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xAI · Balanced

Grok 4.20

Added Mar 31, 2026

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Use in the app

SpaceXAI's Grok 4.20 flagship release with tool calling, multimodal input support, and a 2M-token context window. Content policy rejections can still be charged: SpaceXAI may pass through a $0.05 moderation-failure fee, or a $0.055 usage-guidelines violation fee, depending on which rejection upstream returns.

  • Reasoning
  • Tools
  • Vision
  • Structured output
Input
Text, Images
Output
Text
Discovery tier
Balanced

Pricing

USD per 1M tokens
Input
$1.25
Output
$2.50
Cache read
$0.20

Reference prices as published by the model provider. API example

Specifications

Context window
2M
Max output
131.1K
Average output (7 days)
679 tokens
Longer than 60% of 473 models

Side by side

Grok 4.20 compared

Specifications, prices, speed and benchmark scores next to each other. Benchmarks below show every compared model too.

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Grok 4.20xAIThis modelMiMo V2.5 Pro ThinkingxiaomiRemove
ProviderxAIxiaomi
Discovery tierBalancedOpen weights
AddedMar 31, 2026Jun 3, 2026
Limits
Context window2MBest1.05M
Max output131.07K131.07K
Average output679 tokens1.4K tokens
Pricing, USD per 1M tokens
Input$1.25$0.44Best
Output$2.50$0.87Best
Cache read$0.20$0.0036Best
Cache write—$0.00
Performance
Throughput327.6 tok/sBest27.7 tok/s
Time to first token1.8 sBest3.8 s
Request success (24h)99.8%99.9%Best
Benchmark indexes
Intelligence Index25.726.0Best
Coding Index—60.2
Capabilities
ReasoningYesYes
ToolsYesYes
VisionYesNo
Structured outputYesYes
Reasoning effort—none, high

Public evaluations

Benchmarks

Independent evaluation results, with how each score ranks among the models in the Noumen catalog.

  • Grok 4.20
  • MiMo V2.5 Pro Thinking

Intelligence Index

  • Grok 4.2025.7
  • MiMo V2.5 Pro Thinking26.0

Grok 4.20: Better than 62% of 326 scored models

3.8Catalog models by score55.1

Indexes

  • Coding Index

    Composite of the coding evaluations

    • Grok 4.20: —
    • MiMo V2.5 Pro Thinking: 60.2

Agentic work

  • AutomationBench-AA

    Workflow automation, penalized for guardrail violations

    • Grok 4.20: —
    • MiMo V2.5 Pro Thinking: 13.7%

  • AutomationBench-AA tasks completed

    Workflows finished end to end without a guardrail violation

    • Grok 4.20: —
    • MiMo V2.5 Pro Thinking: 2.0%

  • AA-Briefcasev1.1

    Agentic knowledge work, rated head to head

    • Grok 4.20: —
    • MiMo V2.5 Pro Thinking: 883 Elo

  • GDPval-AAv2.1

    Economically valuable occupational tasks, rated head to head

    • Grok 4.20: —
    • MiMo V2.5 Pro Thinking: 1,121 Elo

Document reasoning

  • GDP.pdf

    Professional reasoning over PDF documents, all-pass rate

    • Grok 4.20: —
    • MiMo V2.5 Pro Thinking: 4.0%

  • AA-LCRv1.1

    Reasoning across long documents

    • Grok 4.20: 69.0%
    • MiMo V2.5 Pro Thinking: 79.7%Top

  • MLCR-AA

    Long-context reasoning over medical records

    • Grok 4.20: —
    • MiMo V2.5 Pro Thinking: 5.6%

Reasoning and knowledge

  • Humanity’s Last Exam

    Expert-level questions across academic fields

    • Grok 4.20: 34.5%
    • MiMo V2.5 Pro Thinking: 35.7%Top

  • GPQA Diamond

    Graduate-level science questions

    • Grok 4.20: 91.1%Top
    • MiMo V2.5 Pro Thinking: 86.6%

  • IFBench

    Following precise output instructions

    • Grok 4.20: 81.2%Top
    • MiMo V2.5 Pro Thinking: 79.9%

Coding

  • Terminal-Benchv4.0

    Practical software engineering in a terminal

    • Grok 4.20: —
    • MiMo V2.5 Pro Thinking: 0.0%

  • SciCode

    Scientific computing in Python

    • Grok 4.20: —
    • MiMo V2.5 Pro Thinking: 50.6%

Legacy evaluations

  • Terminal-Bench Hard

    Earlier terminal task suite

    • Grok 4.20: 37.9%
    • MiMo V2.5 Pro Thinking: 43.2%Top

  • τ²-Bench Telecom

    Tool use in a customer-support simulation

    • Grok 4.20: 93.0%
    • MiMo V2.5 Pro Thinking: 94.2%Top

  • AA-LCR (unversioned)

    Long-context reasoning, earlier grading

    • Grok 4.20: 69.0%
    • MiMo V2.5 Pro Thinking: 79.7%Top

Scores from Artificial Analysis, updated Oct 26, 2026. Artificial Analysis

Live routing data

Performance and reliability

Recent averages across requests routed for this model. Your own speed depends on prompt length, reasoning effort and load.

Throughput
327.6 tok/s
Faster than 93% of 260 models
Time to first token
1.8 s
Quicker than 78% of 260 models
Prompt cache hits
58.2%
About $0.64 per 1M input tokens with caching
Request success (24h)
99.8%
Reliable

Cache hits are the share of input tokens recently served from a prompt cache across all requests. They are not a forecast of your own hit rate.

Hourly request success · last 72 hoursLowest hour 75.0%
  • Healthy (98% or more)
  • Degraded (90–98%)
  • Down (under 90%)
  • No requests

Developers

Use it through the API

Noumen’s API is OpenAI-compatible: any Chat Completions client works with a base URL and a key.

Read the quickstart
curl https://www.noumen.xyz/api/v1/chat/completions \
  -H "Authorization: Bearer $NOUMEN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "x-ai/grok-4.20",
    "messages": [{ "role": "user", "content": "Explain this stack trace." }]
  }'
import os
from openai import OpenAI

client = OpenAI(base_url="https://www.noumen.xyz/api/v1", api_key=os.environ["NOUMEN_API_KEY"])
reply = client.chat.completions.create(
    model="x-ai/grok-4.20",
    messages=[{"role": "user", "content": "Explain this stack trace."}],
)
print(reply.choices[0].message.content)

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