← All APIs
OpenAI API logo

OpenAI API

OpenAI API

Degradedmachine-learningby OpenAI

OpenAI API provides large language models (GPT-4 / o1 / o3), DALL-E image generation, Whisper speech recognition, embeddings, and other AI capabilities.

Visit site ↗Health checked 9h ago
Use it when

Strongest general-purpose LLM (GPT-4, o1/o3 reasoning)

Watch for

Not cheap (GPT-4o $5-15/M tokens)

First check

Create API key at platform.openai.com. POST https://api.openai.com/v1/chat/completions with model + messages.

Auth
—
CORS
No
HTTPS
Yes
Signup
?
Latency
262 ms
Protocol
REST
Pricing
—

Uptime · 30-day window

Probes: 1Uptime: 0%Avg latency: 262ms
01

About this API

OpenAI API is the de-facto standard of the LLM era — after ChatGPT's explosion, developers worldwide first turned to OpenAI for AI apps. Models cover: GPT family (GPT-3.5, GPT-4, GPT-4o general-purpose), o1/o3 (reasoning models for math and complex reasoning), DALL-E (image generation), Whisper (speech-to-text), TTS (text-to-speech), Embeddings (vectorization for RAG), Moderation (content moderation). API design has shaped the industry — many competitor APIs (Anthropic, Together, Groq, local Ollama) provide OpenAI-compatible endpoints; developers switch providers by only changing base_url. Biggest pain points are pricing and rate limits — GPT-4o input $5/M tokens, output $15/M; high-volume apps cost thousands to tens of thousands monthly. Mainland China developers access via Azure OpenAI Service (compliance version).

02

What you can build

  • 1ChatGPT-style chatbots
  • 2Code generation and completion (Copilot-style)
  • 3Content generation (copy, emails, docs)
  • 4Semantic search (embeddings)
  • 5Image generation (DALL-E)
  • 6Speech-to-text (Whisper)
03

Strengths & limitations

Strengths

  • Strongest general-purpose LLM (GPT-4, o1/o3 reasoning)
  • Richest ecosystem (most SDKs, tools, frameworks)
  • Mature function calling and structured output

Limitations

  • Not cheap (GPT-4o $5-15/M tokens)
  • Strict rate limits
  • Mainland China access requires proxy
04

Example request

Generic template — replace <endpoint> with the real path from the docs.
curl https://openai.com/<endpoint>
05

Getting started

Create API key at platform.openai.com. POST https://api.openai.com/v1/chat/completions with model + messages.

06

FAQ

GPT-4o vs. o1?+

General tasks (chat, generation, function calling): GPT-4o. Deep reasoning (math, complex logic): o1/o3. Latter is expensive and slow but more accurate.

How to reduce token costs?+

Use prompt caching (repeated prompts auto 50% off), batch API (async 50% off), prompt optimization, choose mini models.

Does it work in mainland China?+

Direct access to api.openai.com is blocked. Use Azure OpenAI Service (Microsoft global edition, enterprise accounts) or compliance proxies.

07

Technical details

CORS: NoHTTPS: YesSignup: ?Open source: No
Auth type
unknown
Pricing
unknown
Protocols
REST
SDKs
python, javascript, typescript, go, java, csharp
Response time
262 ms
Last health check
5/12/2026, 7:37:59 AM
08

Tags

aiopenaigptllmchatgpt