Top 20 Alternatives to Fluid UI in UI & UX Prototyping Software

Fluid UI is a web‑based prototyping tool that lets designers create interactive mock‑ups without coding. Looking for other UI/UX prototyping platforms? Below are 20 popular alternatives.

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Top Competitors to Consider
#2 Figma

Collaborative, cloud‑based design tool with real‑time editing, vector editing, and interactive prototyping.

All‑in‑one UX/UI solution from Adobe offering design, repeat grids, auto‑animation, and voice prototyping.

#4 Sketch

Mac‑only vector design app focused on UI design, with extensive plugin ecosystem and prototyping features.

Web‑based platform for creating clickable prototypes, design systems, and collaborative feedback.

Powerful wireframing and high‑fidelity prototyping tool with conditional logic, adaptive views, and documentation.

#7 Marvel

Simple online prototyping suite with design, handoff, and user testing integrations.

#8 UXPin

Design system‑centric prototyping tool that supports interactive states, code components, and usability testing.

#9 Framer

React‑based design tool for high‑fidelity interactive prototypes with real code components.

#10 Balsamiq

Low‑fidelity wireframing app that mimics hand‑drawn sketches for rapid concept iteration.

#11 Proto.io

Browser‑based platform for creating fully interactive mobile and web prototypes without coding.

Comprehensive prototyping tool with UI libraries, conditional navigation, and integration with popular design apps.

#13 Penpot

Open‑source, web‑based design and prototyping tool that supports SVG editing and collaborative workflows.

Free macOS app from Facebook for creating interactive UI prototypes with advanced animation capabilities.

#15 Principle

Mac‑only app for designing animated and interactive UI mock‑ups, ideal for micro‑interactions.

#16 Mockplus

All‑in‑one design, prototyping, and collaboration tool with drag‑and‑drop components and rapid mock‑up creation.

#17 Webflow

Visual web‑design platform that lets designers build responsive sites and interactive prototypes with production‑ready code.

#18 Zeplin

Design handoff and collaboration tool that turns UI designs into specs, assets, and interactive prototypes.

Open‑source animation library for React that enables developers to prototype and build interactive UI components directly in code.

Fast web‑based prototyping suite with user testing, design handoff, and integration with popular design tools.

#21 Fluid UI

Web‑based drag‑and‑drop prototyping platform (included for reference) offering interactive mobile and web mock‑ups.