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Specifications
Context window
1M—
API pricing
Input price
$4.00—
Output price
$20.00—
Cached input price
$0.20—
Cheapest input
$4.00Amazon Bedrock—
Cheapest output
$20.00Amazon Bedrock—
Benchmarks
BullshitBench v2
63%19%
Overview
CompanyAnthropicSpaceXAI
Release dateSep 22 2026Nov 19 2025
AccessClosedClosed
Model detailsView modelView model

Frequently asked questions

Claude Opus 5.5 leads Grok 4.1 Fast on 1 of the 1 benchmark they both report (BullshitBench v2). Only Claude Opus 5.5 has a verified first-party API price: $4.00 per million input tokens and $20.00 per million output tokens. No pay-as-you-go API rate is tracked for Grok 4.1 Fast. Grok 4.1 Fast shipped 307 days before Claude Opus 5.5, so benchmark comparisons should account for the intervening progress.

Published specifications for these two models are limited — see each model page for the latest details.

On BullshitBench v2, Claude Opus 5.5 leads at 63% vs Grok 4.1 Fast at 19%.