SaaS web development is fundamentally product engineering. You are building a software product that must scale from 0 to thousands of users, handle subscription billing, manage multi-tenant data, and iterate quickly based on user feedback.
Core Features to Build
Authentication & User Management
- Sign up/login — email+password, magic link, SSO (Google, GitHub, Microsoft)
- Role-based access — admin, member, viewer, custom roles
- Team management — invite members, manage permissions, remove users
- Multi-factor auth — TOTP, SMS, passkeys for security
- Session management — device list, remote logout, session timeout
- Onboarding flow — guided setup wizard for new users
Subscription Billing
- Pricing plans — free, starter, pro, enterprise with feature gating
- Trial management — 14-day trial with upgrade prompts
- Payment processing — Stripe for cards, invoicing, tax calculation
- Usage-based billing — metered billing for API calls, storage, seats
- Plan management — upgrade, downgrade, cancel with proration
- Invoice history — downloadable invoices, payment receipts
- Dunning — failed payment recovery emails and grace periods
Multi-Tenancy
- Data isolation — each organization's data completely separated
- Workspace switching — users belong to multiple organizations
- Custom domains — white-label with customer's own domain
- Branding — per-tenant logo, colors, email templates
- Data residency — region selection for compliance (EU, US, APAC)
- Admin console — super admin view across all tenants
Product Core
- Dashboard — key metrics, recent activity, quick actions
- CRUD operations — create, read, update, delete for core entities
- Search — full-text search across user data
- Filtering & sorting — configurable views of data
- Notifications — in-app, email, and webhook notifications
- Audit log — track all user actions for compliance
- API — REST or GraphQL API for integrations
Growth Features
- Marketing site — separate from app, optimized for SEO and conversion
- Documentation — API docs, user guides, changelog
- Help center — searchable knowledge base, FAQ
- Feature flags — gradual rollout, beta testing, A/B testing
- Analytics — user engagement, feature usage, churn indicators
- Referral program — user referrals with tracking
- Integrations marketplace — connect with third-party tools
Technical Architecture
- Frontend: Next.js (marketing + app), React with TypeScript
- Backend: Node.js API, tRPC or GraphQL for type-safe APIs
- Database: PostgreSQL with row-level security for multi-tenancy
- Auth: Clerk, Auth0, or NextAuth.js for authentication
- Payments: Stripe Billing with webhooks
- Queue: BullMQ or Inngest for background jobs
- File storage: S3/R2 for user uploads
- Monitoring: Sentry, Datadog, PostHog for observability
- Infrastructure: Vercel + AWS/Railway, or similar
Development Phases
Phase 1: MVP (4-8 weeks)
- Core product feature (the one thing that solves the problem)
- Basic auth (email + Google SSO)
- Simple billing (one paid plan + Stripe)
- Marketing landing page
Phase 2: Growth (8-16 weeks)
- Team features and collaboration
- Multiple pricing tiers with feature gating
- API for integrations
- Onboarding optimization
- Analytics and usage tracking
Phase 3: Scale (16-30 weeks)
- Multi-tenancy hardening
- Enterprise features (SSO, audit log, data export)
- Advanced billing (usage-based, annual contracts)
- Admin dashboard for internal operations
- SOC 2 compliance preparation
Common Development Mistakes
- Building features before validating demand with real users
- Over-engineering infrastructure for scale you don't have yet
- Rolling your own auth instead of using established providers
- Not implementing proper multi-tenancy from the start
- Missing webhook handling for Stripe (billing bugs are revenue-killing)
- No feature flags (stuck with big-bang deployments)
- Ignoring mobile responsiveness for the app
- Conflating marketing site with product architecture
Development Timeline & Cost
- MVP: 6-12 weeks, $20,000-$60,000
- Growth stage: Additional 12-20 weeks, $40,000-$100,000
- Enterprise features: Additional 12-24 weeks, $50,000-$150,000
Conclusion
SaaS web development is iterative product engineering. Start with an MVP that solves one problem extremely well, then layer in billing, team features, and enterprise capabilities as revenue justifies the investment. The architecture decisions made early — especially around auth and multi-tenancy — determine how painfully you can scale later.
Ready to build your SaaS product? Contact RCB Software for a free consultation, or learn more about our web development services.