Almost nobody in custom software publishes prices, which makes this one of the most frustrating things to research. So here are real 2026 ranges for a custom client portal, what moves the number, and where the money actually goes. Fixed pricing is our default, so these are the figures we work from, not a vague "it depends".
The short answer
- Lean first version: £8,000 to £25,000. A production-ready portal covering one core workflow: secure login, the main thing your clients need to do, and one integration. Real, deployable, not a prototype.
- Established portal: £25,000 to £60,000. Billing and payments, document handling, messaging, notifications, an admin side for your team, and two or three integrations.
- Platform: £60,000+. Multi-tenant architecture, complex role and permission models, reporting and analytics, several integrations, and often data migration from legacy systems.
Most first engagements we quote land in the first two bands. The trick to staying at the lower end is scope discipline, which we will come back to.
What actually drives the cost
It is rarely the number of screens. The expensive parts are the ones users never see directly:
- Integrations. Every external system the portal talks to (accounting, payments, a CRM, your operational database) adds design, build, and error-handling work. This is usually the single biggest lever.
- Permissions. "Clients see their own data" is cheap. "Account owners see their team, managers see their region, and admins see everything, with audit trails" is a real body of work.
- Real-time features. Live updates, chat, and notifications cost more than request-and-refresh screens.
- Compliance. Encryption requirements, audit logging, data-residency rules, and formal assessments add scope, and are non-negotiable in regulated sectors.
- Data migration. Moving years of records out of spreadsheets or a legacy system, cleanly and verifiably, is often underestimated.
Where the money goes
A rough breakdown of a typical build helps explain the number:
- Discovery and scoping (10 to 15%). Mapping the workflow, the edge cases, and the integrations before a line of code is written. Skipping this is how projects overrun.
- Core build (50 to 60%). Authentication, the main objects and workflows, the admin side, and the integrations.
- Testing and hardening (15 to 20%). Security, edge cases, and the unglamorous work that separates a demo from something you can put in front of clients.
- Migration, launch, and handover (10 to 15%). Moving data, going live safely, and documentation so you are not dependent on us forever.
Ongoing costs
The build is not the only number. Budget for:
- Hosting: typically £20 to £200 a month for most portals, depending on scale.
- Third-party services: payment processing fees, email delivery, and any APIs you rely on.
- Maintenance: security updates and small changes. Plan for a modest monthly retainer or a periodic budget rather than assuming zero.
Compared with per-seat SaaS pricing that grows with every client you add, a custom portal's running costs stay flat as you scale, which is a large part of why builds pay off over time.
How to keep the number down
The biggest cost control is scope, not rate. Practical ways to spend less without ending up with a toy:
- Ship the core workflow first. Build the one thing clients must be able to do, get it live, and add the rest once it is earning its keep.
- Defer the nice-to-haves. Dashboards, analytics, and automation are easier to justify once the portal is in real use.
- Reduce integrations at launch. Each one you postpone is real money saved now.
- Bring clean data. Time spent tidying your data before migration is cheaper than us cleaning it during the build.
Why fixed price
Hourly billing puts the risk of a bad estimate on you. Fixed price puts it on us, which is where it belongs. We scope the work, agree the deliverables and the number before starting, and quote any scope changes separately before they are built. You always know what you are spending and what you are getting.
If you want a real figure for your situation rather than a range, read how we build client portals or book a call. A 30-minute conversation is usually enough for us to give you a considered ballpark, and a fixed quote follows scoping.