Best Flatsies Alternatives & Competitors in 2025

Red Pen lets you upload your design, share a short URL, and get live, annotated feedback super-fast.

Key Red Pen features:

Real-Time Collaboration User-Friendly Interface Feedback Annotations File Management

The all-in-one design sharing, collaboration, workflow and app prototyping platform.

Key Savahapp features:

User-Friendly Interface Collaboration Features Prototype Integration Scalability

paid Free Trial $8.0 / Monthly

RealityMAX is the AI-powered 3D design collaboration platform, 100% online. Cooperate remotely with your colleagues on 3D projects and easily share your work with clients. Create Web3D and AR experiences in a snap, without a line of code.

Key RealityMAX features:

AI image enhancer Upload multiple 3D models Edit 3D model materials Change 3D model texture

Visit website freemium $40.0 / Monthly (Pro with up to 500 GB of storage space)

Text and Facebook messaging from Slack.

Prototyping and collaboration for design teams.

Key Invision features:

Collaborative Features Prototyping Integrations User Testing

A service that allows designers and clients to annotate and collaborate on images in real time.

Feedback, prototyping and collaboration for designers.

Key Viewflux features:

User-Friendly Interface Collaborative Features Design Prototyping Centralized Design Handoff

Turn sketches, mockups and designs into web, iPhone, iOS, Android and Apple Watch app prototypes.

Key Marvel features:

User-Friendly Interface Real-Time Collaboration Prototyping Features Integration with Other Tools

Version control, collaboration and online coding for devs.

ZipBoard is a web-based visual bug tracking & issue tracking tool that helps developers, testers and project managers collaborate during website and elearning development.

Key zipBoard features:

Collaborative Annotation Centralized Feedback Visual Bug Tracking Ease of Use

Adobe XD is an all-in-one UX/UI solution for designing websites, mobile apps and more. .

Key Adobe XD features:

User Interface Integration with Adobe Ecosystem Prototyping and Animation Collaboration Tools

A free platform for creating beautiful website and mobile app specification documents for your team. No more word templates!

Key Specfox features:

Ease of Use Collaboration Features Time Efficiency Integration

What's next after wireframes? Visual Design and Notism.

Key Notism features:

Real-Time Collaboration Visual Feedback Features Task Management Integration Version Control

ProofHQ provides a medium for co-workers to annotate and collaborate before producing a clean, finished output.

Key Proof HQ features:

Streamlined Collaboration Centralized Feedback Version Control Integration Capabilities