Custom SaaS Platform: What It Costs to Build Your Own Multi-Tenant App

You have a product idea, or you've validated demand for a tool your customers are asking for, and you're considering building it as a SaaS rather than reselling someone else's. Smart move — but the cost structure is meaningfully different from internal-use software, and most cost estimates online are wildly off.

Here's what custom SaaS platforms actually cost to build in 2026, what makes them different, and what to expect.

The headline number

Most custom SaaS platforms in 2026 launch at MVP for $40k–$150k. Production-ready scale (handling 100+ paying customer accounts) typically costs another $60–200k on top, depending on architectural needs.

Total range: $40k (lean MVP for early validation) to $400k+ (enterprise-grade multi-tenant platform).

What makes SaaS different from internal software

A custom internal tool runs for your one company. A SaaS platform runs for many. That changes five things.

1. Multi-tenancy

Your data architecture has to isolate customer data securely while sharing infrastructure. Three approaches:

Database-per-tenant — strongest isolation, highest cost, best for enterprise

Schema-per-tenant — middle ground, common for mid-market SaaS

Shared schema with tenant_id — cheapest, most common for early SaaS, requires careful query design

2. Authentication and onboarding

Each customer needs their own admin, user management, branding, billing. SSO is increasingly expected (Google, Microsoft, SAML/OIDC). Self-serve signup vs sales-assisted onboarding has different UX patterns.

3. Billing

Stripe Billing or Chargebee for subscription management. Trial periods, upgrade/downgrade flows, dunning (failed payment retries), prorated billing, annual vs monthly, multi-tier pricing. This alone is 2–4 weeks of work.

4. Admin tooling

You need admin tooling to debug customer issues, see what's happening per-tenant, manage billing exceptions, handle support escalations. Easy to forget at MVP, painful to add later.

5. Customer-facing analytics

Your customers want dashboards showing their data, their usage, their team's activity. The reporting layer is often 20–30% of the platform's work.

Three worked examples

Tier 1 — Lean MVP ($40k–$80k)

1 primary user role per tenant

Stripe Checkout for self-serve billing (1–2 tiers)

5–10 core feature pages

Shared-schema multi-tenancy

Basic admin tooling

8–12 week build

Built to validate market fit at 5–30 paying customers, not to scale to 500.

Tier 2 — Production-ready SaaS ($90k–$180k)

3–5 user roles, team management within tenants

Full Stripe Billing integration (trials, upgrades, dunning)

15–30 feature pages

Schema-per-tenant or carefully-designed shared schema

Admin tooling with impersonation, billing override, usage analytics

SSO (Google, Microsoft) + email auth

Customer-facing analytics

API for customer integrations

12–20 week build

Built to scale to 100–500 customer accounts.

Tier 3 — Enterprise SaaS ($200k–$400k+)

Multi-team per tenant with custom roles

Database-per-tenant or strong schema isolation

Enterprise SSO (SAML/OIDC, custom IdPs)

Custom domains, white-label, branded emails

SOC 2, GDPR, HIPAA depending on industry

Custom workflow engine + integration platform

Full admin tooling with audit logs, customer impersonation, billing exceptions

Multi-region deployment

20–32 week build

Built for 100–5000+ customer accounts including enterprise contracts.

What's NOT in those numbers

Hosting infrastructure ($200–$5,000/month depending on scale), payment processing fees (Stripe ~2.9% + $0.30/transaction), email delivery ($30–300/month), monitoring/observability ($50–500/month), customer support tooling, and ongoing engineering work as you scale.

Budget another 1–3% of revenue for ongoing platform engineering once you're past MVP.

The "build it then sell it" path

Many SaaS founders bootstrap with revenue-share or hosted models — no upfront cost, paid back as the platform earns. Our engagement models guide covers when this makes sense.

For a transparent cost estimate for your specific SaaS scope, our cost calculator gives a range in 60 seconds. Or contact us to discuss revenue-share fit.