Custom Web App Development
Bespoke web apps your team actually wants to use.
Internal tools, client portals, quoting and booking apps, and lightweight SaaS MVPs — built in 4–10 weeks, fixed-fee, with 100% code ownership. The interface your people log into; the AI workflow is what runs behind it.
- Per build
- 4–10 wks
- Code ownership
- 100%
- Per-seat SaaS fees
- £0
Outcomes
What changes for your business
A cockpit, not a spreadsheet
One branded UI replacing three spreadsheets, two SaaS subscriptions and a Slack channel. Your team logs in, sees what matters, gets the job done.
Customers who feel looked after
A client portal where customers see live job status, approve work, download invoices and message you. No more 'where are we up to?' emails.
Workflows wired into the UI
Form submissions, approvals and button clicks fire AI workflows behind the scenes. The app is the cockpit; automation is the engine.
What you get
Included in every engagement
- Paid discovery sprint that locks scope, timeline and fixed fee
- Built on TanStack Start, React 19, Postgres — modern, fast, hand-off ready
- Auth, role-based access and row-level security from day one
- Pairs natively with AI workflows (Make or Zapier, OpenAI, Anthropic, custom code)
- 30 days post-launch support; optional ongoing care plan
- 100% code, design and data ownership — no vendor lock-in
Who it's for
UK SMEs and founder-led teams who have outgrown spreadsheets, off-the-shelf SaaS or a clipboard process. If a member of your team would log into this app every day — or your customers would expect a portal — this is the right service. For background automations without a UI, see AI Workflow Automation instead.
FAQ
Frequently asked questions
What counts as a 'custom web app'?
Any bespoke browser-based software that your team or your customers log into. Internal admin dashboards, client portals, quoting and booking apps, intake forms with real logic behind them, and lightweight SaaS products all qualify. If you can describe a screen people use and a thing they need to do on it, we can probably build it.
How is this different from AI workflow automation?
An AI workflow runs in the background — triggered by an event, no human watching. A custom web app is the cockpit people log into. Most real builds combine the two: the app is the interface, the workflow is the engine running behind it. We deliver both as a single fixed-fee project.
How long does a custom app take to build?
Four to ten weeks once scope is locked in. A focused internal dashboard or quoting tool sits at the lower end. A client portal with auth, roles and integrations is six to ten weeks. We always run a paid discovery sprint (£500–£1,500) first so you have a fixed fee and timeline before committing to the build.
What's the cost range?
Focused internal tools and simple quoting apps from £6,000. Client portals with auth and integrations £10,000–£18,000. Lightweight SaaS MVPs £15,000–£25,000. Every project is fixed-fee with the price agreed in writing.
Will I own the code?
Yes — 100%. Source code, designs, database and hosting accounts. The stack is TanStack Start, React, Postgres on the edge — any competent developer can pick it up if you ever want to move on.
Ready to see the numbers for your business?
30-minute discovery call, no obligation. Walk away with a clear, fixed-fee plan.