Gemini 3.1 Pro preview vs Grok 4.20 Multi Agent beta 0309

Gemini 3.1 Pro preview vs Grok 4.20 Multi Agent beta 0309: Grok 4.20 Multi Agent beta 0309 is cheaper by 50% on average. Gemini 3.1 Pro preview from Google Vertex AI (1,048,576-token context, reasoning, tool calls) vs. Grok 4.20 Multi Agent beta 0309 from xAI (2,000,000-token context, reasoning, tool calls). Use Agent Command Center to A/B both in shadow mode and pick the winner per workload.

Side-by-side cost

Live workload comparison

Same workload run through both models. The cheaper one is highlighted.

Input tokens / request3,000

02,000,000

Output tokens / request400

0200,000

Requests / day5,000

01,000,000

Gemini 3.1 Pro preview

Google Vertex AI

$1,644/mo

Input $2.00/M · Output $12.00/M

Grok 4.20 Multi Agent beta 0309Cheaper

xAI

$1,278/mo

Input $2.00/M · Output $6.00/M

At this workload, Grok 4.20 Multi Agent beta 0309 is 22% cheaper than Gemini 3.1 Pro preview — a savings of $365/month ($4,383/year).

Production recipe — Agent Command Center

strategy: cost-optimized
primary:
  model: grok-4-20-multi-agent-beta-0309
  provider: xai
fallback:
  model: gemini-3-1-pro-preview
  provider: vertex-ai
shadow: { sample_rate: 0.05 }   # mirror 5% of traffic to compare quality live

Get started free →Routing docs ↗

	Gemini 3.1 Pro preview Google Vertex AI	Grok 4.20 Multi Agent beta 0309 xAI
Input price	$2.00/M	$2.00/M
Output price	$12.00/M	$6.00/M
Context window	1,048,576	2,000,000
Max output	65,536	2,000,000
Function calling	✓	✓
Vision	✓	✓
Audio input	✓	—
Reasoning	✓	✓
Prompt caching	✓	✓
Structured output	✓	—
Pricing verified	May 12, 2026	May 12, 2026