AI model comparison

Step 5 Preview vs Muse Spark 1.3

Pricing, context window, benchmarks, and features compared side by side. Or skip the guesswork and send one prompt to both.

Step 5 Preview is StepFun's flagship model for agentic work, built on a sparse Mixture-of-Experts architecture (27B active / 600B total parameters).

Input / 1M
$1
Output / 1M
$2.70
Context
1.05M

Muse Spark 1.3 is a multimodal reasoning model from Meta for long-running agentic, multi-agent, and coding workflows.

Input / 1M
$1.25
Output / 1M
$4.25
Context
1.05M

At a glance

Quick verdict

How the two models stack up on the things people ask about most.

Lower price

stepfun logo

Step 5 Preview

1.4x cheaper for a typical chat

Higher intelligence score

meta logo

Muse Spark 1.3

48.1 vs 43.7 on Artificial Analysis

Larger context window

Tie

1.05M vs 1.05M tokens

Newer release

stepfun logo

Step 5 Preview

Released October 8, 2026

Benchmarks

Benchmark scores

Independent scores from Artificial Analysis. Higher is better.

Intelligence index

stepfun logoStep 5 Preview43.7
meta logoMuse Spark 1.348.1

Coding index

stepfun logoStep 5 PreviewNot available
meta logoMuse Spark 1.375.8

Agentic index

stepfun logoStep 5 PreviewNot available
meta logoMuse Spark 1.355.5

Pricing

Step 5 Preview vs Muse Spark 1.3 API pricing

Per-token API rates. Cheaper option highlighted.

Metricstepfun logoStep 5 Previewmeta logoMuse Spark 1.3
Input tokensPer 1M tokens$1$1.25
Output tokensPer 1M tokens$2.70$4.25
Cached input (read)Per 1M tokens$0.05$0.15
Cache writePer 1M tokensNot availableNot available
Web searchPer requestNot available$0.0025

What it costs in practice

Estimated cost per 1,000 requests at standard rates. Coding and long-document figures also show the cost when the input is already cached.

Chat message

2K in, 500 out

stepfun logoStep 5 Preview$3.35
meta logoMuse Spark 1.3$4.63

Coding task

30K in, 4K out

stepfun logoStep 5 Preview$40.80$12.30 cached
meta logoMuse Spark 1.3$54.50$21.50 cached

Long document summary

150K in, 2K out

stepfun logoStep 5 Preview$155.40$12.90 cached
meta logoMuse Spark 1.3$196$31 cached

Specs

Context window and capabilities

How much each model can read, how much it can write, and what it accepts as input.

Metricstepfun logoStep 5 Previewmeta logoMuse Spark 1.3
Context window1.05M tokens1.05M tokens
Max output64K tokens944K tokens
Input typesImage, Text, VideoFile, Image, Text, Video
Output typesTextText
Reasoning effort levelsHigh, Medium, LowMax, Extra high, High, Medium, Low, Minimal
Default reasoning effortMediumMedium
Release dateOctober 8, 2026September 2, 2026

Features

Supported features

API features available for each model.

Metricstepfun logoStep 5 Previewmeta logoMuse Spark 1.3
Tool callingSupportedSupported
Structured outputsSupportedSupported
JSON modeSupportedSupported
ReasoningSupportedSupported
TemperatureSupportedSupported
Stop sequencesSupportedNot supported
Deterministic seedSupportedNot supported
Verbosity controlNot supportedNot supported

Our take

Step 5 Preview is 1.4x cheaper for a typical chat. Muse Spark 1.3 scores higher on the Artificial Analysis Intelligence Index (48.1 vs 43.7). The right pick depends on your workload, so the quickest way to settle it is to send the same prompt to both and compare.

FAQ

Frequently asked questions

Is Step 5 Preview or Muse Spark 1.3 cheaper?

Step 5 Preview is cheaper for a typical chat (2K input tokens and 500 output tokens). Step 5 Preview costs $1 per 1M input tokens and $2.70 per 1M output tokens, while Muse Spark 1.3 costs $1.25 per 1M input tokens and $4.25 per 1M output tokens.

Which has a bigger context window, Step 5 Preview or Muse Spark 1.3?

Step 5 Preview supports up to 1.05M tokens of context, compared with 1.05M for Muse Spark 1.3.

Is Step 5 Preview smarter than Muse Spark 1.3?

On the Artificial Analysis Intelligence Index, Step 5 Preview scores 43.7 and Muse Spark 1.3 scores 48.1, putting Muse Spark 1.3 ahead. Benchmarks don't capture everything, so the best test is running your own prompts through both.

Can I use Step 5 Preview and Muse Spark 1.3 at the same time?

Yes. Shortcut Chat sends one prompt to multiple models at once, so you can see Step 5 Preview and Muse Spark 1.3 answer side by side and keep the better response.

stepfun logometa logo

Why choose? Ask both.

Send one prompt to Step 5 Preview and Muse Spark 1.3 at the same time. Compare the answers side by side and keep the best one.