The answer is somewhere between free and £50,000 and that range is not a joke.
App prototype costs vary this wildly because "prototype" means genuinely different things depending on who's asking, what stage they're at, and what the prototype is supposed to do. A clickable Figma mockup that simulates a user journey is a prototype. A no-code proof of concept built over a weekend is a prototype. A fully functional pre-launch product is sometimes called a prototype by optimistic founders who don't want to admit they're building the actual thing.
What you pay depends on which of these you're actually building — and whether that matches what your situation actually requires.
This article breaks it down properly.
Wireframes and Low-Fidelity Mockups: £0 – £2,000
A wireframe is a skeletal layout of an app screen. No colour, no branding, no working interactions — just boxes and text indicating where things go and how screens relate to each other.
Low-fidelity mockups exist to communicate structure and flow before any visual design or development work happens. They're used in early-stage discussions, internal planning, and basic user feedback sessions.
You can produce wireframes yourself using free tools — Balsamiq, Whimsical, even PowerPoint at a stretch. If you hire a UX designer to produce them professionally, expect £1,000–£2,000 for a simple app and more for something complex.
When this is enough: When you need to communicate an idea clearly to stakeholders, developers, or potential investors, and the primary question is "does this structure make sense?" rather than "does this work?" These are planning documents, not testable products.
Interactive UI Prototype: £2,000 – £8,000
A step up from wireframes: high-fidelity designs with real visual design, brand elements, and clickable interactions simulating the user experience. Built in Figma or a similar tool, these look like the finished app and behave like it on the surface — but there's no real code, no real data, no real backend.
Interactive prototypes are the most undervalued tool in early product development. They let you test the user experience, gather meaningful feedback, refine the design, and validate assumptions about flow and usability — before a developer touches anything. A problem discovered here costs hours to fix. The same problem discovered in development costs days. Found after launch: weeks and a side order of user frustration.
The cost is primarily design time. A simple two to three user journey app prototype from a competent UX/UI designer: £2,000–£4,000. A more complex product with multiple user roles, intricate flows, and polished visual design: £4,000–£8,000.
When this is enough: When you need to test and validate the user experience before committing to development costs. When you're showing investors or early adopters what the product will be. When you want alignment on design before the build begins. For most pre-development stages, this is the right prototype.
No-Code / Low-Code Prototype: £2,000 – £15,000
A functional prototype built on platforms like Bubble, Webflow, or Glide — real interactions, real data, real users can actually use it. This isn't a simulation; it's a working product built without traditional development.
The cost is lower than custom development because you're working within the platform's existing infrastructure rather than building from scratch. What takes a development team ten weeks can sometimes be produced in two on a no-code platform, within its constraints.
The relevant constraints: the logic has to fit what the platform supports, performance at scale is limited, and migrating to custom development later is effectively a rebuild. For validation purposes — getting something in front of real users quickly to test whether the idea works — these constraints often don't matter yet.
DIY on a no-code platform: platform subscription (often free to start) plus your time. Hiring someone to build it: £2,000–£6,000 for a focused prototype, up to £15,000 for something more capable.
When this is enough: When you're past the design validation stage and need to test whether people actually use and pay for the product. When you want to generate evidence of demand before investing in a full custom build. When your requirements fit within the platform's capabilities.
Custom-Code MVP (Often Called a Prototype): £15,000 – £60,000+
Here's where it's worth being honest about terminology.
A lot of what founders call a "prototype" is actually an MVP — a functional product built in real code, on real infrastructure, designed to be extended and scaled. Not a simulation, not a no-code experiment — the actual product, scoped lightly for the validation stage.
This costs what custom development costs because it is custom development. The price reflects the fact that you're building something real: a design phase, a development phase, QA, deployment, the works.
The range is wide because scope drives everything. A focused single-journey app — one core workflow, standard integrations, clean UI — can be built for £15,000–£25,000 with the right partner using AI-native development processes. A product with multiple user roles, complex backend logic, payment processing, and several integrations sits at £30,000–£60,000. Anything with regulatory requirements, real-time features, or significant technical complexity goes beyond that.
When this is what you actually need: When you've validated demand and you're building the real product, not testing an idea. When you need something investors can scrutinise. When users will trust it with real data. When you intend to build on it after launch rather than rebuilding it.
What Drives the Cost of App Protoypes
Regardless of which type of prototype you're building, four variables move the price in either direction.
Scope
The single biggest driver. Every screen, every user journey, every integration, every feature adds to the work. An app prototype with two core user journeys costs a fraction of one with eight. Defining the minimum required to test the core hypothesis — and holding to it — is the most effective cost control available.
Design complexity
A prototype with placeholder visuals and standard components costs less than one with custom illustrations, complex animations, and a fully developed design system. For a validation prototype, design sophistication matters less than clarity. For an investor demo, it matters more.
Who builds it
A freelancer on a marketplace, an offshore agency, a boutique studio, a UK-based agency with London overheads — these all produce different cost structures for comparable output. The price difference between a traditional UK agency and a quality development partner using AI-native processes and distributed talent is significant. Output quality depends on vetting and process, not on the billing rate.
Timeline pressure
Rushed prototypes cost more. Emergency timelines, late-scope changes, and compressed testing windows all add to the work. A realistic timeline — typically four to eight weeks for a well-scoped interactive prototype or no-code build — produces both better work and more predictable cost.
The Cost of Making a Prototyping Mistake
The most expensive prototype mistake isn't overpaying for one. It's building the wrong type for the stage you're at.
Building a custom-coded product to test whether anyone wants it — before any design validation, before any user research, before a no-code prototype would have told you what you needed to know for a fraction of the cost — is the mistake that consistently produces the most expensive and most demoralising outcomes in early product development.
The reverse mistake exists too: spending months on an interactive Figma prototype when what you actually need is something functional that real users can try with real data, because the interaction design looked right but the core assumption about user behaviour was wrong.
The prototype should match the question you're trying to answer.
"Does this make sense as a concept?" → Wireframes or interactive UI prototype. "Will people actually use this?" → No-code functional prototype. "Is this worth building properly?" → A well-scoped MVP.
Getting this sequencing right is the most valuable thing you can do before spending anything on development.
What Octogle Builds for Founders
We work with founders at the prototype and MVP stages — specifically the later stages, where something functional needs to be built properly rather than simulated.
Our interactive design work produces the UI prototype that validates the experience before development begins. Our AI-native development team then builds the functional product — properly scoped, properly built, on a timeline and at a cost that reflects how development actually works in a team that uses modern tooling effectively.
We don't build Figma mockups and call them done. We don't build no-code prototypes and call them MVPs. We tell you honestly which stage you're at, what type of prototype makes sense for your current question, and what it costs — before anyone commits to anything.
If you're trying to work out what you actually need and what it should cost — start with a conversation.
Octogle Technologies builds interactive app prototypes and custom MVPs for founders who are ready to build properly — scoped honestly, priced clearly, delivered in weeks not months. Tell us what you're building.
