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Model detail

GPT-6 Luna

Provided by OpenAI
Pay-as-you-go Dynamic pricing 2 tiers

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

02

API endpoints

One MixRoute gateway, OpenAI-compatible

  • OpenAI-compatible /v1/chat/completions POST

03

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

05

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.

07

Capabilities & compatibility

Unconfirmed capabilities stay "Unknown," no guesses

Available:

Tool calling

gpt-6-luna supports function and tool calls.

EX Send a tools definition; the response returns tool_calls to execute and feed results back.
Available:

Structured output

gpt-6-luna can produce JSON-formatted output on demand.

EX response_format: { type: "json_schema" } forces valid JSON output.
Available:

Streaming

gpt-6-luna supports streamed responses.

EX stream: true streams tokens incrementally, so chat UIs render as they arrive.
Available:

Prompt caching

gpt-6-luna supports prompt caching under supported routing conditions.

EX Keep the system prompt and tool definitions at the start of the request; repeated prefixes are automatically billed at the cache-read rate.
Available:

Vision input

gpt-6-luna can process image inputs alongside text.

EX Pass a base64-encoded image in a image_url content part alongside text messages.
Available:

OpenAI SDK

Call gpt-6-luna through MixRoute's OpenAI-compatible endpoint.

EX Change base_url to https://api.mixroute.ai/v1; everything else follows the OpenAI style.

08

Token cost estimator

Live estimate from this page's pricing, not an actual bill

Share of the same prefix read repeatedly, up to 100%

09

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.