OpenAIText Generation/v1/ai/chatReasoning

GPT-5.6 Luna Pro API

Access GPT-5.6 Luna Pro through one API key. OpenAI GPT-5.6 Luna Pro Reasoning Mode.

GPT-5.6 Luna Pro is the same underlying model as GPT-5.6 Luna, served with OpenAI's reasoning mode set to pro. Use GPT-5.6 Luna Pro for the steps where correctness is worth the wait — final reviews, hard debugging, planning — and plain GPT-5.6 Luna for the rest.

Full Docs Get API Key

Takes 30 seconds.

GPT-5.6 Luna Pro API pricing

Pay per request from your YepAPI balance — no subscription, no monthly minimum. Prices updated September 27, 2026.

Token type	Price
Input	$0.30 / 1M tokens
Output (incl. reasoning)	$1.77 / 1M tokens
Context window	1.1M tokens

What it costs	Per job	Per 1,000
Chat reply1K input + 500 output tokens	$0.0012	$1.19
RAG answer8K input + 800 output tokens	$0.0038	$3.82
Agent step with tools30K input + 2K output tokens	$0.013	$12.54
Long document summary100K input + 2K output tokens	$0.034	$33.54

4,900+

Developers

2.3M+

API calls served

184

Endpoints

$0.01

Per call

Yep, that's it.

Try it live

Send a message and see GPT-5.6 Luna Pro respond in real time.

POST/v1/ai/chatopenai/gpt-5.6-luna-pro

Message *

Max Tokens

Maximum tokens in the response.

Stream

Real-time tokens

Hit "Send Request" to see the response

GPT-5.6 Luna Pro specs

Provider	OpenAI
Model ID	openai/gpt-5.6-luna-pro
Endpoint	/v1/ai/chat
Type	Text Generation
Context window	1.05M tokens
Max output	128K tokens
Reasoning	Yes
OpenAI-compatible	Yes — /v1/ai/chat/completions

How to get a GPT-5.6 Luna Pro API key

1
Create an account
Sign up at yepapi.com with Google or email. It takes about 30 seconds.
2
Create an API key
Open the dashboard, go to API Keys and create a key. Copy it — it starts with yep_sk_.
3
Call GPT-5.6 Luna Pro
Send a request to /v1/ai/chat with the x-api-key header and model "openai/gpt-5.6-luna-pro".
4
Pay as you go
Usage is billed per request from your balance. Top up any amount; there is no subscription.

Strengths

✓

Pro reasoning mode

Identical weights to GPT-5.6 Luna, with reasoning mode fixed to pro.

✓

Same per-token price

Billed at the same rate as GPT-5.6 Luna; you pay for the additional reasoning tokens.

✓

1M token context, 128K output

Handles up to 1,050,000 input tokens and returns up to 128,000 output tokens per call.

✓

Tools and structured output

Function calling, JSON schema outputs and seeds, as on the base model.

Quick start

Copy this snippet and start making calls with GPT-5.6 Luna Pro.

const res = await fetch('https://api.yepapi.com/v1/ai/chat', {
  method: 'POST',
  headers: {
    'x-api-key': 'YOUR_API_KEY',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    "model": "openai/gpt-5.6-luna-pro",
    "messages": [
      {
        "role": "user",
        "content": "Explain API gateways in 2 sentences."
      }
    ],
    "maxTokens": 256
  }),
});
const { data } = await res.json();
console.log(data.message.content);

GPT-5.6 Luna Pro vs similar models

Every model below runs on the same API key — switch by changing the model ID.

Model	Provider	Price	Context
GPT-5.6 Luna Pro	OpenAI	$0.30 in / $1.77 out per 1M	1.1M
GPT-6 Luna	OpenAI	$0.15 in / $0.74 out per 1M	1.1M
GPT-6 Luna Pro	OpenAI	$0.15 in / $0.74 out per 1M	1.1M
GPT-4o Mini	OpenAI	$0.22 in / $0.89 out per 1M	128K
GPT-OSS 120B	OpenAI	$0.22 in / $0.89 out per 1M	131K
GPT-5.6 Luna	OpenAI	$0.30 in / $1.77 out per 1M	1.1M
Nemotron 3 Super	NVIDIA	$0 in / $0 out per 1M	262K
Qwen3.7 Flash	Qwen	$0.04 in / $0.19 out per 1M	1M

Why use GPT-5.6 Luna Pro through YepAPI?

✓One API key for all models — no separate accounts

✓OpenAI SDK compatible — just change the base URL

✓No monthly minimums — pay per token

✓Switch models with one line of code

✓Full provider passthrough — citations, search results, and all extras included

✓Streaming and non-streaming support on every model

✓Works with Cursor, Claude, LangChain, and any LLM tool

✓Unified billing across all providers

GPT-5.6 Luna Pro API — pricing, context window & access

GPT-5.6 Luna Pro is the same underlying model as GPT-5.6 Luna, served with OpenAI's reasoning mode set to pro. It pairs a 1,050,000-token context window with up to 128,000 output tokens per response, at $0.30 per 1M input and $1.77 per 1M output tokens through YepAPI.

Through YepAPI you call GPT-5.6 Luna Pro on an OpenAI-compatible endpoint with a single key — the same key that reaches GPT-6, Claude, Gemini, Grok and the SEO, SERP and scraping APIs. Input: text, images, files.

What is GPT-5.6 Luna Pro?

GPT-5.6 Luna Pro is the same underlying model as GPT-5.6 Luna, served with OpenAI's reasoning mode set to pro. It deliberates longer before answering, which improves results on complex, multi-step problems at the cost of latency. Per-token pricing matches GPT-5.6 Luna; the added cost is the longer reasoning it chooses to do. It accepts text, images, files as input, handles up to 1,050,000 tokens of context and returns up to 128,000 output tokens per call.

Build with GPT-5.6 Luna Pro via YepAPI

YepAPI serves GPT-5.6 Luna Pro on the OpenAI-compatible /v1/ai/chat endpoint. Point your base URL at YepAPI, add your key, and set the model string to gpt-5.6-luna-pro (or the full openai/gpt-5.6-luna-pro). Function calling, structured outputs and reasoning settings pass straight through, and switching to any other model on the platform is a one-string change per request.

GPT-5.6 Luna Pro API pricing — $0.30 / 1M input, $1.77 / 1M output

GPT-5.6 Luna Pro costs $0.30 per 1M input tokens and $1.77 per 1M output tokens through YepAPI, pay per token with no minimums. Failed calls are never charged, and every request is itemised in your dashboard API Logs so you can see exactly what a 128,000-token response cost.

GPT-5.6 Luna Pro use cases

Use GPT-5.6 Luna Pro for the steps where correctness is worth the wait — final reviews, hard debugging, planning — and plain GPT-5.6 Luna for the rest.

Start generating in 30 seconds

Pay per call, no subscriptions.

Get API Key

What developers say

“Switched from SerpAPI and cut our SERP costs by 80%. Same data quality, way simpler billing.”
Marcus T.
SEO Platform Founder

“One API key for AI models, SERP data, and web scraping. Saved us from managing 4 separate providers.”
Priya S.
Full-Stack Developer

“The $5 free credit let us prototype our entire rank tracking feature before committing. No other API does that.”
Jake R.
Indie Hacker

Frequently asked questions

GPT-5.6 Luna Pro costs $0.30 per 1M input tokens and $1.77 per 1M output tokens through YepAPI, billed per request with no monthly fee. For example, a chat reply (1K input + 500 output tokens) costs about $0.0012.

Sign up at yepapi.com (Google or email, about 30 seconds), open the dashboard and create an API key. The same key works for GPT-5.6 Luna Pro and every other model — no separate OpenAI account or waitlist.

Use "openai/gpt-5.6-luna-pro" as the model on /v1/ai/chat. The short alias "gpt-5.6-luna-pro" also works.

Yes. Point the OpenAI SDK at https://api.yepapi.com/v1/ai with your YepAPI key and set model to "openai/gpt-5.6-luna-pro". Streaming works the same way, so existing OpenAI code only needs the base URL and key changed.

GPT-5.6 Luna Pro supports a 1.1M token context window with up to 128K output tokens per request.