Software as a Service (SaaS) lets customers use your software in the browser for a subscription. Building one involves more than the core features.
Core building blocks
- Authentication: sign-up, login, password reset, SSO (Google, Microsoft) and 2FA
- Organisations and roles: companies with multiple users and permissions
- Multi-tenancy: data of each customer strictly separated
- Subscription billing: plans, trials, upgrades, invoices, VAT
- Admin back office: customer management, support tools, analytics
- Onboarding: guided first steps so new users see value quickly
Multi-tenancy options
| Model | Description | Good for |
|---|---|---|
| Shared database, tenant ID | All customers in one database | Most SaaS products |
| Schema per tenant | Separate schema per customer | Stronger separation |
| Database per tenant | Fully separate databases | Enterprise or regulated customers |
Billing
Tools like Stripe Billing handle subscriptions, proration, failed payments and invoices. For European customers you need correct VAT handling, including reverse charge for B2B.
Security and compliance
Encryption, audit logs, backups, role-based access and GDPR features (data export, deletion). Enterprise customers often ask for security documentation and data processing agreements – prepare them early.
Scalability
Start with a clean, modular architecture rather than complex microservices. Cloud hosting with managed databases and automated deployments lets you scale when customers arrive.
Launch strategy
- Validate with interviews and a clickable prototype.
- Build an MVP with the core workflow and simple billing.
- Onboard early customers personally and collect feedback.
- Iterate on activation, retention and pricing.
- Add integrations and self-service growth features later.
Key metrics
MRR, churn, activation rate, customer acquisition cost and lifetime value guide decisions after launch.
We build SaaS platforms from MVP to scale, including billing, admin tools and hosting in the EU.