Compare AI models

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
Next.js Evals
97%58%
Overview
CompanyAnthropicSpaceXAI
Release dateSep 22 2026Mar 19 2026
AccessClosedClosed
Model detailsView modelView model

Frequently asked questions

Claude Opus 5.5 leads Composer 2 on 1 of the 1 benchmark they both report (Next.js Evals). 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 Composer 2. Composer 2 shipped 187 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 Next.js Evals, Claude Opus 5.5 leads at 97% vs Composer 2 at 58%.