/edits` | Edit existing images using a mask |
| POST | `https://api.openai.com/v1/audio/transcriptions` | Transcribe audio files with Whisper |
| POST | `https://api.openai.com/v1/audio/speech` | Convert text to speech (TTS) |
| GET | `https://api.openai.com/v1/models` | List all available models |

## Authentication

Pass your API key as a Bearer token in the Authorization header. Keys are prefixed with sk-.

```
Authorization: Bearer sk-proj-...
```

## Sample Request

```bash
curl https://api.openai.com/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -d '{
    "model": "gpt-4o",
    "messages": [
      {"role": "system", "content": "You are a helpful assistant."},
      {"role": "user", "content": "Say hello!"}
    ],
    "max_tokens": 100
  }'
```

## Sample Response

```json
{
  "id": "chatcmpl-abc123",
  "object": "chat.completion",
  "model": "gpt-4o-2024-08-06",
  "choices": [{
    "index": 0,
    "message": {
      "role": "assistant",
      "content": "Hello! How can I help you today?"
    },
    "finish_reason": "stop"
  }],
  "usage": {
    "prompt_tokens": 20,
    "completion_tokens": 9,
    "total_tokens": 29
  }
}
```

## Pricing Details

GPT-4o: $2.50/M input, $10/M output. GPT-4.1: $2/M in, $8/M out. GPT-5: $1.25/M in, $10/M out. o3: $2/M in, $8/M out. o4-mini: $1.10/M in, $4.40/M out. GPT-4o mini: $0.15/M in, $0.60/M out. Batch API: 50% off.

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*Source: [API Map](https://apimap.dev/apis/openai/) — CC BY 4.0*