xAI · Balanced
Grok 4.20
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
Compare models
Put Grok 4.20 next to up to three other models. The comparison stays in the link, so you can share it.
Public evaluations
Benchmarks
Independent evaluation results, with how each score ranks among the models in the Noumen catalog.
Intelligence Index
25.7
Better than 62% of 326 scored models
Document reasoning
AA-LCRv1.1
69.0%Reasoning across long documents
Better than 45% of 309 scored models
Reasoning and knowledge
Humanity’s Last Exam
34.5%Expert-level questions across academic fields
Better than 68% of 323 scored models
GPQA Diamond
91.1%Graduate-level science questions
Better than 81% of 291 scored models
IFBench
81.2%Following precise output instructions
Better than 97% of 215 scored models
Legacy evaluations
Terminal-Bench Hard
37.9%Earlier terminal task suite
Better than 74% of 212 scored models
τ²-Bench Telecom
93.0%Tool use in a customer-support simulation
Better than 80% of 214 scored models
AA-LCR (unversioned)
69.0%Long-context reasoning, earlier grading
Better than 45% of 309 scored models
Scores from Artificial Analysis, updated Oct 26, 2026. Artificial Analysis
- #7Vision Style Control · Entity Recognition1238.1
Ranks among Noumen catalog models on LMArena leaderboards. Only top-20 placements are listed.LMArena
- #14FrontierMath v2 (Tiers 1–3)44.9%
- #12GPQA Diamond89.3%
Ranks among Noumen catalog models on Epoch AI leaderboards. Only top-20 placements are listed.Epoch AI
- #20ARC-AGI-3 (Default harness)0.1%
Ranks among Noumen catalog models on ARC Prize leaderboards. Only top-20 placements are listed.ARC Prize
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
- 100.6 tok/s
- Faster than 62% of 257 models
- Time to first token
- 2.2 s
- Quicker than 69% of 257 models
- Prompt cache hits
- 27.8%
- About $0.96 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.
- 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.
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)xAI
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