A product you can sell,on a platform you can run.
Multi-tenant cloud products built to be sold, scaled and operated, whether you are launching a first version or hardening one that already has customers.
A SaaS product is not an internal application with a login page. Every customer runs on the same code, expects it to be up the moment they sign in, and pays you every month on the assumption that it will be. Tenant isolation, billing, onboarding and releases are not features you add once the product works; they are the product.
Experus builds multi-tenant products on Kotlin or Java with Spring Boot, PostgreSQL and React, packaged in Docker and run on Kubernetes where the scale justifies it and on something simpler where it does not. Every commit is tested before it ships, the release pipeline makes a weekly release routine rather than an event, and monitoring tells you about a problem before your customers do. If you already have a product with paying customers, the same practices are applied to what exists, without a rewrite.
Everything lives in your name from the first day: repositories, cloud accounts, domain, payment provider. You own the product. Experus designs it, builds it and runs it with you, and stays on as the platform matures.
When this is the right fit
- You have real demand for a product idea and need a first version paying customers can use, not a prototype to demo.
- Your product was built quickly by people who have since moved on, and nobody can change it without breaking something.
- You sell a service today, and want to turn the repeatable part of it into a subscription product your customers use themselves.
- Prospects ask about security, data separation and uptime, and you need answers backed by how the platform is built.
- An internal tool has grown into something other companies want, and it needs tenancy, billing and onboarding before you sell it.
What you get
A written design before the build
The tenancy model (shared schema or schema per tenant, and why), authentication and roles, data model, deployment shape and risks, with an estimate that states its assumptions. Argue with the drawing before it becomes expensive.
A multi-tenant backend
Kotlin or Java on Spring Boot, with each customer's data strictly separated, enforced in the data layer and tested. PostgreSQL schema changes under version control, single sign-on where customers require it, and a documented API.
A product front-end your customers can onboard themselves
React and TypeScript from the same typed contract as the API, so a change to a plan or role reaches every screen. Self-service sign-up, invitations and account settings, plus the admin views your team needs.
Subscription and billing built into the product
Plans, trials, metering and invoicing wired into the domain, not bolted on, with the payment provider you choose. Background jobs that survive restarts, retries and Monday-morning traffic.
A release pipeline and a platform that stays up
CI/CD that tests and scans every commit, zero-downtime deployments with a rehearsed rollback, and monitoring, backups and restore drills in place before the first customer signs in. Handed over with a plain-language runbook.
How it works
Understand
First conversations cover who pays, for what, and what must be true at launch. A written scope follows before any code.
Shape
A written design for tenancy, identity, billing, data and deployment, with named risks. For an existing product: an assessment and hardening plan.
Build
The first increment is one tenant signing up, paying and using one feature end to end. Every later increment ends with a demo.
Run and evolve
The platform goes live with monitoring, backups and rollback in place. Afterwards Experus stays as your retained product-engineering partner.
The stack behind it
Kotlin & Java
Spring Boot
PostgreSQL
React & TypeScript
Docker & Kubernetes
CI/CD
Monitoring & alerting
Hetzner, AWS, Azure & DigitalOcean
Typical engagement
Build and launch a first production version to paying customers, delivered as a design phase followed by milestone-based increments, then act as your retained product-engineering partner as the platform matures. The retained agreement is monthly, with a response window agreed in the contract and a standing improvement backlog.
Questions you might have
How is a SaaS build priced?
The design phase is quoted separately at a fixed price and ends in a written design you keep regardless of what happens next. The build is delivered in milestones, each with its own scoped estimate and its assumptions written down, so you always know what the next increment costs before it starts. After launch, operations and further development run under a monthly retained agreement. Milestones are billed per day worked against their estimate.
Who owns the code, the data and the infrastructure?
You do. The code lives in your repositories from the first commit; intellectual property in the delivered work transfers to you on payment. Cloud accounts, domain, payment provider and every credential are created in your name, and the documentation is written so that any engineer with Spring and PostgreSQL experience can take over.
What happens if Experus is unavailable?
That risk exists with any partner, and it is designed for rather than ignored: the infrastructure is defined as code, the tests document the behaviour and the runbook explains how to operate the platform, so another engineer can step in without archaeology. Every engagement has agreed dates in writing; if those cannot be met you are told immediately, with the choice to reschedule or to stop and pay only for what has been delivered. Work in progress lives in your repositories and your accounts from day one, so nothing is lost on a laptop. If the engineer on your project is unavailable for longer, a trusted specialist from the Experus network can step in, with your agreement.
How long until the first customers can use it?
It depends on the scope, and the honest answer comes out of the design phase, as a written estimate with its assumptions attached. What Experus can promise up front is the method: the first release is the smallest version a paying customer will use, it goes to production rather than to a staging server nobody visits, and the pipeline makes a weekly release routine rather than an event.
Have a product to launch, or one to harden?
Describe the product, where it stands today and who will pay for it. Rough is fine. You will get a considered reply from the engineer who would actually build it.