Ask every model. Pick the best answer. All staying private.
Choose from 400+ AI models and compare them side by side to know which answer to trust. Use your own OpenRouter API key. All data stays on your device.
macOS 13 Ventura or later · Apple Silicon · Free to start
Everything you need to decide
One prompt. Every answer. A clear picture of which model to trust.
Broadcast to all models
Type once, send to every model simultaneously. No copying, no pasting, no opening separate chat sites. Get answers from all your favorite models in one place.
Fully private
Every conversation stays on your device, stored locally and never uploaded. No servers storing your data, no middlemen in between. You're always in control.
AI-powered summary
Generate a structured comparison of all responses instantly. See where models agree, where they differ, and decide which answer to use, in seconds.
400+ models available
Access 400+ models on OpenRouter, from frontier models to open source alternatives. All with a single API key.
Flexible layouts
Arrange panes in 1, 2, 3, or 4-column grids. Focus on what matters, hide the rest. Your workspace, your way.
Pay only what you use
No subscription required. You pay OpenRouter's per-token rates directly. No hidden fees, no markup.
Up and running in minutes
Three steps and you're seeing which model gives the best answer.
Showing step 1: Get an OpenRouter key
One click to a confident decision
When multiple models reply, Arco's Summarize feature sends all their responses to a judge model of your choice. You get a structured breakdown: where models agree, where they diverge, and which answer you should act on. When models disagree, that's often the edge case you'd miss with just one.
- Picks any model from your library as the judge
- Streams the comparison in real-time
- Copy the summary to clipboard in one click
- Regenerate anytime with a different judge model
## Key Differences
## Best Answer
## Recommendation
Who makes better decisions with Arco
Anyone who needs to know which answer to act on, not just which model to ask.
Developers
Debug code, weigh architecture advice from multiple models, and commit to the approach that actually holds up.
Writers
Generate multiple drafts, compare tone and style, and pick the version that fits your voice.
Researchers
Cross-check summaries, surface different perspectives, and decide which interpretation is backed by the strongest reasoning.
Business Teams
Draft reports, generate exec summaries, and pressure-test strategy ideas so you present the version you can defend.
How Arco compares
See how Arco stacks up against other multi-model apps, and why the comparison workflow matters more than any single model.
Full power. Simple pricing.
Forever
Compare from 400+ AI models
Up to 3 saved conversations
Your data stays on your device
Unlimited
Compare from 400+ AI models
Unlimited saved conversations
Your data stays on your device
One payment, perpetual license
1 year of updates & support included
Optional renewal at a discount
Works on 1 macOS Device
Frequently Asked Questions
Explore our comprehensive FAQ to find quick answers to common inquiries. If you need further assistance, don't hesitate to contact us for personalized help.
Have more questions? Reach out to [email protected]
Start making better decisions today
Download Arco free. Bring your own OpenRouter key and you're comparing answers in under two minutes.
Free to start · macOS 13+ · Apple Silicon