Multi-tenant SaaS architecture for franchise networks in Berlin (2026)

The verdict in three sentences

For a SaaS serving 40 franchise networks, the best 2026 architecture is a shared database protected by Row Level Security, with the ability to move a network to a dedicated database in under a day when a large account requires it. Infrastructure overhead ranges from about 0.5 euros per outlet per month on the shared model to around 3 euros on dedicated databases, a gap that matters little next to the risk of leaking data between two competing brands. Full development runs 120,000 to 200,000 euros over 7 months as a 2026 order of magnitude in Berlin, brand customisation included.

Three isolation models, three risk profiles

A franchise network stores sensitive data: revenue per outlet, margins, franchisee contracts, loyalty programme customer data. Two competing brands on the same platform must never see each other, even if a bug slips through. The isolation choice has to be made at the start, because it shapes every query in the code.

App-level filtering alone is not acceptable for competing brands' data. With Row Level Security, each connection carries the network ID and PostgreSQL enforces the policy itself: even a badly written query only returns authorised rows.

Brand customisation without forking the code

Each network wants its logo, colours, vocabulary (store, branch, restaurant), KPIs and sometimes its own royalty rules. The right pattern stores these settings in per-tenant configuration: theme, labels, enabled modules, parameterised royalty formulas. The code stays single, and all 40 networks get each improvement on the same day.

Networks also have user layers: headquarters sees every outlet, area managers see their region, franchisees see only their store. Row Level Security handles both dimensions, network then scope, provided it is designed from day one.

Dedicated database on demand as a sales argument

Large networks, especially those backed by a group or fund, often ask for a dedicated database in their security questionnaire, and German buyers frequently add hosting in a Frankfurt region and a GDPR data processing agreement (AVV). Planning a script from the start that extracts all of a tenant's rows, loads them into a new database, checks counts and switches the connection lets you say yes in under a day, with less than an hour of night-time downtime. This option can be sold as a higher subscription tier.

Automated tests must continuously verify that a user from network A cannot read any row from network B, on every table. A targeted penetration test on isolation completes the setup before signing key accounts. For headquarters authentication, SSO with their Microsoft directory helps close deals, as explained in our article on Entra ID single sign-on for business apps.

Mini case study

Lena, founder of a Berlin software startup, targets 40 franchise networks and 2,000 outlets within 3 years, with a hypothetical subscription of 45 euros per outlet per month.

• Target revenue: 2,000 × 45 = 90,000 euros a month.
• Option 1, dedicated databases for all: 2,000 × 3 = 6,000 euros a month of infrastructure, plus running 40 databases.
• Option 2, hybrid: 1,700 outlets on the shared database at 0.6 euros and 300 on dedicated databases for 3 large networks at 3 euros, 1,020 + 900 = 1,920 euros a month.
• Gap: 4,080 euros a month, about 49,000 euros a year.

With development at 160,000 euros, the hybrid's infrastructure saving covers about 31% of the initial budget each year, while still selling maximum isolation to the 3 brands that demand it.

FAQ

Is Row Level Security safe enough for competing brands?

Yes if the database enforces it on every table, backed by automated isolation tests. Many B2B SaaS products run this way, with an overhead of 0.5 to 0.8 euros per outlet per month.

When should a customer move to a dedicated database?

When a contract requires it, when a network exceeds 15 to 20% of total load, or when it needs a specific hosting region. The move takes under a day if the tooling exists from the start.

How long until the first network is live?

A pilot network can go live in month 5, then 2 to 4 more per month. Full development fits in 7 months.

How do we handle different royalty rules per network?

Formulas (percentage of revenue, fixed fee, tiers) are parameterised in tenant configuration. That covers over 90% of franchise contracts without custom code.

Does GDPR require a database per customer?

No, it requires appropriate security and the ability to delete or export a customer's data. A shared RLS database allows both, with a per-tenant export in minutes.

Let's scope your project. We design isolation, brand customisation and the tenant migration tool, then deliver your multi-tenant SaaS in about 7 months. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.