Grok 4.20 Reasoning

Text & chatUnavailable

by xAIgrok-4-20-reasoning

xAI's Grok 4.20 reasoning snapshot. Runs an extended thinking pass before answering for multi-step analysis, math and STEM, with a 1M token context window and strong agentic tool calling.

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Status: Unavailable
Context: 1,000,000 tokens
Max. output: 16,384 tokens
Input → output: Text → Text
Developer: xAI
Updated: September 23, 2026

Grok 4.20 Reasoning is currently unavailable

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Playground

Try Grok 4.20 Reasoning

Input & output

Currently unavailable

Currently unavailable.

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Prompt

0 / 16,000

User message

Advanced settings (3)

System prompt(optional)

0 / 8,000

Optional system instruction

Max. tokens(optional)1–16,384

Temperature(optional)0–2

⌘/Ctrl + Enter

Output

The answer appears here.

This run

No price – currently unavailable.

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About Grok 4.20 Reasoning

TL;DRAs of September 23, 2026

Grok 4.20 Reasoning is a model by xAI in the Text & chat category. Grok 4.20 Reasoning is currently not available on Railwail. The context window holds 1,000,000 tokens, and one response can be up to 16,384 tokens long.

Pricing

Currently unavailable. There is no price for this model at the moment, so it cannot be run.

API

Call Grok 4.20 Reasoning with your Railwail API key. Use this model ID in the request:

grok-4-20-reasoningAPI documentation Get an API key

No verified API example

The public API passes a different input format than this model needs. Use the playground above.

Specifications

Model ID: grok-4-20-reasoning
Developer: xAI
Category: Text & chat
Input: Text
Output: Text
Context window: 1,000,000 tokens
Max. output: 16,384 tokens
Catalog entry updated: September 23, 2026

Input parameters

Inputs and settings from the model's input schema. The example in the API section shows which of them the API accepts.

ParameterTypeDefaultAllowed values

promptrequired
User message
Type: Text
Default: –
Allowed values: up to 16,000 characters
max_tokens
Type: Integer
Default: 2048
Allowed values: 1 to 16,384
temperature
Type: Number
Default: 0.7
Allowed values: 0 to 2
system_prompt
Optional system instruction
Type: Text
Default: –
Allowed values: up to 8,000 characters

Use cases

Related guides

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Frequently asked questions

What is Grok 4.20 Reasoning?

Grok 4.20 Reasoning is a model by xAI in the Text & chat category. It is listed on Railwail but cannot be run at the moment.

How much does Grok 4.20 Reasoning cost on Railwail?

Grok 4.20 Reasoning cannot be run on Railwail at the moment, so there is no current price. Available alternatives with prices are listed further down this page.

What is the context window of Grok 4.20 Reasoning?

The context window of Grok 4.20 Reasoning holds 1,000,000 tokens. One response can be up to 16,384 tokens long.

How fast is Grok 4.20 Reasoning?

There are not enough measured runs of Grok 4.20 Reasoning on Railwail yet to state a run time. It depends on the input, the settings and the load at the provider.

Is Grok 4.20 Reasoning better than Claude Fable 5.1?

That depends on the task. Grok 4.20 Reasoning (xAI) and Claude Fable 5.1 (Anthropic) are both models in the Text & chat category. The comparison page shows their prices and specifications side by side.

Compare Grok 4.20 Reasoning and Claude Fable 5.1

Can I use Grok 4.20 Reasoning right now?

Currently unavailable. The page stays online; available alternatives from the same category are listed further down.

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One API key for every model on Railwail. Usage is charged from prepaid credits, 1 credit = $0.01.

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