Fulminous Software designs and builds custom web applications for UK startups, SMEs and enterprises: customer portals, SaaS products, dashboards, booking systems and internal tools that replace spreadsheets and manual work. You get secure, scalable software, an itemised GBP quote and full ownership of the code.
- London-headquartered since 2019
- Two-week sprints with working demos
- NDA and full IP ownership
Web applications that do real work for your business
A web app is software that runs in the browser: users log in and get things done, whether that's booking appointments, managing orders, approving documents or tracking performance. Because it works on any device with a browser, there's nothing to install and every user is always on the latest version.
As a web app development company, we handle the whole journey: discovery, UX and UI design, front-end and back-end development, integrations, testing, cloud hosting and ongoing support, with one team accountable from start to finish.
Need a marketing website instead? See our custom web development services.
Website vs web app: what's the difference?
| Website | Web app | |
|---|---|---|
| Main purpose | Inform and generate enquiries | Let users complete tasks |
| Users | Mostly anonymous visitors | Logged-in customers, staff or partners |
| Typical features | Pages, blog, contact forms | Accounts, dashboards, workflows, payments, data |
| Built with | Often a CMS such as WordPress | Custom front end, back end and database |
| Examples | Company site, portfolio, brochure | Client portal, SaaS product, booking system |
Our web app development services
From a focused internal tool to an enterprise platform, we build web applications around your users and processes.
Custom web app development
Bespoke applications for customers, staff or partners, built around your workflows and data.
SaaS platform development
Multi-tenant products with subscriptions, user roles, onboarding and analytics.
Customer and partner portals
Secure self-service areas for accounts, documents, orders, bookings and support.
Progressive web apps (PWAs)
Installable, fast web apps with offline support, often a cost-effective alternative to separate mobile apps.
Enterprise web applications
Workflow, reporting and operations systems with single sign-on, audit trails and integrations.
AI-powered web apps
Smart search, assistants, document processing and automation built into your application.
Web app UI/UX design
User research, wireframes and prototypes tested before development begins.
API development and integration
Connecting your web app to payments, CRMs, ERPs, accounting and identity systems.
Maintenance and modernisation
Security updates, performance improvements and upgrades of ageing web applications.
Testing an idea first? Start with our MVP development services.
Examples of web apps UK businesses commission
| Web app | Example use |
|---|---|
| Client portal | An accountancy firm sharing documents, tasks and deadlines with clients |
| Booking and scheduling | A clinic group managing appointments, staff rotas and reminders |
| B2B ordering | A wholesaler offering trade pricing, reorders and live stock levels |
| Operations dashboard | A logistics company tracking jobs, drivers and deliveries |
| Learning platform | A training provider delivering courses, assessments and certificates |
| SaaS product | A startup selling subscription software to other businesses |
Our web app development process
Discovery
Goals, users, workflows, integrations and priorities agreed.
Planning
Architecture, data model, milestones and budget.
UX and UI design
Wireframes and prototypes tested with real users.
Development
Two-week sprints with working demos.
Testing
Functional, security, performance and accessibility testing.
Deployment
Automated release to secure cloud hosting.
Support
Monitoring, updates and new features.
Technologies we use
Proven, widely used technologies that are easy to maintain and hire for.
Secure, fast and accessible by design
Web apps often handle personal and business-critical data, so security, performance and accessibility are built in from the start rather than added at the end.
- Secure authentication, role-based access and single sign-on
- Encryption in transit and at rest
- Protection against common web vulnerabilities
- UK GDPR-aware data handling and retention
- Fast loading and Core Web Vitals in mind
- Accessible interfaces in line with WCAG guidance
How much does a web app cost?
Indicative UK ranges. Your quote depends on features, user roles, integrations and compliance needs.
| Project type | Typical cost | Typical timeline |
|---|---|---|
| MVP or focused internal tool | £15,000 – £40,000 | 8 – 16 weeks |
| Multi-user platform or SaaS product | £40,000 – £120,000 | 4 – 7 months |
| Complex or enterprise system | £120,000+ | 7 months or more |
Prices exclude VAT. For a fuller breakdown, see our software development cost guide.
Have a web app idea or a process to fix?
Tell us what you need. We'll suggest what to build first, the right technology and a realistic budget.
Industries we build web apps for
Retail and ecommerce
B2B ordering, marketplaces, subscriptions and stock management.
Education
Learning platforms, assessments and student portals.
Finance and professional services
Client portals, document workflows and reporting tools.
Logistics
Job tracking, fleet dashboards and delivery management.
Web applications from our portfolio
A selection of web platforms our team has designed and built.
EasyRecovery
A shared web platform for lenders and recovery agencies to track asset recovery.
View case study
BuildHubPlus
Construction project management for schedules, sites and contractors.
View case study
LawDeskCare
Case management for lawyers, covering hearings, documents and clients.
View case study
IQ Study
An e-learning platform with live classes and online courses.
View case study
FinTrack360
Accounting and invoicing software that automates bookkeeping for SMEs.
View case study
LandMart
A property marketplace connecting buyers, sellers and independent agents.
View case studyWays to work with us
Fixed price
For a clearly defined scope, with agreed cost and milestones.
Time and materials
For evolving requirements, with flexible priorities and transparent billing.
Dedicated team
Developers working on your roadmap long term, managed during UK hours.
Why choose Fulminous Software
One team, end to end
Design, development, testing, DevOps and support under one roof.
Itemised GBP quotes
Clear proposals with VAT shown separately.
Visible progress
Two-week sprints with working demos.
Technology-agnostic advice
We recommend tools for your needs, not our habits.
London-headquartered
Project management during UK business hours.
You own the code
Source code, designs and documentation handed over.
Web app development FAQs
What does a web app development company do?
A web app development company designs, builds and maintains software that runs in a web browser, such as customer portals, SaaS products, dashboards, booking systems and internal business tools. That usually covers discovery, UX and UI design, front-end and back-end development, integrations, testing, hosting and ongoing support.
How much does web app development cost in the UK?
As a guide, an MVP or focused internal tool typically costs £15,000 to £40,000, a multi-user business platform or SaaS product £40,000 to £120,000, and a complex enterprise system £120,000 or more. Cost depends on features, user roles, integrations, security and compliance requirements. We provide an itemised GBP quote after discovery.
How long does it take to build a web application?
A focused MVP or internal tool usually takes 8 to 16 weeks, a multi-user platform 4 to 7 months, and a complex enterprise system longer. We work in two-week sprints, so you see working software throughout the project.
What is the difference between a website and a web app?
A website mainly presents information, such as services, articles and contact details. A web app lets users log in and get things done, such as booking, ordering, managing data or collaborating. Many businesses have both: a marketing website and a web app for customers or staff.
Which technologies do you use to build web apps?
We commonly use React, Next.js, Angular or Vue on the front end, and Node.js, Python, .NET or PHP and Laravel on the back end, with PostgreSQL or MySQL databases and hosting on AWS, Microsoft Azure or Google Cloud. We recommend the stack based on your requirements and long-term maintenance.
Can you build a progressive web app (PWA)?
Yes. A PWA is a web app that can be installed on a phone's home screen and work offline. It can be a cost-effective alternative to separate iOS and Android apps for many business use cases.
Can my web app integrate with our existing systems?
Yes. We integrate web apps with CRMs, ERPs, accounting software, payment providers, identity providers and other third-party services using APIs, so data flows between systems without manual re-entry.
Will we own the source code?
Yes. Full ownership of the source code, designs and documentation is transferred to you, so you can host, change or extend your web app with any developer in future.
Do you provide support after launch?
Yes. We offer ongoing maintenance covering security updates, bug fixes, monitoring, performance improvements and new features.
Let's build your web app
Tell us about your users, goals and timeline. We'll come back with practical recommendations and an itemised GBP quote.
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