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GPT-5.6 Luna
openaiopenai/gpt-5.6-luna
OpenAI's GPT-5.6 family (Luna tier). The cost/efficiency entry point into the 5.6 generation.
GPT-5.6 Luna is the cost/efficiency entry point of OpenAI's GPT-5.6 family, verified live 2026-07-27 on the OpenAI direct API, Azure OpenAI eastus2 (deployed by the operator the same day), and OpenRouter.
Best for
- • High-volume, cost-sensitive chat and classification workloads
Reach for something else if
- • Frontier reasoning or long-horizon agent tasks — route to gpt-5.6-sol instead
Context Length
1M
Max Output
128K
Input Priceper 1M tokens
$0.216/ 1M tokens
Output Priceper 1M tokens
$1.30/ 1M tokens
Modalities
textimage→text
Capabilities
Vision
Pricing Breakdown
| Type | Rate |
|---|---|
| Prompts up to 272K tokens | |
| Input | $0.216 / 1M tokens |
| Output | $1.30 / 1M tokens |
| Cached input | $0.0216 / 1M tokens |
| Cache write (5m) | $0.270 / 1M tokens |
| Prompts over 272K tokens | |
| Input | $0.432 / 1M tokens |
| Output | $1.94 / 1M tokens |
| Cached input | $0.0432 / 1M tokens |
| Cache write | $0.540 / 1M tokens |
Tiered pricing: when a request's prompt (input, cached tokens included) is over 272K tokens, every token in that request is billed at the long-context rates; exactly 272K is still the base rate.
Supported Parameters
temperaturemax_tokenstop_ptoolstool_choiceresponse_formatreasoningstop
Specifications
| Release date | Not publicly disclosed | unknown |
| License | Commercial via OpenAI API / Azure OpenAI | verified |
Benchmarks
| Benchmark | Distribution | Score | Source |
|---|---|---|---|
Not publicly disclosed | — | Not publicly disclosed | — |
API Usage Examples
Use the global api.therouter.ai endpoint shown below for new integrations; the legacy China accelerated endpoint is retired.
cURL
curl https://api.therouter.ai/v1/chat/completions -H "Content-Type: application/json" -H "Authorization: Bearer $THE_ROUTER_API_KEY" -d '{
"model": "openai/gpt-5.6-luna",
"messages": [
{"role": "user", "content": "Summarize the key points from this input."}
]
}'API guide
Chat completion
cURL
curl https://api.therouter.ai/v1/chat/completions \
-H "Authorization: Bearer $THEROUTER_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model":"openai/gpt-5.6-luna","messages":[{"role":"user","content":"Hello"}]}'More from openai
Guides
Fact ledger — every claim on this page traces here
| source | URL | retrieved | |
|---|---|---|---|
| Release date | — | — | unknown |
| License | — | — | verified |
| Not publicly disclosed | openai.com ↗ | 2026-07-27 | unknown |