A SaaS Product That Doesn't Need Rebuilding at 10,000 Users.
From zero to launch and beyond, we engineer SaaS applications that are fast, reliable, and built for the complexity that comes with real growth.
The problem
Most SaaS Products Weren't Built to Survive Their Own Growth
A SaaS product isn't just a web app with a login screen. Without proper multi-tenant architecture, billing infrastructure, and access control baked in from the start, the first real usage spike is where things start breaking, outages, data isolation issues, and a codebase nobody wants to touch.
We've built SaaS products for founders in the US, UK, and Australia, from early-stage MVPs to full-scale platforms with complex billing, role-based access, and real-time features.
Systems shipped to production
Response time, Mon-Fri
Uptime SLA
Capabilities
End-to-End SaaS Engineering
MVP Development
Fastest path to a production-ready, investable SaaS product
Multi-Tenant Architecture
Proper data isolation, role-based access, and org-level customization
Subscription & Billing Systems
Stripe integration, usage-based pricing, trial flows, and dunning logic
Admin Dashboards
Full internal control panels to manage users, billing, and platform health
Real-Time Features
Live notifications, collaborative editing, and event-driven updates
Onboarding Flows
Activation-optimized user journeys that reduce churn from day one
Our approach
We Build SaaS the Way It Should Be Built
A SaaS product needs to handle multi-tenancy, data security, performance under concurrent load, and a business model baked into the infrastructure, not stitched on afterward.
We design your SaaS architecture around your growth trajectory, so you're not rebuilding core systems every time you hit a new scale milestone.
In practice
Built to Hold Under Real Load
Concurrent users
Uptime
Latency
A growing customer base outpacing the original architecture, with usage spikes causing daily outages, was rebuilt on a multi-tenant architecture running on a horizontally scalable Node and Postgres core, with isolated workloads and event-driven processing. See the full case study.
Read more
Guides on SaaS
How We Built a High Performance SaaS Platform for a UK Client
A real case study: how TwentyFour's SaaS platform was rebuilt to handle real growth, the architecture behind it, and the results after launch.
SaaS Development Cost: What to Budget at Each Stage
Real GBP budgets for SaaS MVP, growth, and scale stages, what team and infrastructure actually costs, and how to align spending with your funding stage.
SaaS Development: How to Build a Scalable Product in 2026
A practical guide to SaaS architecture, multi-tenancy, stack choice, and the real path from MVP to a product that scales, plus what it actually costs in the UK.
Why Devity
The Partner Your SaaS Deserves
Full-stack ownership, frontend, backend, database, and DevOps under one team
Business-aware engineering, we understand churn, activation, and retention, not just code
Scalable from day one, no shortcuts that become technical debt at 10,000 users
US, UK & Australia timezone coverage, async-friendly, meeting-ready
Post-launch support, monitoring, scaling, and iteration after go-live
GDPR-aligned
Tenant and user data is handled under strict confidentiality and GDPR-aligned practices for UK and EU clients.
Timezone overlap
Remote-first, with working hours that overlap the UK and Australian business day.
24h response
Every enquiry gets a reply within 24 hours, Monday through Friday.
Have a SaaS idea or product that needs rebuilding?
Start a ProjectOr get a free technical audit firstFAQ
Questions, Answered.
We only have an idea, not a spec. Can you still help us build it?
Yes. Most of our SaaS clients start with an idea, not a finished spec. We run a discovery phase to define scope, architecture, and success metrics before any code gets written.
How do you handle billing and subscriptions?
We integrate Stripe for subscription billing, including trial flows, usage-based pricing, and dunning logic for failed payments, built into the platform from the start, not bolted on later.
What if our user base grows much faster than expected?
We architect multi-tenant systems for scale from day one, so a growth spike does not force a rebuild. This is one of the most common reasons SaaS founders come to us after outgrowing an earlier build.
Do you support the product after launch, or just hand it over?
We offer structured post-launch support, monitoring, scaling, and iteration, so your platform keeps performing as your user base grows.