Web App Development
SaaS Web App Development That Drives Recurring Revenue
We build SaaS web apps with the subscription infrastructure, onboarding flows, and multi-tenant architecture that convert trials to paying customers — shipped in under 2 weeks.
Why SaaS Web App Development Is Different
Building SaaS is not just writing features — it is wiring together a revenue engine. Every SaaS web app needs subscription management, customer onboarding flows, usage tracking, billing portals, and multi-tenancy architecture that does not collapse when you go from 100 to 10,000 customers. Most agencies treat SaaS like a regular web app with a Stripe button bolted on. That is how you end up with a churn problem baked into the architecture before your first paying customer signs up.
The onboarding flow is where SaaS companies make or lose users, and most development agencies skip it entirely in the first build. At Greta, we treat the activation moment — the first time a user does the thing your product promises — as a first-class engineering concern. We build progress bars, empty states, onboarding checklists, and contextual tooltips into the initial build. These features typically move activation rates by 20–40%, based on what we have measured in PLGOS and other SaaS builds.
SaaS web app development also means building for scale you do not have yet. Your PostgreSQL schema needs to be designed for multi-tenancy from day one. Your Stripe integration needs webhooks that handle failed payments, trial expirations, plan upgrades, and proration automatically — without manual intervention. These architectural decisions are expensive to retrofit. We have made them correctly across 20+ SaaS builds and we bake them in from the start, not as a phase two sprint.
Our Approach to Saas web app development
Every project follows our 4-step vibe-coding process — AI handles the boilerplate, senior engineers handle the craft. From idea to live product in 3–7 days for MVPs.
Discovery
We map your core SaaS user journey: acquisition, activation, retention, and expansion. We ask which onboarding step is the activation event, where users first hit a paywall, and what triggers churn. These answers shape the data model and feature prioritization for your SaaS web app build — because a SaaS product that does not understand its own funnel will not improve it.
Design
We wireframe the full SaaS UI system: marketing landing page, sign-up flow, onboarding checklist, core product dashboard, settings panel, and billing portal. Every screen is designed with the SaaS user journey in mind, not just visual aesthetics. We validate the end-to-end flow in Figma before writing any code.
Build
Multi-tenant architecture with Supabase Row Level Security, Stripe Billing with webhooks for payment lifecycle events, role-based access control for team features, and a Next.js 15 App Router frontend. Our AI generates the scaffolding for standard patterns — auth, subscription management, API routes — and our engineers build the differentiated product logic.
Launch
Staged launch: first to internal beta, then to invited early users, then to public. We configure Stripe's test mode for payment flow validation, run a full billing cycle simulation before go-live, and set up error monitoring dashboards specific to the critical SaaS paths: sign-up, trial activation, and first payment.
What You Get
Every saas web app development engagement includes these deliverables — scoped before we start, delivered before we invoice.
- Multi-tenant SaaS architecture with Supabase Row Level Security data isolation
- Stripe Billing integration: subscriptions, trials, proration, dunning, and billing portal
- User onboarding flow with progress tracking, empty states, and activation milestone events
- Team workspace features: member invitations, role assignment, and shared settings
- Usage metering and feature-gating based on subscription tier
- Admin dashboard for customer management, revenue metrics, and subscription overrides
- Webhook handler for Stripe events: payment success, failure, cancellation, and upgrade
- Automated email triggers: welcome, trial expiry, payment failed, and churn recovery
- Analytics event tracking for activation funnel and feature adoption
- Deployment on Vercel with environment separation for staging and production
Tech Stack We Use
SaaS web app development at Greta runs on Next.js 15 with App Router for the frontend, Supabase for multi-tenant PostgreSQL with Row Level Security, and Stripe Billing for the revenue infrastructure. We add TypeScript throughout for type-safe API contracts between frontend and backend, Tailwind CSS for the design system, and Vercel for deployment with preview environments per pull request. For SaaS-specific needs: PostHog for product analytics and activation funnel tracking, Resend for transactional emails, and Sentry for error monitoring with environment-scoped alerting. We have used this stack to build 20+ SaaS products and know exactly which configurations are production-battle-tested.
Case Study
PLGOS — 2.4× Activation Rate Improvement
PLGOS is a product-led growth operating system — a SaaS tool for tracking activation events, running A/B tests on onboarding flows, and surfacing churn-risk signals before customers cancel. We built it from scratch in 11 days: multi-tenant architecture with Supabase RLS, Stripe subscriptions with metered billing, a real-time analytics dashboard, and a webhook system for capturing user activation events from third-party products. The founder measured a 2.4× improvement in activation rate over their previous manual tracking process. PLGOS reached 340 paying customers within 60 days of launch and has maintained sub-3% monthly churn since.
Read full case studyPricing Transparency
SaaS web app development starts at $5,000 for an MVP with authentication, a core product flow, and Stripe subscription integration. Full SaaS builds — multi-tenancy, team workspaces, billing portal, admin dashboard, usage metering — run $15,000–$40,000 depending on scope. Every project includes full code ownership, two revision rounds, Vercel deployment, and one week of post-launch support. Ongoing retainer arrangements are available for SaaS teams who want continued development velocity.
MVP
From $5,000
3–7 business days
Full Build
From $15,000
2–4 weeks
All projects include full code ownership, two revision rounds, Vercel deployment, and one week of post-launch support. No hidden fees.
Frequently Asked Questions
How do you handle multi-tenancy in a SaaS web app?
We use Supabase Row Level Security policies to enforce tenant isolation at the database level. Every query automatically filters to the current user's organization, making cross-tenant data leaks structurally impossible — not just guarded by application code. We design the tenant architecture during discovery and validate it before building a single feature.
Can you set up Stripe subscriptions with trials and proration?
Yes. We configure Stripe Billing with trial periods, plan upgrades and downgrades with prorated charges, failed payment recovery via Stripe's smart retry logic, and a customer portal for self-serve plan management. We also set up all required webhook handlers so subscription state stays in sync with your database automatically.
How long does SaaS web app development take?
An MVP SaaS — auth, core product flow, Stripe subscription, and basic dashboard — takes 5–10 days. A full SaaS with multi-tenancy, team workspaces, admin panel, and usage metering takes 2–4 weeks. We scope precisely before starting so there are no mid-project timeline surprises.
Do you build the marketing landing page too?
Yes, if it is in scope. Many SaaS clients want the marketing site and app under one Next.js project. We build both and configure the domain routing so app.yourproduct.com serves the web app and yourproduct.com serves the marketing site. This is a standard part of our SaaS web app development scope.
Can you integrate with my existing CRM or data warehouse?
We can integrate with CRMs (HubSpot, Salesforce) and data tools (Segment, Mixpanel) via API. The feasibility and cost depends on the integration complexity. We assess third-party integrations during discovery and price them as separate line items in the project scope.
What analytics do you include for tracking SaaS metrics?
We configure PostHog for product analytics — activation events, feature adoption, conversion funnel, and session recording. For revenue metrics, we connect Stripe data to a simple dashboard showing MRR, churn rate, and trial conversion. These are standard on every SaaS build.
Will my SaaS web app scale to thousands of users?
Yes. Supabase handles millions of rows with proper indexing, Vercel's edge network scales automatically, and our architecture avoids the common scaling antipatterns — N+1 queries, unindexed sort columns, connection pool exhaustion. We have built SaaS apps that scaled from 0 to 10,000 users on the same codebase we shipped in week one.
Do you own any part of the SaaS product we build together?
No. You own 100% of the code, the IP, and the product. We assign all rights to you at handoff. We do not retain any license, usage rights, or claim to the codebase. Greta builds your product; you own your product.
Ready to ship?
Ready to build your SaaS web app?
Start Your ProjectOr reach us directly at hello@greta.agency
Written by the Greta Agency team · Last updated April 2025