Arco

About Arco

Arco is a native macOS app for asking one question to many models at once and then deciding which answer to trust. You bring your own OpenRouter API key, which gives it access to more than four hundred models from frontier to open-weight, and you pay OpenRouter's per-token rates directly with no markup from Arco. Type a prompt once and it broadcasts to every selected model in parallel, laid out in a configurable one-, two-, three-, or four-column grid. The feature that turns a comparison view into a decision tool is Summarize: it sends every model's response to a judge model of your choosing and streams back a structured breakdown of where the models agree, where they diverge, and which answer to act on — and the vendor makes the point that disagreement between models is usually exactly the edge case a single-model workflow would have missed. You can regenerate the summary with a different judge and copy it in one click. Privacy is a core claim rather than a footnote: every conversation is stored locally on the device and never uploaded, with no Arco servers in the path. The positioning against the category is explicitly about the business model — most multi-model comparison tools charge a monthly subscription you underuse, while Arco is a free tier plus an optional perpetual license. It requires macOS 13 Ventura or later on Apple Silicon.

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