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
Input priceWhat you pay for everything you send the model — your question, plus any documents or earlier conversation you include with it.
$10.00—
Output priceWhat you pay for the text the model writes back. It is normally the dearer half: producing an answer costs more than reading one.
$50.00—
Cached input priceA reduced rate for text you send over and over. If every request starts with the same instructions or the same document, the provider keeps a copy ready and charges less to read it again.
$0.25—
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.
$10.00Amazon Bedrock—
Cheapest outputLowest output rate across every provider on OpenRouter, the lab included. May come from a different provider than the cheapest input.
$50.00Amazon Bedrock—
$4,500Anthropic list price—
These models have no shared benchmark scores.
Overview
CompanyAnthropicOpenAI
Release dateSep 1 2026Feb 12 2026
AccessClosedClosed
Model detailsView modelView model

Frequently asked questions

Claude Fable 5.1 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 Fable 5.1 has a verified first-party API price: $10.00 per million input tokens and $50.00 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 201 days before Claude Fable 5.1, so benchmark comparisons should account for the intervening progress.

Context windows are 1M (Claude Fable 5.1) vs 128k (GPT-5.3-Codex-Spark).

Direct benchmark comparisons are unavailable — Claude Fable 5.1 and GPT-5.3-Codex-Spark don't publish scores on any of the same benchmarks.