ai-api
OpenAI API
Frontier models: GPT-5, o-series reasoning, image, audio, embeddings
GPT-5 family, o-series reasoning models, Whisper (audio), DALL-E / gpt-image-1 (image), text-embedding-3, Batch API (50% discount), Realtime API (voice), Assistants, Responses API.
Pricing
| Tier | Price | Notes |
|---|---|---|
| Free Tier (Trial) | Free | $5 free credit for new accounts. Rate-limited. |
| Pay-as-you-go | Free | No monthly min. Per-token pricing by model. |
| Usage Tiers (1-5) | Free | Automatic tier promotion based on cumulative spend. Higher tiers = higher rate limits + new model access. |
| Enterprise | Custom | Custom. Priority access, SLA, dedicated capacity. |
Limits
| Tier | Metric | Value | Notes |
|---|---|---|---|
| — | batch api discount | 50% off all models | Batch API async processing |
| — | context window gpt5 | 272000 tokens | GPT-5 context window (272k input, ~128k output) |
| — | dalle-3 1024 | $0.04/image (standard) | DALL-E 3 1024×1024 |
| — | embedding-3-large | $0.13/M tokens | text-embedding-3-large |
| — | embedding-3-small | $0.02/M tokens | text-embedding-3-small |
| — | function calling | JSON schema-based, parallel calls | Function/tool calling |
| — | gpt-4.1 input | $2.00/M tokens | GPT-4.1 input |
| — | gpt-4.1-nano input | $0.10/M tokens | GPT-4.1 Nano input |
| — | gpt-4.1-nano output | $0.40/M tokens | GPT-4.1 Nano output |
| — | gpt-4.1 output | $8.00/M tokens | GPT-4.1 output |
| — | gpt-5 input | $1.25/M tokens | GPT-5 input |
| — | gpt-5-mini input | $0.25/M tokens | GPT-5 Mini input |
| — | gpt-5-mini output | $2.00/M tokens | GPT-5 Mini output (approx) |
| — | gpt-5-nano input | $0.05/M tokens | GPT-5 Nano input |
| — | gpt-5-nano output | $0.40/M tokens | GPT-5 Nano output |
| — | gpt-5 output | $10.00/M tokens | GPT-5 output |
| — | o3 input | $2.00/M tokens | o3 reasoning input |
| — | o3 output | $8.00/M tokens | o3 reasoning output |
| — | prompt caching | 50% off cached input tokens | Automatic prompt caching |
| — | structured outputs | JSON schema-enforced outputs | Structured Outputs |
| — | tts-1 | $15/M characters | Text-to-Speech |
| — | whisper asr | $0.006/minute | Whisper transcription |
Features
- Assistants API — Stateful assistants with tools, threads, file search. · docs
- Batch API — 50% discount for async processing within 24h. · docs
- Chat Completions API — Classic /v1/chat/completions endpoint. · docs
- Files API — Upload docs for retrieval, fine-tuning, batch.
- Fine-Tuning — Supervised + DPO fine-tuning for GPT-4o, GPT-4.1, GPT-4o-mini. · docs
- Function Calling — JSON-schema tool calling; parallel calls supported. · docs
- Moderation — Safety classifier API (free).
- Prompt Caching — Auto-cache repeated prefixes; 50% cheaper cached hits.
- Realtime API — WebSocket streaming voice + text with low latency. · docs
- Responses API — Stateful conversational API. · docs
- Structured Outputs — Enforced JSON schema compliance.
- Vision — Image input for GPT models.
Developer interfaces
| Slug | Name | Kind | Version |
|---|---|---|---|
| sdk-dotnet | openai-dotnet | sdk | 2.x |
| sdk-go | openai-go | sdk | 1.x |
| mcp | OpenAI MCP | mcp | — |
| sdk-node | openai-node | sdk | 5.x |
| sdk-python | openai-python | sdk | 2.x |
| rest-api | OpenAI REST API | rest | v1 |
| realtime-api | Realtime API (WebSocket) | other | — |
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