codexmachina
registry/react-router-postgres-better-auth-saas

SaaS on React Router v8, Postgres (Neon) and Better Auth

verified 2026-07-15postgres3.4.9better-auth1.6.23react-router8.2.0@polar-sh/sdk0.48.1@neondatabase/serverless1.1.0

Type-checked against the real SDKs, migration applied to a live Postgres (Neon), connection clients load-tested, then tracked for upstream drift and re-verified when it moves. How we verify

request path
Browserrequest
fetch
React Router v8routing + proxy
verify
Better Authsession
query
Postgres (Neon)pooled

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

What you're getting

React Router v8

React Router v8 (framework mode) — SSR, config/file routes under app/, loaders/actions, and resource routes for API endpoints.

Postgres (Neon)

Postgres on Neon via Drizzle ORM and the postgres-js driver.

Better Auth

Better Auth — self-hosted auth running inside your app against your Postgres (Drizzle adapter).

SaaS

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

Setup

bun add react-router react react-dom drizzle-orm postgres better-auth
DATABASE_URLNeon pooled (-pooler) connection string
BETTER_AUTH_SECRETgenerate with `openssl rand -base64 32`
BETTER_AUTH_URLyour app's base URL

Apply the schema with bunx drizzle-kit push

Initialization

Database client

app/lib/db.ts
import { drizzle } from "drizzle-orm/postgres-js";
import postgres from "postgres";

// Neon pooled endpoint = PgBouncer transaction mode → prepared statements off.
// ponytail: single module-level client; the serverless runtime + PgBouncer do
// the pooling, so no custom pool/globalThis singleton dance needed.
const client = postgres(process.env.DATABASE_URL!, { prepare: false });

export const db = drizzle({ client });
import { boolean, pgTable, text, timestamp } from "drizzle-orm/pg-core";

export const user = pgTable("user", {
  id: text("id").primaryKey(),
  name: text("name").notNull(),
  email: text("email").notNull().unique(),
  emailVerified: boolean("email_verified").notNull().default(false),
  image: text("image"),
  createdAt: timestamp("created_at").notNull().defaultNow(),
  updatedAt: timestamp("updated_at").notNull().defaultNow(),
});

export const session = pgTable("session", {
  id: text("id").primaryKey(),
  expiresAt: timestamp("expires_at").notNull(),
  token: text("token").notNull().unique(),
  createdAt: timestamp("created_at").notNull().defaultNow(),
  updatedAt: timestamp("updated_at").notNull(),
  ipAddress: text("ip_address"),
  userAgent: text("user_agent"),
  userId: text("user_id")
    .notNull()
    .references(() => user.id, { onDelete: "cascade" }),
});

export const account = pgTable("account", {
  id: text("id").primaryKey(),
  accountId: text("account_id").notNull(),
  providerId: text("provider_id").notNull(),
  userId: text("user_id")
    .notNull()
    .references(() => user.id, { onDelete: "cascade" }),
  accessToken: text("access_token"),
  refreshToken: text("refresh_token"),
  idToken: text("id_token"),
  accessTokenExpiresAt: timestamp("access_token_expires_at"),
  refreshTokenExpiresAt: timestamp("refresh_token_expires_at"),
  scope: text("scope"),
  password: text("password"),
  createdAt: timestamp("created_at").notNull().defaultNow(),
  updatedAt: timestamp("updated_at").notNull(),
});

export const verification = pgTable("verification", {
  id: text("id").primaryKey(),
  identifier: text("identifier").notNull(),
  value: text("value").notNull(),
  expiresAt: timestamp("expires_at").notNull(),
  createdAt: timestamp("created_at").notNull().defaultNow(),
  updatedAt: timestamp("updated_at").notNull().defaultNow(),
});
// Better Auth instance (self-hosted, React Router v8).
import { betterAuth } from "better-auth";
import { drizzleAdapter } from "better-auth/adapters/drizzle";
// Reuse the SAME postgres-js/Drizzle client the db slice exported in
// app/lib/db.ts — Better Auth shares the pooled `DATABASE_URL` connection.
import { db } from "./db";
import * as authSchema from "@/db/auth-schema";

export const auth = betterAuth({
  // Drizzle adapter over the shared client. The schema is passed HERE (not into
  // drizzle()) — it is the only consumer that needs it, so the db client stays
  // schema-less. ponytail: do NOT enable experimental.joins; it is the one option
  // that would make the adapter reach into db._.fullSchema.
  // ponytail: usePlural stays false (the default) — with it true Better Auth would
  // look for `sessions`/`accounts` and could bind to the analytics/ledger app-type tables.
  database: drizzleAdapter(db, { provider: "pg", schema: authSchema }),
  // ponytail: email+password is the shortest real auth that works out of
  // the box — add socialProviders / plugins here when the app needs them.
  emailAndPassword: { enabled: true },
  secret: process.env.BETTER_AUTH_SECRET,
  baseURL: process.env.BETTER_AUTH_URL,
});

export type Session = typeof auth.$Infer.Session;
// Better Auth mounted as a React Router resource route (a route module with NO
// default component). auth.handler is framework-agnostic — (Request) => Response —
// so the GET loader and the POST/etc. action both delegate straight to it. The
// `$` splat catches every /api/auth/* sub-path Better Auth routes internally.
import type { LoaderFunctionArgs, ActionFunctionArgs } from "react-router";
import { auth } from "@/lib/auth";

export function loader({ request }: LoaderFunctionArgs) {
  return auth.handler(request);
}

export function action({ request }: ActionFunctionArgs) {
  return auth.handler(request);
}
// Session gate — the RR7 replacement for Next's Edge proxy. Protected loaders
// call `await requireAuth(request)`. Unlike the proxy's cookie-existence check,
// this does the REAL server-side validation via auth.api.getSession, then throws
// a redirect Response (React Router short-circuits the loader on a thrown Response)
// to bounce logged-out users before the protected data ever loads.
import { redirect } from "react-router";
import { auth } from "@/lib/auth";

export async function requireAuth(request: Request) {
  const session = await auth.api.getSession({ headers: request.headers });
  if (!session) {
    throw redirect("/sign-in");
  }
  return session;
}

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: app/db/schema.ts ===
import { relations, sql } from "drizzle-orm";
import {
  bigint,
  check,
  index,
  integer,
  pgTable,
  text,
  timestamp,
  unique,
  uuid,
} from "drizzle-orm/pg-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 = pgTable(
  "organizations",
  {
    id: uuid("id").primaryKey().defaultRandom(),
    slug: text("slug").notNull().unique(),
    name: text("name").notNull(),
    createdAt: timestamp("created_at", { withTimezone: true })
      .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 = pgTable(
  "memberships",
  {
    id: uuid("id").primaryKey().defaultRandom(),
    organizationId: uuid("organization_id")
      .notNull()
      .references(() => organizations.id, { onDelete: "cascade" }),
    // Better Auth's user.id is text — match it, don't recast.
    userId: text("user_id")
      .notNull()
      .references(() => user.id, { onDelete: "cascade" }),
    role: text("role").$type<MemberRole>().notNull().default("member"),
    createdAt: timestamp("created_at", { withTimezone: true })
      .notNull()
      .defaultNow(),
  },
  (t) => [
    unique("memberships_org_user_unique").on(t.organizationId, t.userId),
    index("idx_membership_user").on(t.userId),
    check(
      "memberships_role_check",
      sql`${t.role} in ('owner','admin','member')`,
    ),
  ],
);

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

/** Append-only credit/token meter. Roll up by org+window for quota + billing. */
export const apiUsage = pgTable(
  "api_usage",
  {
    id: uuid("id").primaryKey().defaultRandom(),
    organizationId: uuid("organization_id")
      .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", { withTimezone: true })
      .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.
app/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. The staleness guard
// lives in the UPDATE's WHERE clause, so Postgres' row lock serializes concurrent
// retries (a stale/older event matches no row); brand-new rows insert with
// onConflictDoNothing (race-safe). 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
  // across the app's exact client type.
  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)),
      ),
    )
    .returning({ id: subscriptions.id });
  if (updated.length > 0) return { changed: true };

  // No row updated: 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 };

  const inserted = await db
    .insert(subscriptions)
    .values({
      organizationId: sub.metadata.organizationId,
      planId: sub.metadata.planId,
      status,
      currentPeriodEnd,
      providerSubId: sub.id,
      providerEventAt: eventAt,
    })
    .onConflictDoNothing({ target: subscriptions.providerSubId })
    .returning({ id: subscriptions.id });

  return { changed: inserted.length > 0 };
}
// Polar webhook for React Router v8 (resource route). React Router invokes `action`
// on POST; it 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 type { ActionFunctionArgs } from "react-router";
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 action({ request }: ActionFunctionArgs): 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 isolation

✓ Proven at the database: with the tenant context set to one org, queries return zero of another org's rows (Postgres RLS, FORCEd so even the table owner is bound).
migrations/rls.sql
-- IMPORTANT: RLS is bypassed by the table owner (unless FORCEd) and ALWAYS by
-- BYPASSRLS / superuser roles. Neon's default neondb_owner role has BYPASSRLS, so
-- connecting your app as neondb_owner makes RLS SILENTLY INERT. Create a dedicated
-- non-BYPASSRLS role and point your app's DATABASE_URL at it:
DO $$ BEGIN
  IF NOT EXISTS (SELECT FROM pg_roles WHERE rolname = 'app_tenant') THEN
    CREATE ROLE app_tenant NOLOGIN NOBYPASSRLS;
  END IF;
END $$;
-- Grant LOGIN + a password OUT OF BAND (never in committed SQL), then point DATABASE_URL at it:
--   ALTER ROLE app_tenant LOGIN PASSWORD '<generated>';
GRANT USAGE ON SCHEMA public TO app_tenant;
GRANT SELECT, INSERT, UPDATE, DELETE ON ALL TABLES IN SCHEMA public TO app_tenant;
-- Future tables stay covered (the one-time GRANT above only sees today's tables):
ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT SELECT, INSERT, UPDATE, DELETE ON TABLES TO app_tenant;

-- Tenant isolation via Row-Level Security (FORCE = even the table owner is bound). The shared `plans` catalog is intentionally left open.

ALTER TABLE organizations ENABLE ROW LEVEL SECURITY;
ALTER TABLE organizations FORCE ROW LEVEL SECURITY;
CREATE POLICY organizations_tenant_isolation ON organizations
  USING (id = current_setting('app.current_org_id', true)::uuid)
  WITH CHECK (id = current_setting('app.current_org_id', true)::uuid);

ALTER TABLE memberships ENABLE ROW LEVEL SECURITY;
ALTER TABLE memberships FORCE ROW LEVEL SECURITY;
CREATE POLICY memberships_tenant_isolation ON memberships
  USING (organization_id = current_setting('app.current_org_id', true)::uuid)
  WITH CHECK (organization_id = current_setting('app.current_org_id', true)::uuid);

ALTER TABLE subscriptions ENABLE ROW LEVEL SECURITY;
ALTER TABLE subscriptions FORCE ROW LEVEL SECURITY;
CREATE POLICY subscriptions_tenant_isolation ON subscriptions
  USING (organization_id = current_setting('app.current_org_id', true)::uuid)
  WITH CHECK (organization_id = current_setting('app.current_org_id', true)::uuid);

ALTER TABLE api_usage ENABLE ROW LEVEL SECURITY;
ALTER TABLE api_usage FORCE ROW LEVEL SECURITY;
CREATE POLICY api_usage_tenant_isolation ON api_usage
  USING (organization_id = current_setting('app.current_org_id', true)::uuid)
  WITH CHECK (organization_id = current_setting('app.current_org_id', true)::uuid);
import { sql } from "drizzle-orm";

// Run queries with the tenant context set for THIS transaction. RLS policies read
// app.current_org_id; unset => fail-closed (no rows). Wrap every request's data
// access in withTenant(db, session.orgId, (tx) => ...).
export async function withTenant<T>(
  db: { transaction: (fn: (tx: any) => Promise<T>) => Promise<T> },
  orgId: string,
  fn: (tx: any) => Promise<T>,
): Promise<T> {
  return db.transaction(async (tx) => {
    await tx.execute(sql`select set_config('app.current_org_id', ${orgId}, true)`);
    return fn(tx);
  });
}

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/postgres-js";
import postgres from "postgres";

// Serverless: one connection per (short-lived) instance; Neon's pooler multiplexes.
export const sql = postgres(process.env.DATABASE_URL!, { prepare: false, max: 1 });
export const db = drizzle(sql);
import { drizzle } from "drizzle-orm/postgres-js";
import postgres from "postgres";

// Long-running process: a real, reused pool. Still prepare:false on the pooled endpoint.
export const sql = postgres(process.env.DATABASE_URL!, { prepare: false, max: 10, idle_timeout: 20 });
export const db = drizzle(sql);
import { neon } from "@neondatabase/serverless";
import { drizzle } from "drizzle-orm/neon-http";

// Edge/Workers have NO TCP sockets, so postgres-js cannot run here. Neon's HTTP
// driver speaks Postgres over fetch — the only client that works on Workers.
export const sql = neon(process.env.DATABASE_URL!);
export const db = drizzle(sql);

Decisions and compatibility

note

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).

note

prepare: false is mandatory — Neon's pooled endpoint is PgBouncer in transaction mode, where server-side prepared statements break across the pool.

note

Drizzle is paired here (not Prisma): Prisma's prepared-statement reliance is incompatible with transaction-mode pooling.

note

Self-hosted: Better Auth owns the user/session/account/verification tables. This stack emits them (db/auth-schema.ts) and hands them to the Drizzle adapter, so app-type schemas can foreign-key `user` directly.

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.