Web App DevelopmentWe build web apps
that reach everyone,
no install required.
A web app puts real functionality — accounts, dashboards, workflows — in front of anyone with a browser, instantly, on any device. We build them as production software, on a modern stack, fixed-price and owned by you. It is what we build our own platforms on.
app.yourmarketplace.com
Live marketplace
Two-sided liquidity, one platform
Supply and demand, matched. Listings, search, payments, and trust — built to move volume.
Recent activity
NNew listinglive
BBroker onboardedverified
EEnquiry matchedsent
PPayment cleared£4,200
Platforms and marketplaces we have built and worked on
sellyourboat.ioKompiPaybusesforsale.comeuropeanyachtbrokers.comLoopa
What we buildReal applications,
running in the browser.
Not a website, not a template — a real app with logins, data, and functionality, that reaches everyone with no download.
01
No install, total reach
Anyone with a browser, any device, instantly — nothing to download.
02
Real functionality
Accounts, dashboards, workflows — an app, not a brochure.
03
Instant updates
Ship once, everyone has the latest version immediately.
04
PWA-ready
Installable and near-native where it helps, without two native builds.
05
Owned by you
The full codebase, handed over. No licensing, no lock-in.
For most products, the web app is the smartest first move
There is a reflex among founders to assume a serious product needs a native mobile app. Often it does not — and reaching for one first is a common, expensive mistake. A web app reaches everyone instantly, on every device, with no install and no app-store gatekeeping. Nothing to download, no approval to wait on, one build serving desktop and mobile browsers alike. For validating a product and reaching the most people fastest, that is hard to beat.
Native mobile genuinely earns its place when the usage is frequent and on-the-go, when push notifications drive the behaviour, when being one tap away on the home screen changes how often people return. But plenty of products are not that, and building native for them means paying more to reach fewer people. We would rather talk you into the build that fits than the one that sounds impressive.
So for most founders we recommend web first: reach and validate on the web, then add native mobile where real usage justifies it. The sequence saves money and gets you in front of people sooner.
A real appA web app is functionality, not a fancy website
The important distinction is not web versus native — it is website versus application. A website presents information; a web app lets people do things. Accounts, dashboards, real-time data, workflows, tools that hold state and respond to what the user does. When we build a web app, we are building software that happens to run in a browser, not a prettier brochure.
That matters because the engineering underneath is real: authentication, data models, application logic, performance, the same production concerns as any serious software. A web app that people log into and rely on has to be built like an app, not assembled like a marketing site. We build it that way, on the same production stack we use for everything else.
This is the difference between something that demos well and something people actually use every day. We build for the second.
ProofWe build and run web apps at scale
The most useful proof we can offer on web apps is that we run one at scale ourselves. sellyourboat.io is a Wall & Fifth venture: a full production web platform and marketplace we built and operate, with over 12,000 listings, real accounts and tooling, search, and a Claude-powered AI layer — a genuine web application doing real work for real users.
Building and running it means we have made every real decision a serious web app involves — architecture, performance, data, reliability — with our own money and reputation on the line, and kept it running in production. So we build your web app from operating experience, not from theory.
We have also delivered web platform work for busesforsale.com, europeanyachtbrokers.com, and others. Real web applications are simply what we build.
The buildProduction stack, fixed price, owned outright
We build web apps on a modern production stack: Next.js, React, and TypeScript, with PostgreSQL behind them, deployed properly. It is the exact foundation under our own products, chosen because it is genuinely good — fast, robust, and pleasant to build and extend — not because it is cheap or fashionable.
We work to a fixed price so you are never exposed to an open-ended hourly meter. From 16,000 GBP for a focused web app MVP, from 30,000 GBP for a larger build with more users, features, and integrations. Third-party usage — payments, AI inference — is passed through to you at cost, never marked up.
And you own all of it: the full codebase and the infrastructure, handed over on delivery. No platform you keep paying to keep your product alive, no licensing, no lock-in. Yours to run, change, and scale with us or any team you choose.
ProofWe run a real web app at scale
sellyourboat.io is a Wall & Fifth web platform with 12,000+ listings, real tooling, and an AI layer. We build yours from operating one.
12,000+
listings, live web app
100%
code ownership, yours
PricingFixed price, scoped to the app
A defined price for a defined build. You know the number before we start.
Web App MVP
from £16,000
A focused custom web app with the core flows that make it real and ready to launch.
Extensive Build
from £30,000
Multiple user types, richer features, integrations, and admin, built to scale.
Embedded Partner
from £8,000 /mo
Ongoing senior involvement once live: shipping, evolving, and growing the product.
Build a web app
that reaches everyone.
Tell us what it needs to do and who it is for. We will build a real web application — fast, reachable, and yours.