Discover/AI APIs & Developer Services/OpenAI API

OpenAI API

by OpenAI

Save Open OpenAI API

The Launchpad take

Verdict

GPT models, embeddings, whisper, TTS via API

Chat completions; embeddings; image generation; text-to-speech; vision; fine-tuning; assistants

Best for

DevelopersstartupsenterprisesAI product buildersresearchers

Quick facts

Free tier: Free: $5 initial credits (new accounts); rate-limited; GPT-4o-mini free tier
Starting price: $2.50/$10 per 1M tokens)
Platforms: api
Company: OpenAI

Ready to try OpenAI API? Start with the getting-started guide.

Pricing

Plan	Price
Pay-per-token (GPT-4o	$2.50/$10 per 1M tokens)

Key capabilities

Works with

Text
images
audio
embeddings
code

Outputs

JSON API responses
streaming
images
audio files

API pricing

Decisions API (GPT-6 Luna), USD per 1M tokens: $0.10 input, $0.01 cached input. You only pay for input tokens; there are no output-token charges.

Decisions API only. Other OpenAI API models are priced on OpenAI's pricing page.

Features

Decisions API: generally available 2026-10-22, runs on GPT-6 Luna via its own Decisions endpoint. It answers questions with bounded answers, returning a probability, a choice or a score, with up to 400 questions per request. Regional processing is available in the US and EU.

Get it

How to use OpenAI API on phones and tablets.

Mobile web: Works in a mobile browser (responsive or dedicated mobile site).

Technical details

Offline: No
API: Yes
Languages: Multilingual (100+ languages)
Difficulty: Beginner-friendly
Privacy: High
Time to productivity: 1 hour
Upgrade when: Credit exhaustion; higher rate limits; access to newest models; batch API; fine-tuning
Integrations: Every major framework: LangChain, LlamaIndex, Vercel AI SDK, Zapier
more
Make, n8n, 1000s of tools

What changed

2026-10-26 · features — Added the Decisions API (generally available 2026-10-22, GPT-6 Luna, its own endpoint) and its input-only token prices.
2026-10-14 · models — Recorded GPT-6 Astra as the API flagship, GPT-6.1 Sol for balanced cost, and GPT-6 Luna for high-volume work.

Models

Last verified Oct 24, 2026. Figures that could not be confirmed on an official vendor page are marked unverified — we do not guess.

Full GPT (ChatGPT / OpenAI) comparison

Which one should I use?

In the ChatGPT app, what you can pick depends on the plan. OpenAI’s help center: GPT-6 Pro (powered by GPT-6 Astra) is on Pro, Business, and Enterprise; Plus gets Astra in ChatGPT Work and Codex, not as GPT-6 Pro in regular Chat. Free and Go do not get Astra.
For API work, OpenAI currently tells developers to start with GPT-6 Astra for hard jobs, GPT-6.1 Sol when you want similar quality for less money, and GPT-6 Luna for cheap high-volume work.
GPT-5.5 is the previous flagship. Use it only if your API work already depends on it.

GPT-6 Astra

Current

Context: 1.05M
Max output: 128K
API input / 1M: $10 / 1M
API output / 1M: $50 / 1M

Best for: Paid ChatGPT users and API developers with the hardest work — research, long coding, and multi-step computer use.

ChatGPT Plus: Astra in Work and Codex. Pro $100/$200, Business, and Enterprise: GPT-6 Pro in Chat (workspace permissions may apply). Not on Free or Go.

Source: GPT-6 Astra model page

GPT-6.1 Sol

Current

Context: 1.05M
Max output: 128K
API input / 1M: $2 / 1M
API output / 1M: $10 / 1M

Best for: API and ChatGPT Work/Codex users who want strong results without Astra’s price.

OpenAI help: GPT-6.1 Sol is a ChatGPT Work and Codex model, not regular Chat. It is rolling out on eligible paid plans; exact plan list depends on rollout and workspace settings.

Source: GPT-6.1 Sol model page

GPT-6 Sol

Current

Context: 1.05M
Max output: 128K
API input / 1M: $2 / 1M
API output / 1M: $10 / 1M

Best for: Existing API work built on GPT-6 Sol; new work should start on GPT-6.1 Sol.

OpenAI's ChatGPT docs list GPT-6 Sol for ChatGPT Work and Codex on paid plans. OpenAI's pages disagree on whether it also powers regular Chat, so check your model picker.

Source: GPT-6 Sol model page

GPT-6 Luna

Current

Context: 1.05M
Max output: 128K
API input / 1M: $0.1 / 1M
API output / 1M: $0.5 / 1M

Best for: Lots of short, cheap jobs — classification, drafts, and bulk API calls.

OpenAI help: GPT-6 Luna is a ChatGPT Work and Codex model, not regular Chat. Free/Go ChatGPT model names in the main Chat picker are a separate list (unverified here beyond the GPT-6 help article).

Source: GPT-6 Luna model page

GPT-5.5

Prior gen

Context: 1.05M
Max output: 128K
API input / 1M: $5 / 1M
API output / 1M: $30 / 1M

Best for: Existing API integrations that are not ready to move to GPT-6.

Retired from ChatGPT, ChatGPT Work and Codex on 14 Oct 2026. API access is unaffected.

Source: GPT-5.5 model page

Version	Context	Max out	API in / 1M	API out / 1M	Source
GPT-6 Astra Current`gpt-6-astra`	1.05M	128K	$10 / 1M	$50 / 1M	GPT-6 Astra model page
GPT-6.1 Sol Current`gpt-6.1-sol`	1.05M	128K	$2 / 1M	$10 / 1M	GPT-6.1 Sol model page
GPT-6 Sol Current`gpt-6-sol`	1.05M	128K	$2 / 1M	$10 / 1M	GPT-6 Sol model page
GPT-6 Luna Current`gpt-6-luna`	1.05M	128K	$0.1 / 1M	$0.5 / 1M	GPT-6 Luna model page
GPT-5.5 Prior gen`gpt-5.5`	1.05M	128K	$5 / 1M	$30 / 1M	GPT-5.5 model page

Sources & notes(2)

API pricing: https://openai.com/index/decisions-api
Models: https://developers.openai.com/api/docs/models

Alternatives

Anthropic API

by Anthropic

Claude models via API

No free planBeginner-friendlyWeb

Good for AI APIs & Developer Services

Free-plan details

No ongoing free API tier: you pay per token used. Anthropic's pricing docs say new users receive a small amount of free credits to test the API. The free Claude chat plan is a separate product (see the Claude listing).

Paid options: $0.10 input / $0.50 output per million tokens

Source · checked 2026-10-26 · unverified ↗Pricing source · checked 2026-10-25 ↗Meet the tool