Solutions

Cheap GPT-5.6 Luna API

GPT-5.6 Luna is OpenAI's ChatGPT model listed at $1 / $6 per 1M input/output tokens. Through Somnus every top-up is credited at 2× to 2.5×, so you effectively pay $0.5 / $3 or less, on the same OpenAI-compatible key as 50+ other models.

What a top-up buys on GPT-5.6 Luna

You payCredit≈ 1M output tokens of GPT-5.6 Luna
$20 (2×)$406.7
$50 (2.2×)$11018
$100 (2.35×)$23539
$200 (2.5×)$50083

Output-token count only; input tokens are cheaper. First top-up is at least 2.5×.

When to pick GPT-5.6 Luna

GPT-5.6 Luna costs $0.0045 per 1,500-in/500-out request at list price, $0.0022 effective. It sits in the mid price range — a good default for production apps.

GPT-5.6 Luna vs similarly priced models

ModelMakerList (in / out)EffectiveSame request, effective
GLM 5.3Zhipu$1.4 / $4.4$0.7 / $2.2$0.0022
Qwen 3.8 MaxAlibaba$1.65 / $4.95$0.83 / $2.48$0.0025
Claude Haiku 4.5Anthropic$1 / $5$0.5 / $2.5$0.0020
Gemini 3.8 FlashGoogle$0.75 / $3.75$0.38 / $1.88$0.0015

Nearest models to GPT-5.6 Luna by blended price (3 input : 1 output). All run on one Somnus key.

Getting the most out of GPT-5.6 Luna for less

  • Input is 6.0× cheaper than output on GPT-5.6 Luna, so long context with short answers is the cheapest pattern.
  • A $200 top-up gives $500 credit — about 222M blended GPT-5.6 Luna tokens.
  • Mix models: send easy steps to DeepSeek V4 Flash and keep GPT-5.6 Luna for the steps that need it.

Other ChatGPT models on Somnus

ModelList (in / out)Effectivevs GPT-5.6 Luna
GPT-6 Astra$10 / $50$5 / $258.89× the price
GPT-5.6 Sol$5 / $30$2.5 / $155.00× the price

Every OpenAI model shares the same key and balance.

Use GPT-5.6 Luna

javascript
import OpenAI from "openai";

const client = new OpenAI({
  apiKey: process.env.SOMNUS_API_KEY,
  baseURL: "https://gateway-production-c837.up.railway.app/v1",
});

const resp = await client.chat.completions.create({
  model: "claude-sonnet-5",
  messages: [
    {"role": "user", "content": "Summarise this in one line"}
  ],
});
console.log(resp.choices[0].message.content);

Copy the exact model id from your dashboard.

Questions

Is GPT-5.6 Luna really cheaper on Somnus?

Usage is billed at OpenAI's list price, but each dollar you pay is credited as $2–$2.50, so the effective price is half or less.

Do I need a subscription?

No. Top up any amount from $5, or start with the free $5 credit.

Is Somnus affiliated with OpenAI?

No. Somnus is an independent gateway.

Try GPT-5.6 Luna with free credit

$5 free on sign-up, then 2× or more on every top-up.

Create a free account

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