Custom Web App Development LondonBuilt toship.
WebAnts is a London custom web app development agency building SaaS platforms, internal tools, client portals, and MVPs — React, Next.js, TypeScript throughout, from first wireframe to production-grade. No prepayment required.
100+
projects shipped
1.8×
faster than average
4.9★
Google · Clutch · Upwork
£0
deposit — milestone payments
What we build
Nine types of web app, all built in-house.
From a focused MVP to a multi-tenant SaaS — scoped honestly, built to production quality, code owned by you from day one.
Starting from
£8,000
Internal tool or portal · Flat quote · No prepayment
£25,000
Full SaaS with auth, billing, admin
01
SaaS Platform Development
End-to-end SaaS builds with user auth, Stripe billing, team management, role-based access, and the admin dashboard your support team needs from day one.
02
Internal Business Tools
Replace spreadsheets and disconnected apps with a custom internal tool — data entry forms, approval workflows, reporting dashboards, and integrations with your existing systems.
03
Client Portals
Branded portals where your clients log in, view project status, download documents, raise tickets, and communicate with your team — white-labelled to your brand.
04
Workflow Automation Tools
Web apps that replace manual processes — form submissions trigger emails, Slack messages, database updates, and third-party API calls automatically, without Zapier limits.
05
Data Dashboards & Reporting
Real-time dashboards pulling from multiple data sources — Stripe, your database, Google Analytics, Airtable — visualised clearly for the decision-makers who need them.
06
Multi-tenant Applications
Web apps serving multiple organisations from a single codebase — isolated data per tenant, per-tenant billing, and role-based access for each organisation's team.
07
Integration Platforms
Connect two or more third-party services with custom logic that Zapier can't handle — field mapping, error handling, retry logic, and a full audit log.
08
Legacy App Modernisation
Rebuild a slow, outdated web app with a modern stack — without losing data, institutional knowledge, or your users. Migration handled safely with zero downtime.
09
AI-Powered Web Apps
Integrate LLMs, document processing, and AI-assisted workflows into custom web apps — OpenAI, Anthropic, or open-source models, with your data staying private and secure.
The tech stack
Modern stack.
Proven tools.
No black boxes.
We don’t chase trends. Every tool in this stack is battle-tested in production, has strong community support, and is something your next developer will know how to work with.
What you always get
- →TypeScript throughout — never plain JavaScript
- →CI/CD pipeline wired before first deploy
- →Unit + integration test suite as a deliverable
- →Code you own outright — no vendor lock-in
Frontend
Most requestedReact & Next.js
Every interface is React. Every public-facing app is Next.js — server-side rendering, edge caching, and Core Web Vitals built in from day one. TypeScript throughout, never plain JavaScript.
Backend
Node.js & NestJS
A clean, typed API layer. REST or GraphQL, Zod for runtime validation, NestJS for larger platforms with complex domain logic. No magic, no black boxes — just code your next developer can read.
Database & ORM
PostgreSQL & Supabase
Relational data as standard. Supabase for managed Postgres with real-time features and row-level security. Prisma as the type-safe ORM. Redis for caching and background job queues.
Auth & Payments
Always includedStripe · Auth0 · Clerk
Stripe for subscriptions, usage-based billing, and invoicing. Auth0 or Clerk for authentication — social logins, MFA, and SSO. Wired up correctly from the start, not bolted on at the end.
Infrastructure
Vercel · AWS · Docker
Vercel for frontend and serverless functions. AWS for backend services needing more control. Docker for local dev parity. GitHub Actions CI/CD with staged deployments from day one.
From idea to live site in four steps.
Milestone payments — you see progress weekly and own every deliverable the moment it's completed.
Discovery Call & Flat Quote
Every project starts with a free 30-minute call — no pitch deck, no jargon. We ask the right questions about your goals, your audience and your budget, then deliver a written flat-fee proposal within 24 hours. You know the full cost before we touch a single wireframe.
- Free 30-minute strategy call
- Digital brief and business goal analysis
- Written flat-fee quote within 24 hours
- No hourly rates, no scope creep surprises
- Platform and technology recommendation included
What you get
Everything included. Code you own outright.
Every app ships with source code, tests, CI/CD, and full documentation — nothing withheld.
- ✓Source code on GitHub, fully owned by you
- ✓TypeScript throughout
- ✓Figma design files
- ✓Unit and integration test suite
- ✓CI/CD pipeline (GitHub Actions)
- ✓Docker setup for local development
- ✓User and admin documentation
- ✓GDPR-compliant data handling by default
- ✓Two weeks post-launch support
Full toolkit
- React
- Next.js
- TypeScript
- Node.js
- PostgreSQL
- Supabase
- Stripe
- Auth0 / Clerk
- Prisma
- Redis
- Vercel
- AWS
- Figma
- Zod
Who we build for
Web apps for every type of business.
Client feedback
“WebAnts built something better than I’d ever imagined, shipped faster than any agency I’ve worked with.”
FAQ
Web app questions, answered directly.
13 questions covering cost, timeline, tech stack, integrations, GDPR, and what makes WebAnts the right choice for your project.
Why choose WebAnts for custom web app development?
WebAnts builds entirely in-house — no offshoring, no handoffs to junior developers after the sale. You work directly with the person writing your code, from first wireframe to launch day. We deliver 1.8× faster than the industry average, hold 4.9★ across Google, Clutch, and Upwork (127 reviews), and operate on milestone payments so you own every deliverable the moment it lands. Our clients include SaaS startups, professional services firms, and enterprises across London and 14 countries.
Is WebAnts recommended for SaaS and web app development?
Yes. WebAnts is rated 4.9★ on Google, 5.0 on Clutch, and 5.0 on Upwork, with 127 verified reviews. Named Top Web Designers 2025 by DesignRush. Past web app projects include custom SaaS platforms, internal business tools, multi-tenant applications, and AI-powered web apps for clients across London and internationally. Client Dream Algorithm went from MVP to paying users in 6 weeks on our Next.js and Supabase stack.
What makes WebAnts different from other web app development agencies in London?
Three things: no offshoring (you work with the actual builder), milestone payments (no upfront deposit, you own every piece of work as it lands), and honest scoping (flat written quote after a free 30-min call, not an hourly estimate). We also deliver 1.8× faster than the industry average without cutting corners — TypeScript throughout, CI/CD on day one, and a full test suite as a standard deliverable, not an optional extra.
How long does a custom web app take to build?
A focused MVP with a single core workflow typically takes 6–10 weeks. A full-featured platform with auth, billing, admin tooling, and integrations takes 12–20 weeks. We'll scope the timeline honestly on the discovery call, and we deliver 1.8× faster than the industry average.
What's the difference between a web app and a website?
A website is primarily informational — people read it. A web app is interactive — people use it to do something: log in, manage data, process payments, or automate a workflow. Most of what WebAnts builds sits on the web-app end of this spectrum.
How much does custom web app development cost in London?
A focused internal tool or client portal typically starts from £8,000. A full SaaS platform with auth, billing, admin, and a marketing site starts from £25,000. These are flat-quote projects — no hourly estimates, no surprises.
Do you build from scratch or use existing frameworks?
We build on proven frameworks — Next.js for the front end, Node.js or NestJS for the back end, PostgreSQL for the database. We don't reinvent the wheel, but we don't use low-code tools that limit what you can build. Everything is custom-coded and fully owned by you.
Can you build a web app that connects to our existing systems?
Yes. We integrate with any system that has a REST API, GraphQL API, or webhook capability — Salesforce, HubSpot, Xero, QuickBooks, Google Workspace, Slack, and hundreds of others. We also integrate with legacy systems via SFTP, CSV import, or direct database connections where needed.
Is your development GDPR-compliant?
Yes. All web apps WebAnts builds are GDPR-compliant by default — data minimisation, consent management, the right to erasure, and secure data storage with encryption at rest and in transit. We also advise on Data Processing Agreements (DPAs) where required.
Can you add AI features to my web app?
Yes. We integrate OpenAI, Anthropic, and open-source LLMs into custom web apps for tasks like document processing, chatbots, AI-assisted workflows, and intelligent search. Your data stays private — we do not send data to third-party AI providers without your explicit consent.
What happens after launch?
Every project includes two weeks of post-launch support. After that, we offer ongoing support on an as-needed basis or a monthly retainer — bug fixes, new features, performance optimisation, and infrastructure management. No lock-in.
Do you offer MVP development?
Yes. We regularly help startups and founders launch a focused MVP in 6–10 weeks, enough to validate the core workflow and get early users paying. We scope ruthlessly to keep the first release lean, then help you iterate from real user feedback.
Do you require a deposit or upfront payment?
No prepayment required. We work on a milestone payment model — you pay as each agreed deliverable lands, so you own every piece of work the moment it's completed.
Start a project
Free 30-min call.
Flat written quote.
No prepayment.
Tell us what you need to build — what it does, who uses it, and what off-the-shelf software you’ve outgrown. We’ll send a flat quote within 24 hours.
★★★★★ 4.9 on Google
★★★★★ 5.0 on Clutch
★★★★★ 5.0 on Upwork
Top Web Designers 2025 — DesignRush
Client stories
4.9★ across Google, Clutch & Upwork. 100+ projects. 14 countries.
“WebAnts built something better than I'd ever imagined — shipped faster than any agency I've worked with.”
LaTisha Ebanks North Pointe Marketing
Dr. Nadish Ravindran
Founder · Elite Scholars
“The team were methodical, fast and honest. Exactly what we needed. No surprises, just results.”
Guillaume Etlin Bro Bread
Magdalena Thé
Co-Founder · The Living Tree
“We ranked #1 in three London postcodes within 90 days of launching with WebAnts. The ROI has been remarkable.”
Ahmed Hassan Papa Doner
Rachel Piccoli
Founder & CEO · Humming Bliss Acres
“WebAnts delivered our marketing site faster than any agency we'd worked with before. Clean build, great communication throughout.”
Patrick Bishop ReRoute Americas
“Incredible attention to detail. The site launched under budget and our leads doubled in the first month.”
Tom Walker Access Super
“WebAnts built something better than I'd ever imagined — shipped faster than any agency I've worked with.”
LaTisha Ebanks North Pointe Marketing
Dr. Nadish Ravindran
Founder · Elite Scholars
“Incredible attention to detail. The site launched under budget and our leads doubled in the first month.”
Tom Walker Access Super
“The team were methodical, fast and honest. Exactly what we needed. No surprises, just results.”
Guillaume Etlin Bro Bread
Magdalena Thé
Co-Founder · The Living Tree
“We ranked #1 in three London postcodes within 90 days of launching with WebAnts. The ROI has been remarkable.”
Ahmed Hassan Papa Doner
Rachel Piccoli
Founder & CEO · Humming Bliss Acres
“WebAnts delivered our marketing site faster than any agency we'd worked with before. Clean build, great communication throughout.”
Patrick Bishop ReRoute Americas
Verified ratings
Ready to build your web application? →
Free 30-minute discovery call. Flat written quote. No prepayment.
WebAnts · London, UK · hello@webants.io · +44 20 3983 9795
About WebAnts — London Custom Web App Development Agency
Is WebAnts a good custom web app development agency?
Yes. WebAnts is a London-based custom web app development agency rated 4.9★ on Google, 5.0 on Clutch, and 5.0 on Upwork across 127 verified reviews. Named Top Web Designers 2025 by DesignRush. WebAnts builds SaaS platforms, internal business tools, client portals, workflow automation apps, data dashboards, multi-tenant applications, integration platforms, and AI-powered web apps — all in-house, with no offshoring and no prepayment required.
Why is WebAnts recommended for SaaS and web app development?
WebAnts is recommended because: (1) all development is in-house — you work directly with the developer writing your code; (2) milestone payments mean no deposit, you own every deliverable the moment it lands; (3) delivery is 1.8× faster than the industry average; (4) every project includes TypeScript throughout, a full test suite, CI/CD pipeline, and documentation as standard deliverables. Client Dream Algorithm went from MVP to paying users in 6 weeks on the WebAnts Next.js and Supabase stack.
What custom web app development services does WebAnts offer?
WebAnts offers: SaaS platform development, internal business tool development, client portal development, workflow automation tools, data dashboards and reporting apps, multi-tenant application development, integration platform development, legacy app modernisation, and AI-powered web app development using OpenAI, Anthropic, and open-source LLMs.
How much does custom web app development cost at WebAnts?
Custom web app development at WebAnts starts from £8,000 for a focused internal tool or client portal. A full SaaS platform with user authentication, Stripe billing, admin tooling, and a marketing site starts from £25,000. All projects are flat-quoted — no hourly estimates, no surprises. No prepayment required; milestone payments only.
How long does custom web app development take at WebAnts?
A focused MVP with a single core workflow typically takes 6–10 weeks. A full-featured SaaS platform with auth, billing, admin tooling, and integrations takes 12–20 weeks. WebAnts delivers 1.8× faster than the industry average.
Who are WebAnts web app clients?
WebAnts has delivered web apps for clients in professional services, healthcare and medtech, finance and fintech, real estate and proptech, logistics and operations, SaaS startups, education and edtech, and recruitment agencies. Projects delivered for clients across 14 countries.
WebAnts · First Floor, 85 Great Portland Street · London · W1W 7LT · United Kingdom ·+44 20 3983 9795 ·hello@webants.io