☁️ SaaS & Cloud · C4 Architecture · Pro
Multi-Tenant SaaS Architecture
A B2B SaaS product serving many customer organisations from one platform: tenant-aware services, per-tenant data isolation, billing and admin.
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Drawing diagram…
What this diagram shows
- Every request carries a tenant ID checked at the gateway
- Tenant data is isolated by schema, or a dedicated database for enterprise
- Subscription billing and feature flags per plan
Prompt used
Multi-tenant SaaS architecture: users from many customer organisations sign in through an auth service (SSO/SAML per tenant), the API gateway resolves the tenant from the subdomain and token. Services: tenant management (plans, limits, feature flags), core application services, a shared PostgreSQL with schema per tenant (dedicated database for enterprise tenants), a billing service integrated with Stripe/Razorpay, audit logging, and a background job queue.
Mermaid code
C4Container
title Multi-Tenant SaaS
Person(user, "Tenant User", "Works in their organisation's space")
Person(admin, "Tenant Admin", "Manages users and billing")
System_Ext(idp, "Customer IdP", "SSO / SAML")
System_Ext(pay, "Billing Provider", "Stripe / Razorpay")
System_Boundary(saas, "SaaS Platform") {
Container(web, "Web App", "React", "acme.app.com")
Container(gw, "API Gateway", "Envoy", "Resolves tenant, rate limits")
Container(auth, "Auth Service", "Go", "Login, SSO per tenant")
Container(tenant, "Tenant Service", "Go", "Plans, limits, feature flags")
Container(core, "Core Services", "Node.js", "Product features")
Container(jobs, "Job Workers", "Node.js", "Exports, emails")
ContainerDb(db, "PostgreSQL", "Schema per tenant", "Tenant data")
Container(billing, "Billing Service", "Go", "Subscriptions and invoices")
}
Rel(user, web, "Uses")
Rel(admin, web, "Uses")
Rel(web, gw, "Calls")
Rel(gw, auth, "Verifies")
Rel(auth, idp, "SAML")
Rel(gw, core, "Routes with tenant ID")
Rel(core, tenant, "Checks limits")
Rel(core, db, "Tenant schema")
Rel(core, jobs, "Queues work")
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