Compare AI models

Specifications
Context windowHow much text the model can hold in mind at once — your question, any documents you attach, the conversation so far, and its own reply. Go past it and the earliest part falls out of view.
1M128k
API pricingUSD per 1M tokens · lower wins
Cheapest inputLowest input rate across every provider on OpenRouter, the lab included. The cheapest endpoint may run a quantised build or a shorter context — see "Available from" on the model page.
$1.25Meta—
Cheapest outputLowest output rate across every provider on OpenRouter, the lab included. May come from a different provider than the cheapest input.
$4.25Meta—
$463Meta—
These models have no shared benchmark scores.
Overview
CompanyMetaOpenAI
Release dateSep 2 2026Feb 12 2026
AccessClosedClosed
Model detailsView modelView model

Frequently asked questions

Muse Spark 1.3 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. GPT-5.3-Codex-Spark shipped 202 days before Muse Spark 1.3, so benchmark comparisons should account for the intervening progress.

Context windows are 1M (Muse Spark 1.3) vs 128k (GPT-5.3-Codex-Spark).

Direct benchmark comparisons are unavailable — Muse Spark 1.3 and GPT-5.3-Codex-Spark don't publish scores on any of the same benchmarks.