Same API, One-Line Escalation
Luna runs on the same endpoint and schema as Sol and Terra. Route bulk traffic through gpt-5.6-luna, then escalate hard requests to a stronger tier by changing one model string.
GPT 5.6 Luna
gpt-5.6-luna is the fastest and cheapest tier of OpenAI's GPT-5.6 family, built for cost-sensitive, high-volume workloads: classification, extraction, summarization, and user-facing chat. The gpt 5.6 luna api on GPTProto costs $0.80/$4.80 per 1M tokens — 20% under OpenAI's $1/$6 list price.
API Usage Examples
curl --request POST "https://gptproto.com/v1/chat/completions" \
--header "Authorization: Bearer $GPTPROTO_API_KEY" \
--header "Content-Type: application/json" \
--data '{
"model": "gpt-5.6-luna",
"messages": [
{
"role": "user",
"content": "Hello"
}
]
}'GPT 5.6 Luna pricing
Chat, coding agents & document work. Priced per 1M tokens — input, cached input and output are billed separately. GPTProto is 20% below official rates.
Your usage
OpenAI · ≈ 148M tokens/mo (48M cached)
OpenRouter
List + 5.5% credit fee
$33.08
per month
Input (non-cached)$6.752
Cache read$1.0128
Output$25.32
OpenAI
Direct from OpenAI (list price)
$31.36
per month
Input (non-cached)$6.4
Cache read$0.96
Output$24
BEST VALUE
GPTProto
20% off official
$25.09
per month
After discount$25.09
Effective$25.09
Monthly cost by source
OpenRouter
$33.08
OpenAI
$31.36
GPTProto
$25.09
Save $6.27 / month
on GPTProto vs OpenAI (−20%)
Annual savings ≈ $75.26 · pay as you go
OpenRouter costs include its ~5.5% credit purchase fee. GPTProto applies a per-model discount (10–30% off) and your bonus credits are also spent at discounted rates — savings compound. Estimates assume a 60% cache hit rate.
Related Models
All Models
| Model | Input → Output | ||||
|---|---|---|---|---|---|
| 1.05M | $0.16 / $0.96 per 1M | $0.20 / $0.02 per 1M | Input: TextInput: ImageInput: Document Output: Text | |
| — | — | $0.30 / $1.20 per 1M | — / $0.006 per 1M | Input: TextInput: Image Output: Text | |
| 1.05M | $0.79 / $2.38 per 1M | — / $0.04 per 1M | Input: Text Output: Text | ||
| 1.05M | $8.00 / $40.00 per 1M | $10.00 / $0.80 per 1M | Input: TextInput: ImageInput: Document Output: Text | ||
| 1.05M | $0.90 / $4.50 per 1M | $0.60 / $0.09 per 1M | Input: TextInput: ImageInput: VideoInput: DocumentInput: Audio Output: Text | ||
| 1M | $9.00 / $45.00 per 1M | $11.25 / $0.23 per 1M | Input: TextInput: ImageInput: Document Output: Text | ||
| 1M | $1.80 / $5.40 per 1M | $2.25 / $0.23 per 1M | Input: TextInput: ImageInput: VideoInput: DocumentInput: Audio Output: Text | ||
| — | 1.31M | $0.15 / $0.50 per 1M | — / $0.03 per 1M | Input: TextInput: ImageInput: VideoInput: Document Output: Text | |
| — | 1.05M | $0.30 / $1.20 per 1M | — / $0.006 per 1M | Input: TextInput: Image Output: Text | |
| 1.31M | $1.26 / $3.96 per 1M | — / $0.23 per 1M | Input: TextInput: ImageInput: Document Output: Text | ||
| 1.05M | $0.90 / $4.50 per 1M | $0.60 / $0.09 per 1M | Input: TextInput: ImageInput: Document Output: Text | ||
| 500K | $1.20 / $3.60 per 1M | — / $0.30 per 1M | Input: TextInput: Image Output: Text | ||
| 1M | $1.80 / $5.40 per 1M | $2.25 / $0.23 per 1M | Input: TextInput: ImageInput: VideoInput: Document Output: Text | ||
| 1M | $4.50 / $22.50 per 1M | $5.63 / $0.45 per 1M | Input: TextInput: ImageInput: Document Output: Text | ||
| 1.05M | $0.90 / $4.50 per 1M | $0.60 / $0.09 per 1M | Input: TextInput: ImageInput: Document Output: Text | ||
| 1.05M | $2.70 / $13.50 per 1M | $0.27 / $0.27 per 1M | Input: TextInput: ImageInput: Document Output: Text | ||
| 1.05M | $1.60 / $9.60 per 1M | $2.00 / $0.16 per 1M | Input: TextInput: ImageInput: Document Output: Text | ||
| 1.05M | $3.20 / $16.00 per 1M | $4.00 / $0.32 per 1M | Input: TextInput: ImageInput: Document Output: Text | ||
| 500K | $1.20 / $3.60 per 1M | $0.30 / $0.30 per 1M | Input: TextInput: Image Output: Text | ||
| 1M | $1.80 / $9.00 per 1M | $2.25 / $0.18 per 1M | Input: TextInput: Document Output: Text | ||
| 1.05M | $0.48 / $0.96 per 1M | $0.10 / $0.10 per 1M | Input: TextInput: ImageInput: Document Output: Text | ||
| 1.05M | $1.26 / $3.96 per 1M | $0.23 / $0.23 per 1M | Input: TextInput: ImageInput: Document Output: Text | ||
| — | $1.00 / $8.00 per 1M | $0.10 / $0.10 per 1M | Input: TextInput: ImageInput: Document Output: Text | ||
| 1M | $0.36 / $1.44 per 1M | $0.07 / $0.07 per 1M | Input: TextInput: Document Output: Text | ||
| — | 1.05M | $0.30 / $1.20 per 1M | — / $0.006 per 1M | Input: Text Output: Text | |
| 1M | $0.75 / $1.50 per 1M | $0.12 / $0.12 per 1M | Input: TextInput: Image Output: Text | ||
| 1.05M | $24.00 / $144.00 per 1M | — | Input: TextInput: ImageInput: Document Output: Text | ||
| 1.05M | $24.00 / $144.00 per 1M | — | Input: TextInput: ImageInput: Document Output: Text | ||
| 262K | $0.85 / $3.60 per 1M | $0.14 / $0.14 per 1M | Input: TextInput: Document Output: Text | ||
| 205K | $0.24 / $0.96 per 1M | $0.30 / $0.02 per 1M | Input: TextInput: Document Output: Text | ||
| 262K | $0.54 / $2.70 per 1M | $0.09 / $0.09 per 1M | Input: TextInput: Document Output: Text | ||
| 262K | $0.10 / $0.97 per 1M | — | Input: TextInput: Image Output: Text | ||
| 262K | $0.10 / $0.97 per 1M | — | Input: TextInput: Image Output: Text | ||
| 262K | $0.02 / $0.18 per 1M | — | Input: TextInput: Image Output: Text |
GPT 5.6 Luna API
The fastest, lowest-cost tier of OpenAI's GPT-5.6 family — built for classification, extraction, and chat at volume.
Lowest Cost in the GPT-5.6 Family
At $0.80/$4.80 per 1M tokens on GPTProto, gpt-5.6-luna is the cheapest way to run GPT-5.6 — one-fifth of Sol's rate. The 20% discount under OpenAI's list compounds fast at volume.
Strong for Its Price Class
gpt-5.6-luna corresponds to the nano tier of earlier GPT-5 generations, yet scores 84.7% on Terminal-Bench 2.1 and 62.7% on SWE-Bench Pro in OpenAI's published results — unusual capability at this price.
1M-Token Context Window
Luna shares the family's 1,050,000-token context and 128K output cap. OpenAI's own testing shows retrieval weakens at extreme depths on this tier — keep critical facts early in long prompts.
What Is GPT 5.6 Luna?
GPT 5.6 Luna is the smallest tier of OpenAI's GPT-5.6 family, released to general availability on July 9, 2026 alongside gpt-5.6-sol and gpt-5.6-terra. OpenAI designed it for cost-sensitive, high-volume workloads — the tier that roughly replaces the nano models of earlier GPT-5 generations. If you're asking what is gpt 5.6 luna api access good for, the short answer: any job where you process a lot of tokens and the task is easy to verify — classification, tagging, extraction, summarization, and first-line chat.
The openai gpt 5.6 luna api is available on GPTProto with the same model string and OpenAI-compatible schema, billed from one balance that also covers Sol, Terra, and 200+ other models.
| Spec | gpt-5.6-luna |
|---|---|
| Provider | OpenAI |
| Modality | Text & Image in / text out |
| Context window | 1,050,000 tokens |
| Max output | 128,000 tokens |
| Knowledge cutoff | February 16, 2026 |
| Reasoning effort | none / low / medium / high / xhigh / max |
| Structured outputs | Strict JSON schema mode |
| GPTProto price | $0.80 input / $4.80 output per 1M tokens |
| Official price | $1 input / $6 output per 1M tokens |
| Model string | gpt-5.6-luna |
What high-volume work costs on GPTProto ($0.80/$4.80 per 1M):
| Workload | Input | Output | GPTProto cost | Official cost |
|---|---|---|---|---|
| 1,000 document summaries | 2M | 300K | $3.04 | $3.80 |
| Classification batch | 10M | 500K | $10.40 | $13.00 |
| Chatbot, monthly | 50M | 10M | $88.00 | $110.00 |
Difference Between GPT 5.6 Luna and Sol
Luna and Sol are the two ends of the gpt 5.6 luna model family's cost-capability curve. The published numbers:
| gpt-5.6-luna | gpt-5.6-sol | |
|---|---|---|
| Tier | Fastest, cheapest (nano-equivalent) | Flagship |
| Terminal-Bench 2.1 | 84.7% | 88.8% (91.9% with ultra) |
| SWE-Bench Pro | 62.7% | 64.6% |
| Artificial Analysis Intelligence Index | 51 | 59 |
| Artificial Analysis Coding Agent Index | 74.6 | 80 |
| Long-context behavior | Degrades more sharply at depth (OpenAI testing) | Strongest retrieval of the family |
| ultra multi-agent mode | No | Yes |
| Official price per 1M | $1 / $6 | $5 / $30 |
| GPTProto price per 1M | $0.80 / $4.80 | $4 / $24 |
Honest read: Sol is roughly 4–8 points better across benchmarks at five times the price. That trade is worth it for long agent runs and tasks that are expensive to redo; it is rarely worth it for bulk classification or summarization. A common production pattern is routing: default to cheaper gpt 5.6 luna api calls, escalate to Sol when a request fails validation or exceeds a complexity threshold. For the middle option, see gpt-5.6-terra; the full three-tier table lives on the Sol page.
gpt 5.6 luma Common Questions
Find technical answers and integration tips for the gpt 5.6 luma creative model to help you build more empathetic applications.
How do I migrate to the gpt-5.6-luna api?
A: The API is OpenAI-compatible: point your base_url at GPTProto, use your GPTProto key, and set the model string to gpt-5.6-luna. Prompts, JSON schemas, and tool definitions carry over unchanged from any OpenAI-style client.
Does gpt 5.6 luna support multimodal inputs?
Yes, it natively supports image, audio, and video inputs. It is particularly strong at visual UI reasoning, meaning it can take a hand-drawn wireframe or a UI screenshot and help convert it into functional code like Tailwind or React. This makes it an invaluable tool for developers looking to bridge the gap between design mockups and front-end implementation.
What is the difference between gpt 5.6 luna and sol?
Luna is the cheapest, fastest tier ($0.80/$4.80 per 1M on GPTProto); Sol is the flagship ($4/$24). Sol leads benchmarks by 4–8 points; Luna wins on cost per task. See the comparison table above.
How is the gpt 5.6 luna api priced?
$0.80 per 1M input tokens and $4.80 per 1M output tokens — 20% off gpt 5.6 luna api access compared with OpenAI's $1/$6 list price. No platform fee; billing comes from a balance shared across 200+ models.
Is my data used to train the gpt 5.6 luma model?
No. All requests sent through GPTProto.com are protected by enterprise-grade data privacy agreements. Your data is excluded from OpenAI's training sets by default. This ensures that your proprietary creative work, unique brand instructions, and sensitive user interactions remain confidential and are never used to improve public model weights.
Is the gpt 5.6 luna api open source?
No — GPT-5.6 Luna is a proprietary OpenAI model with no open weights. GPTProto provides API access without an OpenAI account, which is what most "open source" searches for this model are actually after: fewer sign-up hurdles, not weights.
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