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xAI · Frontier

Grok 4.5

Added Jul 8, 2026

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Use in the app

Grok 4.5 is SpaceXAI's frontier reasoning model for coding, knowledge work, and STEM. It supports text, image, and file inputs with tool calling and structured outputs. Reasoning is always active. 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
Reasoning effort
low · medium · high
Discovery tier
Frontier

Pricing

USD per 1M tokens
Input
$2.00
Output
$6.00
Cache read
$0.30

Reference prices as published by the model provider. API example

Specifications

Context window
500K
Max output
—
Average output (7 days)
1K tokens
Longer than 71% of 473 models

Side by side

Grok 4.5 compared

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

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Grok 4.5xAIThis modelMuse Spark OpenMetaRemove
ProviderxAIMeta
Discovery tierFrontierFrontier
AddedJul 8, 2026Oct 15, 2026
Limits
Context window500K1.05MBest
Average output1K tokens1.3K tokens
Pricing, USD per 1M tokens
Input$2.00$1.25Best
Output$6.00$4.25Best
Cache read$0.30$0.15Best
Performance
Throughput54.2 tok/s—
Time to first token2.5 s—
Request success (24h)100.0%—
Benchmark indexes
Intelligence Index38.838.9Best
Coding Index72.4—
Capabilities
ReasoningYesYes
ToolsYesYes
VisionYesYes
Structured outputYesYes
Reasoning effortlow, medium, highlow, medium, high, xhigh

Public evaluations

Benchmarks

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

  • Grok 4.5
  • Muse Spark Open

Intelligence Index

  • Grok 4.538.8
  • Muse Spark Open38.9

Grok 4.5 tested at high reasoning effort

Grok 4.5: Better than 83% of 326 scored models

3.8Catalog models by score55.1

Indexes

  • Coding Index

    Composite of the coding evaluations

    • Grok 4.5: 72.4
    • Muse Spark Open: —

Agentic work

  • AutomationBench-AA

    Workflow automation, penalized for guardrail violations

    • Grok 4.5: 57.9%Top
    • Muse Spark Open: 49.7%

  • AutomationBench-AA tasks completed

    Workflows finished end to end without a guardrail violation

    • Grok 4.5: 26.3%Top
    • Muse Spark Open: 20.9%

  • AA-Briefcasev1.1

    Agentic knowledge work, rated head to head

    • Grok 4.5: 1,278 Elo
    • Muse Spark Open: 1,279 EloTop

  • GDPval-AAv2.1

    Economically valuable occupational tasks, rated head to head

    • Grok 4.5: 1,381 Elo
    • Muse Spark Open: 1,401 EloTop

Document reasoning

  • GDP.pdf

    Professional reasoning over PDF documents, all-pass rate

    • Grok 4.5: 18.8%Top
    • Muse Spark Open: 18.6%

  • AA-LCRv1.1

    Reasoning across long documents

    • Grok 4.5: 79.3%Top
    • Muse Spark Open: 78.3%

  • MLCR-AA

    Long-context reasoning over medical records

    • Grok 4.5: 16.1%Top
    • Muse Spark Open: 7.8%

Reasoning and knowledge

  • Humanity’s Last Exam

    Expert-level questions across academic fields

    • Grok 4.5: 42.7%
    • Muse Spark Open: 43.9%Top

  • GPQA Diamond

    Graduate-level science questions

    • Grok 4.5: 93.1%Top
    • Muse Spark Open: 89.0%

Coding

  • Terminal-Benchv4.0

    Practical software engineering in a terminal

    • Grok 4.5: 10.6%Top
    • Muse Spark Open: 8.1%

  • SciCode

    Scientific computing in Python

    • Grok 4.5: 55.0%
    • Muse Spark Open: 58.4%Top

Legacy evaluations

  • AA-LCR (unversioned)

    Long-context reasoning, earlier grading

    • Grok 4.5: 79.3%Top
    • Muse Spark Open: 78.3%

Scores from Artificial Analysis, updated Oct 26, 2026. Grok 4.5 was tested at high reasoning effort; compare scores measured at the same effort.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
54.2 tok/s
Faster than 38% of 260 models
Time to first token
2.5 s
Quicker than 66% of 260 models
Prompt cache hits
64.6%
About $0.90 per 1M input tokens with caching
Request success (24h)
100.0%
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 66.6%
  • 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-4.5",
    "reasoning_effort": "medium",
    "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-4.5",
    messages=[{"role": "user", "content": "Explain this stack trace."}],
)
print(reply.choices[0].message.content)

xAI

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