codexmachina
registry/nextjs-mysql-clerk-saas

SaaS on Next.js 16 (App Router), MySQL 8 and Clerk

verified 2026-07-15next16.2.9mysql23.22.6postgres3.4.9@clerk/nextjs7.5.15@polar-sh/sdk0.48.1@neondatabase/serverless1.1.0

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

request path
Browserrequest
fetch
Next.js 16 (App Router)routing + proxy
verify
Clerksession
query
MySQL 8pooled

session validation runs in server components and route handlers, not at the edge

What you're getting

Next.js 16 (App Router)

Next.js 16 App Router — file-based routing, server components, and the Edge proxy (Next 16's renamed middleware).

MySQL 8

MySQL 8 via Drizzle ORM and the mysql2 driver.

Clerk

Clerk — hosted identity (sign-in UI, sessions, user management) mounted via middleware + provider.

SaaS

Multi-tenant SaaS — organizations, role-based memberships, plans/subscriptions, and credit metering.

Setup

bun add next react react-dom drizzle-orm mysql2 @clerk/nextjs
DATABASE_URLMySQL connection string (mysql://…)
NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY
CLERK_SECRET_KEY
CLERK_WEBHOOK_SECRETsvix secret that verifies Clerk webhook signatures

Apply the schema with bunx drizzle-kit push

Initialization

Database client

src/lib/db.ts
import { drizzle } from "drizzle-orm/mysql2";
import mysql from "mysql2/promise";

// ponytail: single module-level pool; the runtime + mysql2's pool handle concurrency,
// so no globalThis singleton dance needed.
const pool = mysql.createPool(process.env.DATABASE_URL!);

export const db = drizzle({ client: pool });

// ponytail: Clerk is hosted — set NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY and
// CLERK_SECRET_KEY in the env. The publishable key is read client-side by
// <ClerkProvider>; the secret key is read server-side by clerkMiddleware().
// Both are picked up from the environment automatically — no wiring needed.
// Clerk proxy for Next.js 16 (App Router) (Next 16 renamed middleware.ts → proxy.ts; clerkMiddleware is still the helper).
import { clerkMiddleware, createRouteMatcher } from "@clerk/nextjs/server";

// ponytail: guard the SaaS app surface; widen the matcher per app-type.
const isProtectedRoute = createRouteMatcher([
  "/dashboard(.*)",
  "/settings(.*)",
]);

export default clerkMiddleware(async (auth, request) => {
  // auth.protect() bounces logged-out users to Clerk's hosted sign-in.
  if (isProtectedRoute(request)) {
    await auth.protect();
  }
});

export const config = {
  // Clerk's documented matcher: skip Next internals + static files unless
  // referenced in search params, and always run on API/tRPC routes.
  matcher: [
    "/((?!_next|[^?]*\\.(?:html?|css|js(?!on)|jpe?g|webp|png|gif|svg|ttf|woff2?|ico|csv|docx?|xlsx?|zip|webmanifest)).*)",
    "/(api|trpc)(.*)",
  ],
};
// Root layout — <ClerkProvider> is required for Next.js 16 (App Router).
import { ClerkProvider } from "@clerk/nextjs";
import type { ReactNode } from "react";

export default function RootLayout({ children }: { children: ReactNode }) {
  return (
    <ClerkProvider>
      <html lang="en">
        <body>{children}</body>
      </html>
    </ClerkProvider>
  );
}

Multi-tenant SaaS schema: organizations, billing & usage metering

Organizations & multi-tenancy

the tenant boundary every billable and metered row hangs off

Memberships & role-based access

org↔user join carrying owner/admin/member roles, unique per pair

Plans & subscription billing tables

the billable plan catalog and each org's current subscription state

API usage & credit/token metering

append-only usage rows that drive quota checks and usage billing

src/db/schema.ts
// === file: src/db/schema.ts ===
import { relations, sql } from "drizzle-orm";
import {
  bigint,
  check,
  index,
  int,
  mysqlTable,
  text,
  timestamp,
  unique,
  varchar,
} from "drizzle-orm/mysql-core";
// Better Auth owns identity; we only reference its `user` table by id. With Clerk
// the identity-sync mirror occupies this same ./auth-schema slot (src/db/auth-schema.ts).
import { user } from "./auth-schema";

export type MemberRole = "owner" | "admin" | "member";
export type SubscriptionStatus =
  | "trialing"
  | "active"
  | "past_due"
  | "canceled";

/** Tenant boundary: every billable/metered row hangs off an organization. */
export const organizations = mysqlTable(
  "organizations",
  {
    id: varchar("id", { length: 36 }).primaryKey(),
    slug: varchar("slug", { length: 255 }).notNull().unique(),
    name: text("name").notNull(),
    createdAt: timestamp("created_at").notNull().defaultNow(),
  },
  (t) => [index("idx_org_slug").on(t.slug)],
);

/** org <-> user join with role. The composite unique is the membership identity. */
export const memberships = mysqlTable(
  "memberships",
  {
    id: varchar("id", { length: 36 }).primaryKey(),
    organizationId: varchar("organization_id", { length: 36 })
      .notNull()
      .references(() => organizations.id, { onDelete: "cascade" }),
    // Better Auth's user.id is text — match it as varchar(255).
    userId: varchar("user_id", { length: 255 })
      .notNull()
      .references(() => user.id, { onDelete: "cascade" }),
    role: varchar("role", { length: 32 }).$type<MemberRole>().notNull().default("member"),
    createdAt: timestamp("created_at").notNull().defaultNow(),
  },
  (t) => [
    unique("memberships_org_user_unique").on(t.organizationId, t.userId),
    index("idx_membership_user").on(t.userId),
    check(
      "memberships_role_check",
      sql`${t.role} in ('owner','admin','member')`,
    ),
  ],
);

/** Catalog of billable plans (seed-managed). priceCents keeps money integer. */
export const plans = mysqlTable("plans", {
  id: varchar("id", { length: 36 }).primaryKey(),
  slug: varchar("slug", { length: 255 }).notNull().unique(), // free | pro | scale
  name: text("name").notNull(),
  priceCents: int("price_cents").notNull().default(0),
  // Monthly included credits; metering checks usage against this.
  monthlyCredits: bigint("monthly_credits", { mode: "number" })
    .notNull()
    .default(0),
});

/** One active subscription per org. Mirrors the billing provider's state. */
export const subscriptions = mysqlTable(
  "subscriptions",
  {
    id: varchar("id", { length: 36 }).primaryKey(),
    organizationId: varchar("organization_id", { length: 36 })
      .notNull()
      .references(() => organizations.id, { onDelete: "cascade" }),
    planId: varchar("plan_id", { length: 36 })
      .notNull()
      .references(() => plans.id),
    status: varchar("status", { length: 32 })
      .$type<SubscriptionStatus>()
      .notNull()
      .default("trialing"),
    // The generic billing-sync contract every webhook provider (Polar/Stripe/LemonSqueezy)
    // needs: the provider's subscription id as a UNIQUE idempotency key, plus the last
    // event timestamp as an out-of-order/staleness guard. The billing fragment maps a
    // provider's events onto these — it does NOT redeclare this table (compose, not duplicate).
    providerSubId: varchar("provider_sub_id", { length: 255 }).unique(),
    providerEventAt: timestamp("provider_event_at"),
    currentPeriodEnd: timestamp("current_period_end"),
    createdAt: timestamp("created_at").notNull().defaultNow(),
  },
  (t) => [
    // One live subscription per org (the metering layer reads exactly one).
    unique("subscriptions_org_unique").on(t.organizationId),
    index("idx_sub_status").on(t.status),
    check(
      "subscriptions_status_check",
      sql`${t.status} in ('trialing','active','past_due','canceled')`,
    ),
  ],
);

/** Append-only credit/token meter. Roll up by org+window for quota + billing. */
export const apiUsage = mysqlTable(
  "api_usage",
  {
    id: varchar("id", { length: 36 }).primaryKey(),
    organizationId: varchar("organization_id", { length: 36 })
      .notNull()
      .references(() => organizations.id, { onDelete: "cascade" }),
    // Who/what spent — opaque key id, nullable for org-level system calls.
    apiKeyId: text("api_key_id"),
    creditsUsed: bigint("credits_used", { mode: "number" }).notNull(),
    createdAt: timestamp("created_at").notNull().defaultNow(),
  },
  (t) => [
    // Drives the "credits used this period" rollup query.
    index("idx_usage_org_time").on(t.organizationId, t.createdAt),
  ],
);

export const organizationsRelations = relations(organizations, ({ many }) => ({
  memberships: many(memberships),
  subscriptions: many(subscriptions),
  usage: many(apiUsage),
}));

export const membershipsRelations = relations(memberships, ({ one }) => ({
  organization: one(organizations, {
    fields: [memberships.organizationId],
    references: [organizations.id],
  }),
  user: one(user, { fields: [memberships.userId], references: [user.id] }),
}));

export const subscriptionsRelations = relations(subscriptions, ({ one }) => ({
  organization: one(organizations, {
    fields: [subscriptions.organizationId],
    references: [organizations.id],
  }),
  plan: one(plans, {
    fields: [subscriptions.planId],
    references: [plans.id],
  }),
}));

export const apiUsageRelations = relations(apiUsage, ({ one }) => ({
  organization: one(organizations, {
    fields: [apiUsage.organizationId],
    references: [organizations.id],
  }),
}));

Verified billing (Polar)

✓ Idempotency proven: a duplicate webhook delivery yields one subscription, not two; a stale, out-of-order event can't overwrite newer state. Replayed against a live database, not just type-checked.
src/lib/billing/record.ts
import { and, eq, isNull, lt, or } from "drizzle-orm";
import { subscriptions } from "@/db/schema";

export type PolarSubscriptionEvent = {
  type: string;
  data: {
    id: string;
    status: string;
    currentPeriodEnd: string | null;
    modifiedAt: string;
    metadata: { organizationId: string; planId: string };
  };
};

const STATUS_MAP: Record<string, "trialing" | "active" | "past_due" | "canceled"> = {
  trialing: "trialing",
  active: "active",
  past_due: "past_due",
  unpaid: "past_due",
  canceled: "canceled",
  revoked: "canceled",
};

// Idempotent + CONCURRENCY-safe sync of a Polar subscription (MySQL). The staleness guard lives
// in the UPDATE's WHERE, so the row lock serializes concurrent retries. MySQL has no RETURNING —
// affectedRows tells us if a row advanced. The insert path catches the unique-key race (a
// concurrent delivery of the same NEW event) as an idempotent no-op, rethrowing every other error.
// Returns changed=true only on a real advance so callers can guard side effects (emails) against
// Polar's duplicate deliveries.
export async function recordPolarEvent(
  // ponytail: loosely typed Drizzle client so the emitted core stays portable.
  db: any,
  event: PolarSubscriptionEvent,
): Promise<{ changed: boolean }> {
  const sub = event.data;
  const status = STATUS_MAP[sub.status];
  if (!status) return { changed: false }; // unknown status — ignore, don't default
  const eventAt = new Date(sub.modifiedAt);
  const currentPeriodEnd = sub.currentPeriodEnd ? new Date(sub.currentPeriodEnd) : null;

  // Guarded UPDATE: applies only when our event is strictly newer than what's stored.
  // No TOCTOU — the comparison is in the WHERE, evaluated under the row lock.
  const updated = await db
    .update(subscriptions)
    .set({ status, currentPeriodEnd, providerEventAt: eventAt })
    .where(
      and(
        eq(subscriptions.providerSubId, sub.id),
        or(isNull(subscriptions.providerEventAt), lt(subscriptions.providerEventAt, eventAt)),
      ),
    );
  if (updated[0].affectedRows > 0) return { changed: true };

  // No row advanced: the row exists but our event is stale (guard rejected it), or it doesn't
  // exist yet. If it exists, this is a stale/duplicate delivery — ignore.
  const [existing] = await db
    .select({ id: subscriptions.id })
    .from(subscriptions)
    .where(eq(subscriptions.providerSubId, sub.id))
    .limit(1);
  if (existing) return { changed: false };

  // The row doesn't exist yet — insert it. A concurrent delivery of the SAME new subscription can
  // win the race between our SELECT and this INSERT; the unique key then rejects ours (ER_DUP_ENTRY)
  // — an idempotent no-op, NOT a change. Any other error is real: rethrow so the webhook fails loud
  // and Polar retries.
  try {
    await db.insert(subscriptions).values({
      id: crypto.randomUUID(),
      organizationId: sub.metadata.organizationId,
      planId: sub.metadata.planId,
      status,
      currentPeriodEnd,
      providerSubId: sub.id,
      providerEventAt: eventAt,
    });
    return { changed: true };
  } catch (err: any) {
    if ((err?.cause?.code ?? err?.code) === "ER_DUP_ENTRY") return { changed: false };
    throw err;
  }
}
// Polar webhook for Next.js 16 (App Router). Verifies the HMAC signature, then hands the
// event to the idempotent recordPolarEvent. Returns 200 even if non-critical work
// fails; only a signature failure is rejected.
import { validateEvent, WebhookVerificationError } from "@polar-sh/sdk/webhooks";
import { db } from "@/lib/db";
import { recordPolarEvent, type PolarSubscriptionEvent } from "@/lib/billing/record";

const SUBSCRIPTION_EVENTS = new Set([
  "subscription.created",
  "subscription.active",
  "subscription.updated",
  "subscription.canceled",
  "subscription.revoked",
  "subscription.uncanceled",
]);

export async function POST(request: Request): Promise<Response> {
  const secret = process.env.POLAR_WEBHOOK_SECRET;
  if (!secret) return Response.json({ error: "Server misconfigured" }, { status: 500 });

  const raw = await request.text();
  const headers = Object.fromEntries(request.headers.entries());

  let event: { type: string; data: unknown };
  try {
    event = validateEvent(raw, headers, secret);
  } catch (error) {
    if (error instanceof WebhookVerificationError) {
      return Response.json({ error: "Invalid signature" }, { status: 403 });
    }
    throw error;
  }

  if (SUBSCRIPTION_EVENTS.has(event.type)) {
    await recordPolarEvent(db, event as PolarSubscriptionEvent);
  }
  return Response.json({ ok: true });
}

Verified tenant scoping

✓ Enforced in application code: MySQL 8 has no row-level security, so isolation runs through the fail-closed forOrg(db, orgId) helper. Route every org-scoped query through it; a raw query does leak. See the decisions below.
src/lib/tenant.ts
import { eq } from "drizzle-orm";
import { memberships, subscriptions, apiUsage } from "@/db/schema";

// MySQL has NO row-level security. Tenant isolation is enforced HERE: route EVERY org-scoped
// read/write through forOrg(db, orgId). Fail-closed — a missing orgId throws rather than running
// unscoped. The global `plans` catalog is intentionally NOT scoped.
export function forOrg(db: any, orgId: string) {
  if (!orgId) throw new Error("forOrg: missing orgId — refusing to run an unscoped tenant query");
  const scoped = (table: any, orgCol: any) => ({
    select: () => db.select().from(table).where(eq(orgCol, orgId)),
    update: (values: Record<string, unknown>) => db.update(table).set(values).where(eq(orgCol, orgId)),
    delete: () => db.delete(table).where(eq(orgCol, orgId)),
  });
  return {
    memberships: scoped(memberships, memberships.organizationId),
    subscriptions: scoped(subscriptions, subscriptions.organizationId),
    apiUsage: scoped(apiUsage, apiUsage.organizationId),
  };
}

Verified identity sync (Clerk)

✓ Clerk users sync into a local user table idempotently: duplicate, out-of-order, and concurrent webhooks converge to one correct row. Replayed against a live database.
src/db/auth-schema.ts
// === file: src/db/auth-schema.ts ===
import { mysqlTable, text, timestamp, varchar } from "drizzle-orm/mysql-core";

// Local mirror of Clerk identity — the FK target app-type schemas reference as user.
// id = Clerk's user id (varchar(255), matching the app-type user_id FKs), so existing
// user_id foreign keys resolve once the sync runs. This IS the auth-schema slot for Clerk cells.
export const user = mysqlTable("user", {
  id: varchar("id", { length: 255 }).primaryKey(), // = Clerk user id
  email: text("email"),
  firstName: text("first_name"),
  lastName: text("last_name"),
  imageUrl: text("image_url"),
  updatedAt: timestamp("updated_at"), // staleness key (Clerk updated_at)
  createdAt: timestamp("created_at").notNull().defaultNow(),
});

import { and, eq, isNull, lt, or } from "drizzle-orm";
import { user } from "@/db/auth-schema";

export type ClerkUserEvent = {
  type: string;
  data: {
    id: string;
    email_addresses?: { email_address: string }[];
    first_name?: string | null;
    last_name?: string | null;
    image_url?: string | null;
    updated_at?: number;
  };
};

// Idempotent + concurrency-safe sync of a Clerk user into the local user table (MySQL).
// Keyed on id (= Clerk id, the PK); the staleness guard lives in the UPDATE WHERE. MySQL has no
// RETURNING — affectedRows tells us what happened. The insert path catches the unique-key race (a
// concurrent delivery of the same NEW user) as an idempotent no-op, rethrowing every other error.
// user.deleted removes the row.
export async function recordClerkEvent(
  // ponytail: loosely typed Drizzle client so the emitted core stays portable.
  db: any,
  event: ClerkUserEvent,
): Promise<{ changed: boolean }> {
  const d = event.data;
  if (event.type === "user.deleted") {
    const deleted = await db.delete(user).where(eq(user.id, d.id));
    return { changed: deleted[0].affectedRows > 0 };
  }

  const email = d.email_addresses?.[0]?.email_address ?? null;
  const eventAt = new Date(d.updated_at ?? 0);
  const fields = {
    email,
    firstName: d.first_name ?? null,
    lastName: d.last_name ?? null,
    imageUrl: d.image_url ?? null,
    updatedAt: eventAt,
  };

  const updated = await db
    .update(user)
    .set(fields)
    .where(and(eq(user.id, d.id), or(isNull(user.updatedAt), lt(user.updatedAt, eventAt))));
  if (updated[0].affectedRows > 0) return { changed: true };

  const [existing] = await db.select({ id: user.id }).from(user).where(eq(user.id, d.id)).limit(1);
  if (existing) return { changed: false };

  // The row doesn't exist yet — insert it. A concurrent delivery of the SAME new user can win the
  // race between our SELECT and this INSERT; the PK then rejects ours (ER_DUP_ENTRY) — an idempotent
  // no-op, NOT a change. Any other error is real: rethrow so the webhook fails loud and Clerk retries.
  try {
    await db.insert(user).values({ id: d.id, ...fields });
    return { changed: true };
  } catch (err: any) {
    if ((err?.cause?.code ?? err?.code) === "ER_DUP_ENTRY") return { changed: false };
    throw err;
  }
}
// Clerk identity webhook for Next.js 16 (App Router). Clerk webhooks are svix — verify the
// signature, then hand the event to the idempotent recordClerkEvent.
import { Webhook } from "svix";
import { db } from "@/lib/db";
import { recordClerkEvent, type ClerkUserEvent } from "@/lib/identity/record";

const USER_EVENTS = new Set(["user.created", "user.updated", "user.deleted"]);

export async function POST(request: Request): Promise<Response> {
  const secret = process.env.CLERK_WEBHOOK_SECRET;
  if (!secret) return Response.json({ error: "Server misconfigured" }, { status: 500 });

  const raw = await request.text();
  const headers = Object.fromEntries(request.headers.entries());

  let event: ClerkUserEvent;
  try {
    event = new Webhook(secret).verify(raw, headers) as ClerkUserEvent;
  } catch {
    return Response.json({ error: "Invalid signature" }, { status: 403 });
  }

  if (USER_EVENTS.has(event.type)) await recordClerkEvent(db, event);
  return Response.json({ ok: true });
}

Deploy targets

✓ The right DB client for where you deploy: load-tested with concurrent queries against a live database. Edge needs the HTTP driver (no TCP); serverless needs a tiny pool.
src/lib/db.ts
import { drizzle } from "drizzle-orm/mysql2";
import mysql from "mysql2/promise";

// Serverless: a small pool per short-lived instance — many instances × a big pool exhausts MySQL.
export const pool = mysql.createPool({ uri: process.env.DATABASE_URL!, connectionLimit: 2 });
export const db = drizzle({ client: pool });

import { drizzle } from "drizzle-orm/mysql2";
import mysql from "mysql2/promise";

// Long-running process: a real, reused pool (mysql2 manages idle recycling).
export const pool = mysql.createPool({ uri: process.env.DATABASE_URL!, connectionLimit: 10 });
export const db = drizzle({ client: pool });

import { drizzle } from "drizzle-orm/planetscale-serverless";
import { Client } from "@planetscale/database";

// Edge/Workers have NO TCP sockets, so mysql2 cannot run here. PlanetScale's HTTP driver
// speaks MySQL over fetch — the client that works on Workers (the MySQL analog of Neon's HTTP driver).
const client = new Client({ url: process.env.DATABASE_URL! });
export const db = drizzle({ client });

Decisions and compatibility

note

Auth runs in proxy.ts (Next 16's renamed middleware) on the Edge runtime: it gates on the session cookie's presence only — full session validation happens in Server Components and route handlers, not in the proxy.

note

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.

note

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.

note

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`.

note

One active subscription per organization (unique on organization_id) — the metering layer reads exactly one.

note

Usage is an append-only meter (api_usage): roll up by organization + time window for quota and billing rather than mutating a running total.

caveat

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.

caveat

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.