SaaS Platform DevelopmentWe build SaaS platforms
that extend, integrate,
and connect.
A platform is more than a product — it is a foundation built to grow, connect to the tools your customers use, and let others build on top through an API. We engineer that extensibility in from the start, as real software you own, from running a platform ourselves.
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.ioKompiPayeuropeanyachtbrokers.combusesforsale.comLoopa
What we buildA foundation to grow on,
not a fixed product.
Platforms are defined by what connects to them. We build the extensibility, integrations, and API that make a product a platform.
01
Extensible core
Architecture designed to grow into new workflows, not just one.
02
Integrations
Connecting to the tools your customers already use every day.
03
API layer
Where the model fits, letting customers and partners build on you.
04
Billing & roles
The subscription and permission machinery a real platform needs.
05
Owned by you
The full codebase, integrations, and API, no platform lock-in.
A platform is a product designed to be built on
The difference between a SaaS product and a SaaS platform is architectural, not cosmetic. A product does a defined set of things well. A platform is built to be extended — to support many workflows, to connect to the other tools its customers use, and often to expose an API so customers and partners can build on top of it. One is a finished thing; the other is a foundation.
That distinction shapes every decision underneath. A platform has to be designed, from the first architectural choices, for connection and growth: data models that anticipate extension, integration points built in rather than bolted on, and the discipline to keep the core clean enough that others can build against it. Retrofitting platform-ness onto a product that was not designed for it is painful, which is why the intent has to be there early.
So when you set out to build a platform rather than a product, the up-front architecture matters more, and getting it right is worth the care. We build with that foundation in mind, so the thing can genuinely grow into the platform you intend rather than hitting a wall a year in.
The connective tissuePlatforms live or die on what they connect to
What most distinguishes a platform in practice is its connections. Your customers already use other tools, and a platform earns its place by fitting into that ecosystem rather than demanding they abandon everything else for it. The integrations — to the software your customers rely on, to payments, to the services that make the product complete — are frequently what turn a product into a platform in the eyes of the people using it.
And where the model calls for it, an API takes this further: it lets your customers and partners build on top of your platform, extending it in ways you did not have to build yourself. That is the point at which a platform becomes a genuine foundation for an ecosystem, with its own gravity. Not every platform needs a public API, but for those that do, it is a defining piece.
This connective tissue is real engineering, and it has to be built deliberately and reliably, because other systems and other people come to depend on it. We build integrations and APIs as first-class parts of a platform, from the experience of running a platform that integrates many services in production.
ProofWe run a platform that connects many services
The clearest proof we can offer on platform development is that we run one. sellyourboat.io is a Wall & Fifth venture, and it is a platform in the real sense: it integrates multiple third-party services — mapping, payments, and a Claude-powered AI retrieval layer — into one coherent product, carrying over 12,000 listings across 18 countries.
Building and operating it meant solving the real platform problems: connecting many services reliably, keeping the architecture clean enough to extend, and keeping the whole thing performant and dependable in production while third-party systems come and go. Those are exactly the problems a SaaS platform build has to get right, and we have solved them on our own venture, with our own money on the line.
We have also delivered platform and integration work across our client roster including KompiPay. Building connected, extensible platforms is squarely what we do.
The buildProduction stack, fixed price, owned outright
We build SaaS platforms on a real production stack — Next.js, React, TypeScript, PostgreSQL, Stripe for billing, deployed properly — architected for extension, integration, and where needed an API. It is real, ownable software built to be a foundation, not a template you rent and outgrow.
We work to a fixed price. From 16,000 GBP for a focused first version — the core product on an extensible foundation, with accounts and billing — and from 30,000 GBP for a larger platform with integrations, an API, roles, and admin. Third-party usage — payment fees, infrastructure that scales with use — is passed through at cost, never marked up.
And you own all of it: the full codebase, the integrations, the API, the billing setup, handed over on delivery. No platform you keep paying, no licensing, no lock-in. Yours to run, change, and scale with us or any team you choose.
ProofWe run a real, connected platform
sellyourboat.io integrates mapping, payments, and AI into one platform at scale. We build yours from operating one.
12,000+
listings on our platform
3+
core services integrated
100%
code ownership, yours
PricingFixed price, scoped to the platform
A defined price for a defined build. Priced around the foundation you need, not screen count.
Platform MVP
from £16,000
The core product, accounts, billing, and an extensible foundation to grow from.
Extensive Build
from £30,000
Integrations, an API, roles, admin, and the architecture to support many workflows and partners.
Embedded Partner
from £8,000 /mo
Ongoing senior involvement once live: extending the platform, adding integrations, growing the ecosystem.
Build a platform
others can build on.
Tell us what your platform needs to connect and support. We will engineer the extensible foundation it grows from.