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
Grok 4.20 compared
Specifications, prices, speed and benchmark scores next to each other. Benchmarks below show every compared model too.
| Grok 4.20xAIThis model | Grok Build 0.1xAIRemove | |
|---|---|---|
| Provider | xAI | xAI |
| Discovery tier | Balanced | Balanced |
| Added | Mar 31, 2026 | May 20, 2026 |
| Limits | ||
| Context window | 2MBest | 256K |
| Max output | 131.07K | — |
| Average output | 679 tokens | 3K tokens |
| Pricing, USD per 1M tokens | ||
| Input | $1.25 | $1.00Best |
| Output | $2.50 | $2.00Best |
| Cache read | $0.20 | $0.20 |
| Performance | ||
| Throughput | 108.7 tok/s | — |
| Time to first token | 2.5 s | — |
| Request success (24h) | 99.8% | — |
| Benchmark indexes | ||
| Intelligence Index | 25.7 | 27.2Best |
| Coding Index | — | 51.5 |
| Capabilities | ||
| Reasoning | Yes | Yes |
| Tools | Yes | Yes |
| Vision | Yes | Yes |
| Structured output | Yes | Yes |
| Reasoning effort | — | — |
Public evaluations
Benchmarks
Independent evaluation results, with how each score ranks among the models in the Noumen catalog.
- Grok 4.20
- Grok Build 0.1
Intelligence Index
- Grok 4.2025.7
- Grok Build 0.127.2
Grok 4.20: Better than 62% of 326 scored models
Indexes
Coding Index
Composite of the coding evaluations
- Grok 4.20: —
- Grok Build 0.1: 51.5
Agentic work
GDPval-AAv2.1
Economically valuable occupational tasks, rated head to head
- Grok 4.20: —
- Grok Build 0.1: 1,065 Elo
Document reasoning
AA-LCRv1.1
Reasoning across long documents
- Grok 4.20: 69.0%
- Grok Build 0.1: 74.7%Top
Reasoning and knowledge
Humanity’s Last Exam
Expert-level questions across academic fields
- Grok 4.20: 34.5%
- Grok Build 0.1: 38.3%Top
GPQA Diamond
Graduate-level science questions
- Grok 4.20: 91.1%Top
- Grok Build 0.1: 89.5%
IFBench
Following precise output instructions
- Grok 4.20: 81.2%
- Grok Build 0.1: —
Legacy evaluations
Terminal-Bench Hard
Earlier terminal task suite
- Grok 4.20: 37.9%
- Grok Build 0.1: —
τ²-Bench Telecom
Tool use in a customer-support simulation
- Grok 4.20: 93.0%
- Grok Build 0.1: —
AA-LCR (unversioned)
Long-context reasoning, earlier grading
- Grok 4.20: 69.0%
- Grok Build 0.1: 74.7%Top
Scores from Artificial Analysis, updated Oct 26, 2026. Artificial Analysis
- Grok 4.20
- Grok Build 0.1
| Leaderboard | Grok 4.20 | Grok Build 0.1 |
|---|---|---|
| Vision Style Control · Entity Recognition | #7 · 1238.1 | Not in top 20 |
Ranks among Noumen catalog models on LMArena leaderboards. Only top-20 placements are listed.LMArena
- Grok 4.20
- Grok Build 0.1
| Leaderboard | Grok 4.20 | Grok Build 0.1 |
|---|---|---|
| FrontierMath v2 (Tiers 1–3) | #14 · 44.9% | Not in top 20 |
| GPQA Diamond | #12 · 89.3% | Not in top 20 |
Ranks among Noumen catalog models on Epoch AI leaderboards. Only top-20 placements are listed.Epoch AI
- Grok 4.20
- Grok Build 0.1
| Leaderboard | Grok 4.20 | Grok Build 0.1 |
|---|---|---|
| ARC-AGI-3 (Default harness) | #20 · 0.1% | Not in top 20 |
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
- 108.7 tok/s
- Faster than 65% of 256 models
- Time to first token
- 2.5 s
- Quicker than 61% of 256 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.
- 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
Related models
Other xAI models, starting with the same family.