Multi-tenant SaaS architecture and hosting cost in Amsterdam

The verdict in three sentences

For a B2B SaaS targeting 200 business customers in 2026, a shared database with row-level isolation remains the best cost-to-risk ratio as long as no enterprise account demands physical separation. Schema per tenant adds EUR 8,000 to 12,000 in development but reassures demanding IT departments, and database per tenant only makes sense for contracts above EUR 30,000 a year. In every case hosting must stay inside the European Union, and the decision has to be made before the first line of business code, because migrating later costs two to three times more.

The three architecture models compared

A multi-tenant SaaS serves several customers (tenants) from a single application. The real question is how their data is separated. Below are 2026 orders of magnitude from mid-sized projects, for a Next.js or Node application on PostgreSQL.

The upfront premium covers tenant resolution, cross-tenant leakage tests, migration scripts and operations tooling. With a shared database, PostgreSQL Row Level Security does most of the work, provided it is tested systematically: one badly filtered query is enough to expose one customer's data to another.

EU hosting: what the options really cost

European buyers now ask about data location at the first meeting. GDPR, enterprise contract clauses and, in some sectors, sovereign cloud certifications drive the choice. Here is a 2026 estimate for 200 active tenants, about 4,000 users and 150 GB of data.

These figures include application servers, managed database, storage and backups, but not on-call support. With 200 customers paying EUR 150 a month, i.e. EUR 30,000 of monthly revenue, even database per tenant stays under 9% of revenue. The real cost hides in operations: every extra database needs monitoring and version upgrades.

The six-week timeline and the hybrid approach

A team of two senior developers and a part-time architect delivers the multi-tenant foundation in six weeks: scoping and data model (week 1), authentication and tenant resolution by subdomain (weeks 2 and 3), isolation and leakage tests (week 4), migration and backup tooling (week 5), load tests and security documentation (week 6).

The approach we recommend most often is hybrid: a shared database for most customers, with the option to move an enterprise account to its own database when it asks and pays for it. The code is written from day one so a tenant can point to a dedicated connection. This adds about EUR 3,000 to the foundation, but it avoids a rewrite the day a large group makes physical isolation a condition of signing.

Mini case study

Daan, CTO of an Amsterdam start-up selling scheduling software to accounting firms, expects 200 customers within eighteen months, including five enterprise accounts. He compares two options over three years.

Database per tenant for everyone: EUR 20,000 upfront plus EUR 2,100 a month on average, i.e. 20,000 + 75,600 = EUR 95,600.

Hybrid option: EUR 11,000 upfront, EUR 450 a month for the shared database and 5 dedicated databases at EUR 120 a month, i.e. 11,000 + 16,200 + 21,600 = EUR 48,800.

The gap reaches EUR 46,800 over three years, and the five enterprise accounts get the isolation they require. Daan also charges EUR 250 a month for the dedicated database option, which more than covers its cost.

FAQ

Is Row Level Security enough to pass an enterprise security review?

In about 70% of the questionnaires we see, yes, if you document the policies and provide automated leakage tests. Banking, healthcare and defence more often require a dedicated database.

Can we move from a shared database to schema per tenant later?

Yes, but budget EUR 15,000 to 25,000 and several weeks of feature freeze for an application already in production. Building the abstraction from day one costs about EUR 3,000.

Is hosting with a US provider in an EU region GDPR compliant?

It is generally accepted with standard contractual clauses and the EU US data framework, but some public buyers require a European host. Check your first ten prospects before choosing.

What does monthly operations cost beyond hosting?

Plan EUR 800 to 1,500 a month for maintenance and monitoring for a 200-tenant SaaS, roughly a day and a half of developer time per week.

Is six weeks realistic?

For the multi-tenant foundation alone, yes. Business features come next and usually take 8 to 16 more weeks for a sellable V1.

Let's scope your project. We define your multi-tenant architecture, the foundation budget (EUR 8,000 to 20,000) and the EU hosting that fits your customers, with a firm six-week plan. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.