● SaaS product development

SaaS platforms built to survive their own growth

Most SaaS products are not killed by a missing feature. They are killed by an early architecture decision that becomes unfixable around the two hundredth customer. We build multi-tenant products with the tenancy model, billing, and permissions handled properly from the first release.

50+Products shipped
5.0Clutch rating
8+Industries served
10+Industry awards
What actually goes wrong

The three decisions that decide whether your SaaS scales

A SaaS product is not a web app with a login screen. The difference is that many separate customers occupy the same system at the same time, and each one has to be completely certain that they cannot see anyone else. That single requirement reaches into the database, the authentication layer, the billing logic, the background jobs, and the support tooling. Get it right at the start and it is invisible. Get it wrong and you find out through the worst possible channel, which is a customer seeing another customer's data.

The first decision is the tenancy model: how one customer's records are kept apart from another's. The tempting shortcut is to add a customer ID column to every table and filter on it in application code. That works until the day someone writes a query that forgets the filter, and there is no safety net beneath it. We push the rule down into the database with row-level security, so isolation holds even when the application layer has a bug. It costs a little more in week two and saves the company in year two.

The second is billing, which teams consistently underestimate because the happy path is easy. Taking a first payment is a weekend of work. What takes real engineering is everything after: upgrades and downgrades mid-cycle, proration, failed payments and dunning, refunds, trials that convert, annual plans alongside monthly, and a payment webhook arriving twice for the same event without charging the customer twice. Billing bugs are the most expensive kind, because they are simultaneously a revenue problem and a trust problem.

The third is scope discipline, which is not really technical. An MVP is not a cheap version of the full product; it is the smallest thing that lets real users do the core job end to end, so you learn whether they want it. The failure mode we see most often is a founder who spends nine months and a full budget building version one in private, launches, and discovers the thing customers actually wanted was two features they never prioritized. We would rather put something narrow in front of paying users in three months and be wrong cheaply.

Tenancy, billing, and permissions are cheap to decide in week one and brutally expensive to change once you have paying customers relying on all three.

Tenant ATenant BTenant COne applicationshared code pathROW-LEVEL SECURITYPostgreSQLrows tagged by tenantTenant ATenant BTenant Ca query that forgets its filter

Isolation enforced by the database rather than by application code. A query that forgets its filter is stopped by the policy instead of quietly returning another customer's rows.

What we build

What we build into a SaaS product

The parts every serious subscription product needs, most of which never appear on a feature roadmap because customers assume they already exist.

Multi-tenant foundations

Tenancy modeled properly from the first commit, with isolation enforced in the database rather than trusted to application code. Plus per-tenant settings, roles, and invitations.

Subscription billing

Plans, trials, upgrades and downgrades with proration, dunning for failed cards, refunds, and annual pricing. Built against Stripe with webhooks that are safe to receive twice.

Auth and permissions

Sign-up, email verification, password reset, sessions, team invitations, and role-based access. Passwordless and single sign-on where your buyers expect it.

Admin and support tooling

The internal console you will need on day two: impersonation for debugging, subscription overrides, refunds, and usage visibility per account.

Scope of a build

What ships with a SaaS engagement

A launchable product, not a demo. The list below is roughly what separates something you can charge for from something you can only show.

Product

  • The core application, web first and responsive
  • Onboarding and sign-up flow built for conversion
  • Subscription billing with plans, trials, and proration
  • Team accounts, invitations, and role-based permissions
  • Transactional email on your own sending domain
  • In-app analytics so you can see what is actually used

Platform

  • Multi-tenant data model with database-enforced isolation
  • Authentication, sessions, and password recovery
  • Admin console with impersonation and billing overrides
  • Background jobs, queues, and scheduled work
  • Rate limiting and abuse protection on public endpoints
  • Structured logging, monitoring, and error alerting

Launch readiness

  • Marketing site and pricing page that search engines can read
  • Legal surface: terms, privacy policy, and cookie handling
  • Automated backups with a restore that has been tested
  • Security review before the first customer signs up
  • Deployment pipeline your team can run without us
  • Full source code and infrastructure ownership from day one
From idea to paying customers

How a SaaS engagement runs

Structured to get something in front of real users early, then to keep shipping once the feedback starts arriving.

Product and market shaping

We pressure-test the idea: who exactly pays, what job the product does for them, and what the smallest version of that job looks like. Founders regularly leave this session with a smaller version one than they arrived with.

Free consultation

Architecture and pricing model

Tenancy model, permission structure, and billing design decided together, because pricing shapes the data model more than most teams expect. Per-seat, per-usage, and flat plans are not the same system underneath.

1 to 2 weeks

MVP build

The core loop, built end to end and genuinely usable: sign up, do the main job, pay. Short milestones with a staging environment you can open at any point and try yourself.

8 to 16 weeks

Launch and first customers

Production deployment, billing switched live, monitoring in place, and the support tooling you need the first time a customer reports something strange at 9pm.

Go-live

Iterate on real usage

Now the useful work starts. We build against what users actually do rather than what the roadmap assumed, and most clients keep a continuing arrangement for exactly this phase.

Ongoing
Why Appluex

How we work on SaaS specifically

We have run these, not just built them

We operate our own multi-tenant products on the same stack we recommend, including the billing. Advice about dunning and webhook idempotency is different when you have been on the receiving end of getting it wrong.

Narrow first release, on purpose

We push hard to cut version one down to the smallest thing real users can complete the core job with. Not to save budget, but because the fastest way to learn what to build second is to ship something first.

Built for the team after us

Many founders eventually hire in-house engineers. We write the codebase, documentation, and pipeline for that handover, because a product your own team cannot take over is a liability regardless of how well it runs.

Architecture

What we build SaaS on

Chosen for products that need to still be maintainable at customer two thousand, and hireable-for if you build an in-house team later.

Product layer

Next.js
Server-rendered React, so your marketing pages and pricing page are indexable by search engines and your app is fast on first load.
TypeScript
Types end to end. On a codebase that will be edited by people who did not write it, this is the cheapest quality investment available.
React Native or Flutter
When the product needs a mobile companion, one codebase across both stores rather than two native teams.
Design system
A component library from the start, so the tenth screen takes a fraction of the time the first one did.

Tenancy and data

PostgreSQL
The system of record. Relational and transactional, which is what subscription and usage data need to be.
Row-level security
Tenant isolation enforced by the database, so a forgotten filter in application code cannot expose one customer to another.
Prisma
A typed data layer with real migrations, so schema changes are reviewable and reversible rather than improvised.
Background queues
Email, exports, billing reconciliation, and scheduled work kept off the request path so the app stays responsive.

Commerce and operations

Stripe
Subscriptions, proration, and dunning, with webhook handling built to be idempotent because payment events do arrive more than once.
Transactional email
Sending on your own authenticated domain with SPF, DKIM, and DMARC configured, so password resets reach the inbox instead of spam.
AWS
Hosting, storage, and email infrastructure, sized to your actual load rather than a hypothetical launch spike.
Monitoring
Error tracking and uptime alerting from day one. You should never learn about an outage from a customer.
Ways to start

How founders usually begin with us

Almost nobody should commit a full platform budget before seeing how a team works. These are the entry points we recommend, in order of commitment.

Product and technical shaping

Idea stage, or a rescoped version one

A short paid engagement producing a specified MVP, an architecture, a pricing-aware data model, and a costed build plan. Yours to take anywhere, including to another firm.

Often the highest-value few weeks of the whole project.

MVP build

Ready to get to market

A fixed-scope first release covering the core loop end to end, including billing and tenancy done properly. Typically 8 to 16 weeks in visible milestones.

The most common starting point for a new product.

Ongoing product team

Live, with users and a roadmap

A continuing arrangement covering new features, maintenance, infrastructure, and support. Effectively a product team without the hiring cycle.

Where most SaaS clients end up after launch.

Every engagement starts with a free consultation and a fixed written estimate. If we think your idea is better served by an existing product than a custom build, we will tell you that on the first call.

Technologies we build with

See the full stack, and what each part is for →

FAQ

SaaS development. FAQ

How much does it cost to build a SaaS product?

A genuine MVP with the core loop, authentication, multi-tenancy, and subscription billing done properly is a meaningfully different investment from a full platform, and scope is what drives the number. After a free consultation we provide a fixed written estimate tied to a defined scope. Be cautious of any quote given before the tenancy and billing model has been discussed, because those two decisions move the effort more than the feature list does.

How long does it take to launch a SaaS MVP?

Typically 8 to 16 weeks for a first release that real users can sign up for, use, and pay for. The range depends mostly on how many user types the product has and how complex the billing model is. A single-role product on flat monthly pricing is much faster than a two-sided marketplace with usage-based billing and payouts.

What is multi-tenancy, and why does it matter so much?

Multi-tenancy is how one system serves many separate customers while keeping each one's data completely isolated. It matters because it is the single hardest thing to change later. Retrofitting proper isolation onto a product that already has paying customers means touching every query, every background job, and every report, all while the system is live. We enforce isolation at the database level with row-level security so that a bug in application code cannot leak data across tenants.

Can you integrate Stripe and handle subscriptions?

Yes, and we build the parts that are easy to overlook. Taking a first payment is straightforward. Handling mid-cycle upgrades with proration, failed-payment dunning, refunds, trial conversion, annual alongside monthly plans, and webhooks that may deliver the same event twice is where the real work is. We build the webhook layer to be idempotent, so a duplicate delivery never results in a duplicate charge.

Do we own the code and the infrastructure?

Yes, from day one. The repository, the infrastructure configuration, the Stripe account, the domain, and the data are all yours. If you hire an in-house team later, they inherit a documented codebase and a deployment pipeline they can run without us. We consider that a normal and healthy outcome, not a loss.

Can you take over an existing SaaS product?

Often, yes. We start with a paid technical assessment: reading the codebase, reviewing the data model and tenancy approach, checking the security posture, and reporting honestly on what is solid and what is a liability. Sometimes the answer is that continuing the existing codebase is the right move, and sometimes it is that a specific subsystem needs replacing first. You get that assessment as a document either way.

Should we build mobile apps as well as web?

Usually not for version one. Most B2B SaaS products are used at a desk, and shipping web first gets you to paying customers and real feedback faster. Mobile earns its place when the core job genuinely happens away from a computer, which is the case for field work, logistics, and consumer products. When that is true we build with Flutter or React Native so both stores come from one codebase.

What ongoing costs should we expect after launch?

Three separate categories, and they are worth budgeting separately. Infrastructure and third-party services scale with usage and typically start modestly. Maintenance covers dependency updates, security patches, and platform changes, which is unavoidable ongoing work. New feature development is discretionary and driven by your roadmap. We break these out explicitly rather than presenting one blended monthly figure.

Do you work with founders outside Miami?

Yes. We are based in Miami and work with founders across the United States, Canada, and Europe through a fully remote, milestone-based process. Product work in particular runs well remotely, because progress is demonstrated in working software you can open and use rather than in status reports.

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Based inMiami, Florida · USA