Muse Spark 1.3

Muse Spark 1.3 is the recommended model on the Meta Model API, a developer platform Meta runs as a public preview. The Muse Spark line comes from Meta Superintelligence Labs, and version 1.3, released September 2, 2026, targets long-horizon coding and agentic work with a 1,048,576-token context window.

By MetaReleased September 2, 2026Data checked October 10, 2026

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Specifications

Context window: 1Mabout 786,000 words, or 1,570 pages
Max output: Not published
Input price: $1.25per 1M tokens
Output price: $4.25per 1M tokens
Cached input: $0.15per 1M tokens
Weights: ClosedProprietary
Parameters: Undisclosed
Input types: Text, Images, Video, PDF
Output types: Text
Reasoning mode: Yes
Tool calling: Yes
Released: Sep 2, 2026Preview

Standard tier; no long-context premium. A contributor tier (muse-spark-1.3-contributor) costs $0.10 input, $0.002 cached and $0.20 output in exchange for letting Meta train on prompts and completions. Max output is not documented.

What it costs in practice

Workload	Monthly cost at list price
Support chatbot30,000 conversations a month, 2,000 input and 400 output tokens each	$126
Document summaries2,000 documents a month, 12,000 input and 800 output tokens each	$37
Coding agent1,000 tasks a month, 60,000 input and 6,000 output tokens each	$100

Standard rates, no caching or batch discounts. Run your own numbers.

Strengths

$1.25 input and $4.25 output per million tokens, with no long-context premium
Accepts text, image, video and PDF input
Adjustable reasoning effort, including a max level on the standard tier

Trade-offs to weigh

The Meta Model API is still in public preview
Meta says audio input is not fully supported on 1.3 and recommends Muse Spark 1.2 for audio

Where it fits

Meta positions Muse Spark 1.3 for:

codingagentsmultimodallong documents

Where you can use it

API
OpenRouter
Muse Code

Alternatives to consider

Model	Tier	Context	Input / output per 1M
Gemini 3.8 FlashGoogle	Advanced	1M	$0.75 / $3.75	Compare
Gemini 3.6 FlashGoogle	Advanced	1M	$0.75 / $3.75	Compare
Claude Sonnet 5.5Anthropic	Advanced	1M	$2 / $10	Compare
GPT-6.1 SolOpenAI	Advanced	1.05M	$2 / $10	Compare

Frequently asked questions

How much does Muse Spark 1.3 cost?

Muse Spark 1.3 lists at $1.25 per million input tokens and $4.25 per million output tokens, with cached input at $0.15 (checked October 10, 2026). Standard tier; no long-context premium. A contributor tier (muse-spark-1.3-contributor) costs $0.10 input, $0.002 cached and $0.20 output in exchange for letting Meta train on prompts and completions. Max output is not documented. Confirm current rates on the provider's pricing page before you commit.

What is the context window of Muse Spark 1.3?

Muse Spark 1.3 accepts up to 1,048,576 tokens of context (about 786,000 words, or 1,570 pages). Long prompts cost more and can be slower, so most apps send only what the task needs.

Is Muse Spark 1.3 open source?

No. Muse Spark 1.3 is a proprietary model from Meta; its weights aren't published. You can use it through the Meta API and through OpenRouter, Muse Code.

What is Muse Spark 1.3 best for?

Meta positions Muse Spark 1.3 for coding, agents, multimodal, long documents. It accepts text, images, video, pdf as input, has a reasoning (thinking) mode and supports tool calling. Test it on a sample of your own tasks before you choose it for production.

Sources

Facts checked against these pages on October 10, 2026. Spot an error? Tell us.

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