Comparison · library pages read 23 September 2026
Mobile app design reference tools: Mobbin, its alternatives, and how a reference becomes a spec line
Before a screen is designed or a prompt is written, someone has to answer “how do good apps do this?” — onboarding, a paywall, an empty state, a settings screen. Reference libraries answer it with real screens from shipped apps. This page is for product managers, designers and founders writing the spec: Mobbin first, on its published numbers and its new MCP server; then the libraries that compete with it, each by what it indexes and whether Android is in it; then the two free primary sources; then how a reference goes into a PRD and a build prompt without copying anyone’s design.
Verified
What a reference library is for. Not inspiration in the decorative sense — evidence. A product manager specifying onboarding wants to see how twenty shipped apps sequence permission requests; a designer specifying a paywall wants the ten most common layouts and where the restore link sits; a founder wants to know what an empty state looks like in a category before writing “show a helpful empty state” into a spec. A library of real screens, organised by flow and pattern, is the fastest way to turn that into a sentence the builder can act on. The libraries differ in what they index (screens, flows, paywalls, store screenshots) and, for a mobile spec, in whether they cover Android at all — most do not. That column is the reason this page exists.
Mobbin
The largest published library, which is why it is first. Its home page on the read date shows 1,428 apps, 621,500+ screens and 323,900 flows, under the line “Discover real-world design inspiration.” The library is organised by app, screen and flow, filterable by pattern and UI element, and covers iOS, Android and web: its Android sections are browsable as their own “Android apps” and “Android flows” listings, which for a mobile spec means an onboarding or paywall pattern can be checked on both platforms in the same tool — the rest of the list mostly cannot do that.
Its newest feature is aimed at the way product people now build. From its MCP page: “Mobbin MCP is a design MCP server that connects your AI agents to 600,000+ real product screens, so what they build starts with what already works.” It is “Available on Pro & Team plans”, marked beta — “MCP has unlimited usage during beta. Limits will apply in future.” — and the page lists Claude, Cursor, Claude Code, ChatGPT, Codex, Manus, Grok, Figma and v0 as the agents it connects to. The practical meaning: an agent writing a screen can look up how shipped apps handle that screen before it writes. Pricing was not readable on the read date; check the pricing page.
The libraries that compete with it
Refero. Describes itself as the “largest collection of UI/UX references” for web and iOS. Organised by screens and flows with a searchable pattern index; no Android coverage stated on its pages. The closest to Mobbin in shape for iOS and web.
Screens Design. iOS only, 2,600+ apps, and the one library on this list built around monetisation: it indexes paywalls and onboarding flows and pairs them with revenue data, so a paywall pattern can be compared against what the app charging it earns. The former scrnshts.club, a library of App Store screenshots, now redirects to its store-screenshots section — the place to look when the spec item is the listing, not the app.
Nicelydone. Web only: 206,200+ screens from 500+ apps, organised by flow and component. Useful for a product with a web app beside the mobile apps, not for the phone screens themselves.
Page Flows and UX Archive. Both appear on every list of flow libraries, and neither could be read on 23 September 2026 — Page Flows returned an error, UX Archive did not respond — so this page makes no claims about their coverage or counts.
Also listed as alternatives on Product Hunt’s Mobbin-alternatives page: appshots, Growth.Design (annotated case studies rather than a screen library), Checklist Design and Magic Patterns. None of their pages was verified for this article.
The two free primary sources
Every library above is downstream of two documents that cost nothing and settle most spec arguments. Apple’s Human Interface Guidelines are the reference for iPhone and iPad — navigation, toolbars, sheets, and, since September, a section on designing for iPhone Duo — and Apple publishes design kits for them. Google’s Material 3 is the same for Android: components, layouts, adaptive guidance for foldables and tablets, with published design kits. When a reference library shows twenty apps doing something one way, the guideline says whether that is the platform convention or twenty apps copying each other — and a native app built on the platform’s own UI parts gets the convention for free. For a two-platform spec, the pair is the reference: the same feature has a HIG answer and a Material answer, and the spec should name both when they differ.
How a reference becomes a spec line, not a copy
A reference library is evidence for a pattern, not a source of screens to reproduce; another company’s design is theirs. The spec line that comes out of it names the pattern and the reason: “Onboarding: three screens, value first, permissions asked at the moment of use, not up front — the common pattern in the category.” “Paywall: annual plan preselected, monthly beside it, restore link below the button, terms visible before the button.” “Empty state: one sentence and one action, no illustration.”
Those lines go into the one-page PRD as the screen list and acceptance criteria. In a builder that takes the PRD as its first prompt — Modaal’s documentation says the first prompt takes “text, images, Figma links — whatever you provide”, and “You can attach a PRD, design doc, or screenshot with no text at all” — the reference does its work at the spec stage, and the agent writes a plan you approve before the SwiftUI and Jetpack Compose screens are built. A screenshot from a library attached as “this pattern, our content” is a legitimate prompt; “make it look like this app” is not the goal and not what a spec should say. Mobile app prototyping covers where in the three fidelities the reference is most useful; design to code tools covers the Figma route when the designer draws the screens first.
Reference libraries by platform coverage and what they index
| Library | iOS | Android | Web | What it indexes | Published size (23 Sep 2026) | Notes |
|---|---|---|---|---|---|---|
| Mobbin | Yes | Yes | Yes | Apps, screens, flows, patterns, UI elements | 1,428 apps · 621,500+ screens · 323,900 flows | MCP server on Pro & Team, beta; pricing not readable |
| Refero | Yes | Not stated | Yes | Screens, flows, patterns | Not quoted | “largest collection of UI/UX references” for web and iOS |
| Screens Design | Yes | No | No | Paywalls, onboarding, revenue data, store screenshots | 2,600+ apps | Former scrnshts.club redirects here |
| Nicelydone | No | No | Yes | Screens, flows, components | 206,200+ screens · 500+ apps | Web products only |
| Page Flows | Not readable | Not readable | Not readable | Not readable | Not readable | Page returned an error on the read date |
| UX Archive | Not readable | Not readable | Not readable | Not readable | Not readable | Site did not respond on the read date |
| Apple HIG · Material 3 | HIG | Material 3 | Both | Platform conventions, components, design kits | Free | The primary sources the libraries are downstream of |
From each library’s own pages as read on 23 September 2026. “Not stated” means the pages read do not say; “Not readable” means the site could not be read on that date. No ranking.
Frequently asked questions
The largest published one is Mobbin — 1,428 apps, 621,500+ screens and 323,900 flows on its home page on 23 September 2026 — and it is the only library on this page whose pages state iOS, Android and web coverage. Which is best for you depends on what you are specifying: Screens Design for paywalls with revenue data (iOS only), Nicelydone for web products, Refero for iOS and web screens and flows.
Of the libraries read for this page, Mobbin has browsable Android app and Android flow sections. Refero states web and iOS; Screens Design is iOS only; Nicelydone is web only; Page Flows and UX Archive could not be read on the read date. Google’s Material 3 guidelines are the free primary source for Android conventions.
Refero, Screens Design, Nicelydone, Page Flows and UX Archive are the established screen and flow libraries; Product Hunt’s alternatives list also names appshots, Growth.Design, Checklist Design and Magic Patterns, none of which was verified for this page. Apple’s Human Interface Guidelines and Material 3 are free and cover the conventions every library reflects.
In Mobbin’s words, “a design MCP server that connects your AI agents to 600,000+ real product screens, so what they build starts with what already works.” It is available on the Pro and Team plans, in beta with unlimited usage during the beta, and its page lists Claude, Cursor, Claude Code, ChatGPT, Codex, Manus, Grok, Figma and v0 as connected agents.
A reference library is evidence for a pattern — how apps in a category sequence onboarding or lay out a paywall — not a source of screens to reproduce; another company’s design belongs to it. Write the pattern and its reason into the spec, and build the screen with your own content and the platform’s own UI parts.
As a spec line per screen that names the pattern and the reason: “onboarding: three screens, permissions at the moment of use”; “paywall: annual preselected, restore link under the button, terms visible first”; “empty state: one sentence, one action.” Those lines are acceptance criteria the builder can check; the PRD prompt page has the full document.
The guidelines say what the platform convention is; a library shows how shipped apps in your category apply it, and where they deviate. For most spec questions the guideline settles the component and the library settles the flow. Both are needed when specifying one feature for iPhone and Android, because the convention differs and the spec should say so.
Yes, when the prompt says “this pattern, our content”. Modaal’s documentation says the first prompt takes “text, images, Figma links — whatever you provide” and that you can attach “a PRD, design doc, or screenshot with no text at all”; the agent writes a plan to approve before it builds the SwiftUI and Jetpack Compose screens. Free for one project; Pro is €9 per user per month billed annually and adds both platforms.
From reference to native screens, on both platforms
Write the pattern into the PRD, attach the reference, approve the plan. Modaal builds the SwiftUI and Jetpack Compose screens from one project with your own AI agent. Free for one project.
Keep reading
- The PRD prompt
Where the reference lines go.
- Mobile app prototyping: three fidelities
Where a reference is most useful.
- Design to code tools
The Figma route, sorted by output.
- Paywall tools for iOS and Android
The paywall pattern, then the vendor.
- Modaal for designers
Design once, ship native on both platforms.
- Figma to SwiftUI and Jetpack Compose
From the reference to the frame to the phone.