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Software Engineering

SaaS Development

SaaS is a product you operate, not a project you finish. We build the multi-tenant foundation, the billing and the auth, then run it in production alongside you.

Overview

A SaaS product is different from other software in a way that is easy to underestimate at the start and expensive to discover later: it serves many customers from one running system, it charges them on a recurring basis, and it never really stops. The interesting engineering is not the feature you demo on day one — it is multi-tenancy, subscription billing, organisation-and-role authentication, per-tenant configuration, and the operational machinery that keeps it all up while paying customers depend on it. That surrounding system is what we build.

Two decisions made in the first fortnight shape everything after: how tenants share (or do not share) data, and how billing maps onto plans, usage and entitlements. Both are painful to retrofit. A tenancy model chosen for a ten-customer launch can become the thing blocking your hundredth customer; a billing integration bolted on late tends to leak revenue and confuse support for years. We treat these as architecture, decided and written down before the product is built around them, because they are the choices you cannot cheaply reverse.

We are candid about what this commits you to. A SaaS product is a long-term operational relationship, not a one-off delivery — someone is on call, someone watches the error rate, someone handles the failed renewal at 2am. That is why we build and operate: the same senior engineers who design the tenancy model also run it in production, so the people who understand the system are the people carrying the pager. If you want a build you can throw over a wall, we are the wrong firm.

Who it’s for — Teams building a multi-tenant product that customers pay for on a subscription — whether launching the first version or scaling one whose foundations are starting to strain.

What you get

  • A multi-tenancy model chosen deliberately — shared, isolated or a hybrid — with the trade-offs written down and defended
  • Subscription billing wired to Stripe: plans, trials, usage metering, proration, dunning and the entitlement checks that gate features
  • Authentication with organisations, roles and invitations — the team-and-permissions model real customers expect
  • Per-tenant configuration and feature flags, so you can vary behaviour by customer or plan without forking the code
  • Self-service onboarding that turns a sign-up into a working, provisioned tenant without a human in the loop
  • An admin surface and product analytics — the internal tooling you need to support, debug and understand customers
  • Observability, alerting and runbooks shipped with the product, plus the on-call setup to actually operate it

What SaaS Development does for you

  • Decisions you will not have to unwind

    The tenancy and billing choices that are near-impossible to change under load are made deliberately at the start, with their trade-offs documented — not defaulted into and regretted at scale.

  • Self-service that scales with sales

    Sign-up provisions a working tenant without a human, so adding the hundredth customer costs the same as adding the tenth. Onboarding stops being the bottleneck on growth.

  • One team that builds and runs it

    The engineers who designed the system operate it, so an incident is diagnosed by people who understand the architecture rather than triaged by a support tier reading a wiki.

Why teams choose us for SaaS Development

  • We operate what we build — the tenancy model, the billing and the on-call are all ours, so no one gets to design a problem and hand you the pager.
  • Senior engineers only. Multi-tenancy and billing are where juniors quietly introduce the bugs that surface as a cross-tenant leak or a month of mischarged invoices.
  • We are blunt about the operational commitment. SaaS is a system that runs continuously, and we will tell you what running it actually costs before you sign up to it.
  • Everything is built in your accounts — your Stripe, your cloud, your repositories — with no proprietary layer you must keep paying us to use.

What SaaS Development includes

The concrete pieces of work this covers — scoped to what your problem actually needs.

  • Multi-tenancy architecture

    Shared-schema with a tenant key, schema-per-tenant, or full database isolation — chosen against your data-sensitivity, scale and per-customer requirements, with tenant context enforced at the data layer rather than trusted at the edges.

  • Subscription billing and metering

    Stripe integration for plans, trials, proration, upgrades and downgrades, plus usage metering and the dunning flows that recover failed payments instead of silently losing the customer.

  • Organisations, roles and auth

    Authentication built around teams: organisations, member invitations, role-based permissions, SSO where enterprise customers require it, and a session model that keeps tenant boundaries intact.

  • Per-tenant config and feature flags

    Behaviour, limits and features that vary by customer or plan without forking the codebase — the mechanism that lets sales promise a variation and engineering deliver it as configuration.

  • Self-service onboarding and admin

    Sign-up that provisions and configures a tenant automatically, plus the internal admin surface your team needs to impersonate, support and debug customers safely.

  • Observability and operations

    Logs, metrics, traces, alerting and runbooks shipped with the product, plus the on-call and incident process that turns "the site is down" into a bounded, understood event.

Where it fits

  • A first product to market

    A founding team with a validated idea and no in-house platform engineering. We build the MVP with real multi-tenancy and billing from the start, so the first paying customers do not sit on a foundation that has to be replaced at customer fifty.

  • Single-tenant to multi-tenant

    A working application built for one customer, or as an internal tool, that now needs to serve many. We retrofit tenancy, roles and isolation carefully — the highest-risk kind of SaaS work, because it means separating data that was never designed to be separated.

  • Fixing the billing

    A product with customers but a billing setup held together by manual invoices, missed usage and no dunning. We wire subscriptions, metering and entitlements together so revenue reconciles and support stops fielding billing confusion.

  • Scaling a strained product

    A SaaS that found traction and is now buckling — noisy-neighbour tenants, slow admin tooling, no observability. We stabilise operations and harden the parts that tenant count and traffic actually stress.

How we approach SaaS Development

We start from the two decisions that are cheap to make and costly to unwind: the tenancy model and the billing model. Before any product code, we settle how tenant data is separated and how plans, usage and entitlements are represented, and we write those choices down with their reasoning. Getting them right is worth more than any single feature, because getting them wrong means a migration under load later.

From there we build in short, reviewable cycles toward a real MVP — not a prototype, but a product with a paying tenant, working billing and enough operational instrumentation to run it. Then we scale deliberately as customers arrive, hardening the parts that traffic and tenant count actually stress, rather than pre-building for a scale you have not reached.

How we deliver

We open with the decisions that are expensive to reverse. In the first phase we settle the tenancy model, the billing and entitlement model, and the authentication and organisation structure, and we write them down with the reasoning — because these are the choices that a later team either thanks you for or curses you for. This is deliberately front-loaded work; it is cheaper to argue about the tenancy model in a document than to migrate it under production load.

Then we build toward a real MVP in short cycles you can review against working software. A real MVP here means a product that can take a paying tenant end to end: sign-up provisions a tenant, billing charges them, roles gate what their team can do, and enough instrumentation exists to run it. We would rather ship a narrow product that genuinely works for one plan than a broad one that works in a demo.

After launch the work does not stop, and we are explicit about that. We operate the product with you — watching the error budget, handling failed renewals, tuning the parts that real tenants stress — and scale features and capacity as customers arrive. Building and operating are the same engagement, because the feedback from running it is what tells us what to build next.

The multi-tenancy model

The central architectural decision in any SaaS is how tenants share the system, and it sits on a spectrum. At one end, a shared schema where every row carries a tenant identifier: cheapest to run, simplest to operate, and the default for most products — but it puts the entire burden of separation on application code that must never forget the tenant filter. In the middle, a schema or database per tenant: stronger isolation, easier per-customer backup and residency, but more moving parts to migrate and operate. At the far end, fully isolated infrastructure per tenant: the answer for a handful of large, sensitive customers, and ruinous overhead for a thousand small ones.

There is rarely a universally correct choice — there is a choice correct for your customers, your data sensitivity and your scale. A consumer product with many small tenants and a regulated product with a few large ones want different models, and a product may sensibly run a hybrid: shared for the long tail, isolated for the enterprise accounts that demand it. What matters is deciding on purpose and enforcing it where it cannot be bypassed — tenant scoping applied at the data-access layer, not sprinkled through queries where one forgotten clause becomes a leak.

We stress the same warning every time: this is the decision most painful to change later. Migrating a live product from one tenancy model to another means moving customer data while customers are using it, and it is among the riskiest work in this field. That is precisely why we spend real time on it up front, size it for where the product is heading rather than only where it launches, and write down the reasoning so the choice is defensible when the context has been forgotten.

Tenant data isolation

In a multi-tenant system, one class of bug outranks all others: a cross-tenant data leak. One customer seeing another customer’s data is not a normal bug you patch and move past — it is a breach, a set of disclosure obligations, and the kind of trust failure that ends contracts. Every isolation decision in a SaaS is made in the shadow of that outcome, and we design accordingly.

So isolation is enforced where it cannot be forgotten rather than trusted to discipline. Tenant context is bound at the data-access boundary so a query without a tenant scope fails rather than silently returns everything; where the database supports it, row-level policies enforce separation beneath the application so a coding mistake cannot bypass them. Object storage, caches, background jobs and search indexes are all scoped too — the leak people miss is rarely the main database; it is the cache key without a tenant prefix or the queue worker that processed the wrong tenant’s payload.

Around that, the ordinary discipline still applies and is not optional: least-privilege access, secrets kept out of code, dependency and configuration scanning in the delivery pipeline, and audit logging of who touched which tenant’s data — including your own staff using admin impersonation, which is a common and under-controlled path to a leak. We also test isolation directly, with cases that deliberately attempt cross-tenant access, because the only way to trust a boundary is to try to cross it.

Signs it’s time

  • You are launching a product that many customers will use from one system, and you want the tenancy and billing foundations right the first time
  • Billing is a spreadsheet, manual invoices or a half-integrated Stripe setup, and revenue is leaking through the gaps
  • Every new customer needs a human to provision them, and onboarding does not scale with sales
  • You started single-tenant to move fast and now need multi-tenancy, roles and per-customer configuration retrofitted

Build then operate

Our method rejects the idea that a SaaS is finished at launch. The product goes live as a real MVP, and then the engagement continues into operation — because a subscription business is a promise to keep the service running, and the promise is only as good as whoever is holding the pager. We hold it, alongside your team, with the people who built the system.

That shapes how we build. Because we know we will operate it, we instrument it properly the first time, write the runbooks as we go, and design features to be debuggable in production rather than only demonstrable in review. The operational feedback loop — what breaks, what tenants actually do, where the cost sits — is the most reliable guide to what the product needs next, and we would lose it by handing the system off.

Technologies we build it with

Chosen per problem, not per fashion — this is the stack we most often reach for on this work.

How we deliver

  1. 01

    Discover

    We map the system, the constraints and the business it serves — including the parts nobody documented.

    Architecture brief

  2. 02

    Architect

    Decisions get made, written down and defended before a line of production code exists.

    Decision records

  3. 03

    Build

    Short cycles against working software. You see progress in the product, not in a status deck.

    Shipping increments

  4. 04

    Operate

    Monitoring, incident response and iteration. The system is alive, so the engagement is too.

    Runbooks & SLOs

What changes

  • Foundations that scale

    A tenancy and billing model chosen for where the product is going, not just where it launches — so growth does not force a rewrite.

  • Revenue that reconciles

    Subscriptions, usage and entitlements wired end to end, so what customers can do matches what they are billed for.

  • A product that stays up

    Observability, alerting and on-call in place from launch, so problems are caught by you before they are reported by customers.

Industries we serve

Domain knowledge changes what gets built. A few of the sectors we know before the first meeting.

How pricing works

  • The dominant cost driver is scope at launch: how many plans, whether billing is flat-rate or usage-metered, whether enterprise features like SSO and per-tenant isolation are needed on day one, and how much admin and analytics tooling the first version requires.
  • A single-tenant-to-multi-tenant retrofit costs more than a greenfield build for the same feature set, because separating data that was never designed to be separated is careful, high-risk work — and the risk is priced in.
  • Operating the product is a distinct, ongoing commitment from building it. On-call cover, incident response, dependency upkeep and the scaling work that follows customer growth are continuous, and we scope them as an operational engagement rather than folding them invisibly into a build price.
  • We do not quote a fixed figure without understanding the tenancy model, the billing complexity and the operational expectations, because those three things — far more than feature count — determine the real cost.

Typical timeline

  1. 01

    Foundations

    Tenancy, billing and auth models decided, documented and defended. The short, expensive phase that de-risks everything after it.

  2. 02

    MVP build

    A product that takes a paying tenant end to end — provisioning, subscriptions, roles and enough instrumentation to run it — shipped in reviewable cycles.

  3. 03

    Launch and harden

    First real tenants onboarded, observability and on-call live, and the parts that actual traffic stresses tuned rather than guessed at.

  4. 04

    Operate and scale

    The ongoing phase: running the product, recovering failed payments, adding features from real usage, and scaling capacity as customers arrive.

Why teams choose us for SaaS Development

  • We carry the pager

    The engineers who design your tenancy and billing also operate them in production. No one gets to make an operational problem someone else has to live with.

  • Senior on the risky parts

    Multi-tenancy and billing are unforgiving. We put senior engineers on exactly the code where a small mistake becomes a cross-tenant leak or a month of wrong invoices.

  • Honest about the commitment

    We will tell you before you start that a SaaS is a long-term operational relationship, and what that costs to run — not sell you a build and vanish at launch.

  • Built in your accounts

    Your Stripe, your cloud, your code. You own the product outright, and nothing about operating it is locked behind a layer only we can touch.

How to engage us

Three ways to work with us on this — chosen to fit the problem, not our margin.

Related services

Part of Custom Software Development. Other work we do alongside this.

Common questions

Should we start with a shared database or isolate each tenant?

For most products, a shared schema with a tenant identifier is the right start — it is the cheapest to run and simplest to operate. Full isolation is warranted when you have a few large or highly sensitive customers, or data-residency requirements that shared infrastructure cannot meet. The honest answer depends on your customers and data sensitivity, and it is the first thing we settle, because it is the hardest to change later. Many products end up hybrid: shared for the long tail, isolated for the enterprise accounts that demand it.

We built single-tenant to move fast. How hard is it to add multi-tenancy now?

Harder than building it multi-tenant from the start, and it is the highest-risk work in this field, because you are separating data that was never designed to be separated while customers are using it. It is entirely doable — we do it — but it is careful, methodical work rather than a quick refactor, and the cost reflects the risk. The one thing that makes it worse is delay: every month of new single-tenant code is more to untangle, so if you know multi-tenancy is coming, the time to plan the migration is now.

Why build billing properly instead of just adding Stripe Checkout later?

Because billing is not a payment button — it is plans, trials, proration on upgrades and downgrades, usage metering, failed-payment recovery, and the entitlement checks that decide what a customer can actually do. A half-integrated setup leaks revenue quietly and confuses support loudly, and mapping it onto a product retrospectively is painful. Getting the plan-and-entitlement model right early means what a customer is billed for and what they can do stay in sync, which is the thing that breaks first when billing is an afterthought.

What actually prevents one customer from seeing another’s data?

Enforcement at the data layer rather than trust in application discipline. Tenant context is bound so that a query without a tenant scope fails instead of returning everything, and where the database supports it, row-level policies enforce separation beneath the application so a coding mistake cannot bypass them. It extends past the main database to caches, object storage, background jobs and search indexes — the places a leak usually hides. And we test it adversarially, with cases that deliberately try to reach across tenants, because a boundary you have not tried to cross is not one you can trust.

Do you just build it, or do you run it too?

We do both, on purpose. A SaaS is a product you operate continuously — someone watches the error rate, handles the renewal that failed overnight, and answers the pager. We build the product and then operate it alongside your team, with the same senior engineers throughout, so incidents are handled by people who understand the architecture. If you want only a build to run entirely yourself we can hand over cleanly with runbooks and training, but we will be honest first about what operating it will take.

Let’s talk about SaaS Development.

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