Ask once, reach every model, all staying private.
Choose from 400+ AI models and compare them side by side in one window with your own OpenRouter API key, while keeping all data on your device.
macOS 13 Ventura or later · Apple Silicon · Free to start
Everything in one place
Stop juggling separate chat sites. One prompt. Every answer. Instantly.
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 find the best answer 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 comparing answers from the world's best models.
Showing step 1: Get an OpenRouter key
One click to the best answer
When multiple models reply, Arco's Summarize feature sends all their responses to a judge model of your choice. You get a structured breakdown of what each model said, where they agree, and which answer is strongest.
- 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 uses Arco
Anyone who wants better answers faster, without juggling multiple chat sites.
Developers
Debug code, compare architecture advice, and evaluate API design suggestions from multiple models at once.
Writers
Generate multiple drafts, compare tone and style, and pick the version that fits your voice.
Researchers
Cross-check summaries, surface different perspectives on a topic, and validate sources across models.
Business Teams
Draft reports, generate exec summaries, and pressure-test strategy ideas with diverse AI perspectives.
How Arco compares
See how Arco stacks up against other multi-model apps and against using ChatGPT or Claude on their own.
Send to all models at once
Arco
Comparison apps
Chat services
Structured AI summary
Arco
Comparison apps
Some appsChat services
Your data stays local
Arco
Comparison apps
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Any model via one API key
Arco
Comparison apps
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No monthly subscription
Arco
Comparison apps
Chat services
400+ models available
Arco
Comparison apps
Fewer modelsChat services
Start at full speed !
Free
Compare from 400+ AI models
Up to 2 saved conversations
Your data stays on your device
Pro
Compare from 400+ AI models
Unlimited saved conversations
Your data stays on your device
One payment, no recurring charges
Free updates included
Works on 1 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 comparing models today
Download Arco free. Bring your own OpenRouter key and you're ready in under two minutes.
Free to start · macOS 13+ · Apple Silicon