Compare AI models

Specifications
Context window
1M128k
API pricing
Input price
$2.00—
Output price
$10.00—
Cached input price
$0.20—

These models have no shared benchmark scores.

Overview
CompanyAnthropicOpenAI
Release dateSep 28 2026Feb 12 2026
AccessClosedClosed
Model detailsView modelView model

Frequently asked questions

Claude Sonnet 5.5 and GPT-5.3-Codex-Spark don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Only Claude Sonnet 5.5 has a verified first-party API price: $2.00 per million input tokens and $10.00 per million output tokens. No pay-as-you-go API rate is tracked for GPT-5.3-Codex-Spark. GPT-5.3-Codex-Spark shipped 228 days before Claude Sonnet 5.5, so benchmark comparisons should account for the intervening progress.

Context windows are 1M (Claude Sonnet 5.5) vs 128k (GPT-5.3-Codex-Spark).

Direct benchmark comparisons are unavailable — Claude Sonnet 5.5 and GPT-5.3-Codex-Spark don't publish scores on any of the same benchmarks.