SaaS on React Router v8, MySQL 8 and Clerk
Type-checked against the real SDKs, migration applied to a live MySQL 8, connection clients load-tested, then tracked for upstream drift and re-verified when it moves. How we verify
session validation runs in server components and route handlers, not at the edge
What you're getting
React Router v8 (framework mode) — SSR, config/file routes under app/, loaders/actions, and resource routes for API endpoints.
MySQL 8 via Drizzle ORM and the mysql2 driver.
Clerk — hosted identity (sign-in UI, sessions, user management) mounted via middleware + provider.
Multi-tenant SaaS — organizations, role-based memberships, plans/subscriptions, and credit metering.
Setup
bun add react-router react react-dom drizzle-orm mysql2 @clerk/nextjsDATABASE_URLMySQL connection string (mysql://…)NEXT_PUBLIC_CLERK_PUBLISHABLE_KEYCLERK_SECRET_KEYCLERK_WEBHOOK_SECRETsvix secret that verifies Clerk webhook signaturesApply the schema with bunx drizzle-kit push
Initialization
Database client
Multi-tenant SaaS schema: organizations, billing & usage metering
Organizations & multi-tenancythe tenant boundary every billable and metered row hangs off
Memberships & role-based accessorg↔user join carrying owner/admin/member roles, unique per pair
Plans & subscription billing tablesthe billable plan catalog and each org's current subscription state
API usage & credit/token meteringappend-only usage rows that drive quota checks and usage billing
Verified billing (Polar)
Verified tenant scoping
Verified identity sync (Clerk)
Deploy targets
Decisions and compatibility
Framework mode (not data/library mode): routes live under app/, declared in app/routes.ts. API endpoints are resource routes (a route module exporting loader/action but no default component).
mysql2's pool multiplexes connections; drizzle-orm/mysql2 wraps it. One module-level pool is right for a serverless/edge app — the runtime and the pool handle concurrency.
MySQL has no row-level security: multi-tenant isolation is enforced in application code via the forOrg helper (src/lib/tenant.ts), not by the database. See the tenant-scoping section on SaaS pages.
Hosted: Clerk owns identity and does NOT create a local `user` table. Store `clerk_user_id` as text without a foreign key, or sync Clerk users into a local table via webhook before relying on FKs to `user`.
One active subscription per organization (unique on organization_id) — the metering layer reads exactly one.
Usage is an append-only meter (api_usage): roll up by organization + time window for quota and billing rather than mutating a running total.
Clerk is a hosted identity provider and does not create a local `user` table. This schema's foreign keys to `user` assume a local identity table (as Better Auth provides). With Clerk, store `clerk_user_id` as a text column without a foreign key, or sync Clerk users into a local `users` table via webhook before relying on these FKs.
MySQL provides no row-level security. On MySQL, multi-tenant isolation is APP-ENFORCED via the forOrg helper (src/lib/tenant.ts), not database-enforced like Postgres RLS. Every org-scoped query MUST go through forOrg — a missed query leaks across tenants. Postgres cells enforce this in the database itself (RLS), so it holds even for a query that forgets to scope.