SSyncDev

AI model comparison

Step 3.7 Flash vs Grok 4.20 (Reasoning)

Compare pricing, context limits, supported inputs and deployment options to choose a model for your workflow.

Step 3.7 Flash from StepFun lists 256K context, 256K maximum output, $0.185 input per 1M tokens, $1.11 output per 1M tokens. Grok 4.20 (Reasoning) from xAI lists 1M context, 30K maximum output, $1.25 input per 1M tokens, $2.50 output per 1M tokens. Compare the inputs, outputs and deployment options below to see which fits your workflow.

Side-by-sideCapabilities and practical differences

StepFun

Step 3.7 Flash

Step 3.7 Flash from StepFun: Newer StepFun flash model for faster agents, coding, and multimodal prompts.

Context
256K
Max output
256K
Input / 1M tokens
$0.185
Output / 1M tokens
$1.11

Accepts

  • Text input
  • Image input
  • Video input

Produces

  • Text output
Full model profilegithub.com ↗
VS

xAI

Grok 4.20 (Reasoning)

Grok 4.20 (Reasoning) from xAI: Reasoning Grok for document-heavy analysis and long-horizon tool use.

Context
1M
Max output
30K
Input / 1M tokens
$1.25
Output / 1M tokens
$2.50

Accepts

  • Text input
  • Image input
  • PDF input

Produces

  • Text output
Full model profilegithub.com ↗

At a glance

Key differences

Compare the available figures below, then try both models on the work you need to do.

Step 3.7 Flash

  • Maximum output: 256K
  • Input price: $0.185
  • Output price: $1.11

Grok 4.20 (Reasoning)

  • Context capacity: 1M

Context capacity

Higher listed limit

Step 3.7 Flash:256K

Grok 4.20 (Reasoning):1M

Grok 4.20 (Reasoning)

Maximum output

Higher listed limit

Step 3.7 Flash:256K

Grok 4.20 (Reasoning):30K

Step 3.7 Flash

Input price

Lower listed token rate

Step 3.7 Flash:$0.185

Grok 4.20 (Reasoning):$1.25

Step 3.7 Flash

Output price

Lower listed token rate

Step 3.7 Flash:$1.11

Grok 4.20 (Reasoning):$2.50

Step 3.7 Flash

Specifications

Pricing, limits and capabilities

Specifications for Step 3.7 Flash and Grok 4.20 (Reasoning). Higher limits and lower prices describe these figures only.
SpecificationStep 3.7 FlashGrok 4.20 (Reasoning)
ProviderStepFunxAI
Listed pricing routeStepFunxAI
Model family—grok
Accepted inputstext, image, videotext, image, pdf
Produced outputstexttext
Context window256K1MHigher
Max output256KHigher30K
Input price / 1M$0.185Lower$1.25
Output price / 1M$1.11Lower$2.50
Reasoning modeDocumentedDocumented
Tool callingDocumentedDocumented
Image inputDocumentedDocumented
Audio inputNot documentedNot documented
Structured outputNot documentedDocumented
LicenseOpen weightsProprietary

Workload guidance

Which model should you choose?

Consider Step 3.7 Flash if you need larger maximum output or a lower listed input rate or a lower listed output rate. Consider Grok 4.20 (Reasoning) if you need larger context. Step 3.7 Flash offers downloadable weights; Grok 4.20 (Reasoning) is listed as a proprietary model. Compare licence terms and operating costs before choosing a deployment. Test both on the same representative examples and judge the output against your acceptance criteria. Include tool failures, retries and the time to a completed task.

Documentation and model profiles

Explore each model’s features, API requirements and licence terms in the sources below.

Questions people ask

It brings together documented inputs and outputs, token limits, deployment terms and available pricing. When both models have source-linked, verified results on a shared benchmark, those results are shown with their individual sources. The comparison is a starting point for evaluating your own workload.

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