What it does
Proto.io is a browser-based prototyping tool with UI components, variables and timeline animation. It supports web and mobile previews, feedback links and offline exports. New accounts receive a 15-day trial and can then switch to a limited Free plan with one project and five screens.
Build and animate in the browser
Proto.io provides UI components for iOS, Android and web interfaces. Events and actions define responses, while timeline controls adjust animation timing, easing and duration. Designs can be imported from Figma, Sketch, Adobe XD or Photoshop.
Subscription allowances
| Plan | Monthly price shown | Users | Active projects |
|---|---|---|---|
| Freelancer | $29/month | 1 | 5 |
| Startup | $49/month | 2 | 10 |
| Agency | $99/month | 5 | 15 |
| Corporate | $199/month | 10 | 30 |
Annual billing has lower monthly equivalents. All paid plans include unlimited reviewers and HTML, PNG and PDF exports. A share link supports comments, while a snapshot preserves the prototype at a particular stage.
Sign up for the trial without a credit card. After it ends, you can choose the Free account instead of subscribing: one user, one active project, five screens and 10 MB storage. It has restricted features, so it is not equivalent to the full trial. Paid plans are the relevant choice for ongoing review and export workflows.
Strengths
- Timeline controls expose easing, duration and animation timing
- Paid plans include unlimited reviewers
- A limited Free account remains available after the trial
Watch out for
- Free access allows only one active project and five screens
- The full export and review workflow belongs to paid plans
Best for
- Browser-based prototyping of web and mobile interactions
Sources
- Proto.io prototyping features (Oct 27, 2026)
- Proto.io pricing and Free account (Oct 27, 2026)