Rebuilding a B2B SaaS product's billing and permissions layer
A multi-tenant billing and role-permissions overhaul for a growing SaaS product that had outgrown its original single-tenant design.
The challenge
The product was originally built for one account per customer. As larger customers signed up wanting multiple teams and seat-based billing, the existing data model couldn't represent that without risky workarounds.
The approach
A multi-tenant data model with organization-level roles and seat-based billing, migrated in stages behind feature flags so existing customers were never disrupted mid-migration.
How we’d run this project
Audited the existing single-tenant schema and mapped every place it assumed one account per customer
Designed the multi-tenant model and a migration path that could run gradually, account by account
Built seat-based billing on top of the new model once the tenant structure was stable
Migrated existing customers in batches, monitoring for billing discrepancies at each stage
Features delivered
- Organization and team hierarchy with role-based permissions
- Seat-based billing with prorated upgrades and downgrades
- Zero-downtime migration path from the legacy single-tenant schema
- Admin dashboard for usage and billing visibility
Technology stack
Outcome
The product could sell to multi-team customers without the custom one-off contracts the sales team previously had to negotiate around the platform's limitations.