Fluid UI

Overview

Fluid UI is a web-based mockup and prototyping tool for people shaping mobile app ideas into shareable, interactive demonstrations. It is best suited to solo designers who need a quick path from screens to feedback, and to small teams that want to prototype together. Its combination of interactive previews and review tools is compelling, though the paid plans’ user-license limits matter for teams.

Projects can be created, edited, previewed, shared and exported. Interactions such as taps, swipes and clicks turn screens into a navigable prototype, while built-in component libraries and page effects help communicate how a product might look and behave.

Key features

• Component libraries: More than 2,000 components span Material Design, iOS, Windows and wireframe libraries. That breadth gives designers several familiar starting points without limiting the tool to one visual system.
• Interactive prototypes: Taps, swipes, clicks and other gestures can connect screens in web and mobile prototypes. Pop-in, fade-in, flip and show effects add motion; these are useful for explaining transitions, but do not replace a finished product interface.
• Collaboration and review: Cloud-saved projects support real-time collaborative prototyping. Reviewer mode adds shared click-throughs, chat, annotations and comments, and Fluid UI supports remote user-testing sessions. This makes the service more than a screen-building tool when stakeholder feedback is part of the workflow.
• Saving and security: Projects save continuously, with restoration from any save in the editor; daily, weekly and monthly backups are also performed. Pages use 256-bit encryption for data sent to the service. Realex Payments processes and stores card details rather than Fluid UI’s own servers.
• Support and hosting: Built-in live chat support is available 16 hours a day. Servers run in a Rackspace US data center, which the privacy notice describes as GDPR compliant; account-data deletion can be requested by email.

Pricing

Fluid UI uses a freemium model, with a free lifetime account and paid plans starting at $8.25/mo. A free trial is available. The paid-plan prices below are monthly:

• Free: Free forever. This is the no-cost entry point, but the plan information gives no project or user allowance to weigh against paid tiers.
• Solo — 8.25 USD per month: Five active projects, one user license and unlimited reviewers. It suits an individual who wants to share work for feedback, but the single license is not a shared editing allowance.
• Pro — 19.08 USD per month: Ten projects, one user license and unlimited reviewers, plus export, print and comment. Choose it when those output and feedback options matter; it still licenses only one user.
• Team — 41.58 USD per month: Unlimited projects, five users, unlimited reviewers, export, print and comment, and real-time team collaboration. It is the clearest fit for a small group editing together, though the five-user allowance sets a firm scale boundary.

Solo and Pro keep the project owner count to one, so reviewers can respond without becoming collaborators. Team raises that allowance to five and removes the project cap. Compare those limits with the number of people who need to edit, not just view, before choosing a tier.

Platforms

Fluid UI runs in Firefox and Chrome and offers an installable desktop client, plus Android and iOS preview apps. Its platform coverage includes Android, iOS, Linux, macOS, web and Windows, giving teams several ways to access work and preview mobile prototypes.

Who it's for

Fluid UI suits designers, entrepreneurs, developers, product managers and educators who need to communicate an app idea through screens, interactions and review. Solo and Pro make sense when one person owns the prototype and others mainly comment; Team is more appropriate when several colleagues need to collaborate in real time. It is less attractive for groups that need more than five editing licenses on the listed team tier.

Pros and cons

• Pro: A broad set of 2,000-plus components across four design and wireframe libraries helps cover varied interface concepts.
• Pro: Interactive gestures, page effects, shared click-throughs and remote testing connect prototyping with feedback in one workflow.
• Pro: Unlimited reviewers across paid plans let a solo license holder gather input without buying a seat for every reviewer.
• Con: Solo and Pro each include only one user license, so they do not support multiple editors despite unlimited reviewers.
• Con: Team includes five users; larger groups should confirm that allowance meets their needs before committing.

Alternatives

For a broader category comparison, browse Wireframing Software, Game UI Design Software, UI design tools and Prototyping Software.

• Justinmind is worth considering for a free starting point with one project, unlimited screens and viewers, and UI design and wireframing.
• Mockplus offers a free Basic plan with 10 users and 10 active projects, which may suit a group prioritizing a larger free team allowance.
• Visily has a free Starter tier with 300 AI credits per month and standard AI design, making it an alternative for readers seeking AI-assisted design.
• Draftium provides a free plan with up to three prototypes, 50 generic templates and unlimited editing, a useful alternative when those caps fit the project.
• Frame0 offers a free plan with no time limit and 1,500 icons across Windows, macOS and Linux.
• Mokkup.ai has a free tier with one editable project, three screens per project, 25 coins and 50 editable templates.
• Uizard offers a free plan capped at two projects, five screens per project and 400 components, alongside three AI generations per month.
• MockFlow is another freemium option for readers comparing design tools.

Verdict

Fluid UI is a strong fit for solo creators and small product teams that need interactive mobile mockups, structured feedback and collaborative prototyping in one service. Its reviewer allowance and component range are useful strengths; the one-user Solo and Pro licenses, followed by Team’s five-user cap, are the main reasons larger editing groups should look elsewhere.