Model detail
GPT-6 Luna
GPT-6 Luna is the fast, cost-efficient model in OpenAI's GPT-6 series, positioned below GPT-6 Sol. It is suited for high-volume and latency-sensitive workloads such as chat, classification, and lightweight agentic tasks, and at higher reasoning effort it can take on complex software engineering and computer-use tasks that previously called for a Sol-tier model. It shares the GPT-6 family's gains in factual reliability and its clearer, more concise communication style.
Model specs
- Model ID
-
gpt-6-luna
- Context length
- 1.05M
- Max output
- 128K
- I/O modalities
- Released
- 2026-09
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API endpoints
One MixRoute gateway, OpenAI-compatible
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OpenAI-compatible
/v1/chat/completionsPOST
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Tiered pricing
Unit: /1M Tokens
| Tier | Input /1M Tokens | Output /1M Tokens | Cache read /1M Tokens | Cache write /1M Tokens |
|---|---|---|---|---|
| standard Length ≤ 272K | $0.1000 | $0.5000 | $0.0100 | $0.1250 |
| long_context Length > 272K | $0.2000 | $0.7500 | $0.0200 | $0.2500 |
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Selection summary
Quickly judge whether it fits your workload
What is this model good for?
GPT-6 Luna is the fast, cost-efficient model in OpenAI's GPT-6 series
GPT-6 Luna is the fast, cost-efficient model in OpenAI's GPT-6 series, positioned below GPT-6 Sol.
What should you check before using it?
1,050,000 context, 128,000 output tokens
gpt-6-luna supports reasoning, tool calling, structured output, streaming, prompt caching, vision input and the OpenAI SDK. Knowledge cutoff: 2026-05-18. Released 2026-09-22.
Why use it through MixRoute?
gpt-6-luna cache reads cut repeated-prompt cost
Cached prefixes are billed at $0.0100 per 1M tokens for inputs up to 272,000 tokens (standard input $0.1000); above that, $0.0200 and $0.2000 respectively, so repeated system prompts cost less. MixRoute serves gpt-6-luna on the OpenAI-compatible endpoint /v1/chat/completions; point your existing client at https://api.mixroute.ai/v1 with the model ID gpt-6-luna and re-run your integration tests.
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Capabilities & compatibility
Unconfirmed capabilities stay "Unknown," no guesses
Tool calling
gpt-6-luna supports function and tool calls.
tools definition; the response returns tool_calls to execute and feed results back.
Structured output
gpt-6-luna can produce JSON-formatted output on demand.
response_format: { type: "json_schema" } forces valid JSON output.
Streaming
gpt-6-luna supports streamed responses.
stream: true streams tokens incrementally, so chat UIs render as they arrive.
Prompt caching
gpt-6-luna supports prompt caching under supported routing conditions.
Vision input
gpt-6-luna can process image inputs alongside text.
image_url content part alongside text messages.
OpenAI SDK
Call gpt-6-luna through MixRoute's OpenAI-compatible endpoint.
base_url to https://api.mixroute.ai/v1; everything else follows the OpenAI style.
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Token cost estimator
Live estimate from this page's pricing, not an actual bill
Share of the same prefix read repeatedly, up to 100%
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FAQ
Yes. gpt-6-luna is reachable through an OpenAI-compatible endpoint, so an existing OpenAI SDK client works after pointing the base URL at MixRoute and setting the model parameter to gpt-6-luna. Keep your current request and response handling.
One endpoint, a testable decision
Test this model and alternate routes with the same request format
Start from a real workload, then let quality, total cost, and failure conditions decide whether to send production traffic.