diff --git a/products/02-iac-drift-detection/saas/src/auth/middleware.ts b/products/02-iac-drift-detection/saas/src/auth/middleware.ts
new file mode 100644
index 0000000..46a0617
--- /dev/null
+++ b/products/02-iac-drift-detection/saas/src/auth/middleware.ts
@@ -0,0 +1,224 @@
+import { z } from 'zod';
+import jwt from 'jsonwebtoken';
+import crypto from 'node:crypto';
+import type { FastifyInstance, FastifyRequest, FastifyReply } from 'fastify';
+import type { Pool } from 'pg';
+import pino from 'pino';
+
+const logger = pino({ name: 'auth' });
+
+export interface AuthPayload {
+  tenantId: string;
+  userId: string;
+  email: string;
+  role: 'owner' | 'admin' | 'member' | 'viewer';
+}
+
+/**
+ * JWT auth middleware. Extracts tenant context from Bearer token.
+ * Also supports API key auth via `X-API-Key` header (dd0c_ prefix).
+ */
+export function registerAuth(app: FastifyInstance, jwtSecret: string, pool: Pool) {
+  app.decorateRequest('tenantId', '');
+  app.decorateRequest('userId', '');
+  app.decorateRequest('userRole', 'viewer');
+
+  app.addHook('onRequest', async (req: FastifyRequest, reply: FastifyReply) => {
+    if (req.url === '/health') return;
+    if (req.url.startsWith('/webhooks/')) return;
+    if (req.url.startsWith('/slack/')) return;
+    if (req.url.startsWith('/api/v1/auth/login') || req.url.startsWith('/api/v1/auth/signup')) return;
+
+    const apiKey = req.headers['x-api-key'] as string | undefined;
+    const authHeader = req.headers['authorization'];
+
+    if (apiKey) {
+      if (!apiKey.startsWith('dd0c_') || apiKey.length !== 37) {
+        return reply.status(401).send({ error: 'Invalid API key format' });
+      }
+
+      const prefix = apiKey.slice(0, 13); // dd0c_ + 8 hex chars
+      const keyHash = crypto.createHash('sha256').update(apiKey).digest('hex');
+
+      const result = await pool.query(
+        `SELECT ak.tenant_id, ak.user_id, u.role
+         FROM api_keys ak JOIN users u ON ak.user_id = u.id
+         WHERE ak.key_prefix = $1 AND ak.key_hash = $2 AND ak.revoked = false`,
+        [prefix, keyHash],
+      );
+
+      if (!result.rows[0]) {
+        return reply.status(401).send({ error: 'Invalid API key' });
+      }
+
+      (req as any).tenantId = result.rows[0].tenant_id;
+      (req as any).userId = result.rows[0].user_id;
+      (req as any).userRole = result.rows[0].role;
+      return;
+    }
+
+    if (authHeader?.startsWith('Bearer ')) {
+      const token = authHeader.slice(7);
+      try {
+        const payload = jwt.verify(token, jwtSecret) as AuthPayload;
+        (req as any).tenantId = payload.tenantId;
+        (req as any).userId = payload.userId;
+        (req as any).userRole = payload.role;
+        return;
+      } catch {
+        return reply.status(401).send({ error: 'Invalid or expired token' });
+      }
+    }
+
+    return reply.status(401).send({ error: 'Missing authentication' });
+  });
+}
+
+export function requireRole(req: FastifyRequest, reply: FastifyReply, minRole: AuthPayload['role']): boolean {
+  const hierarchy: Record<string, number> = { owner: 4, admin: 3, member: 2, viewer: 1 };
+  const userLevel = hierarchy[(req as any).userRole] ?? 0;
+  const requiredLevel = hierarchy[minRole] ?? 0;
+
+  if (userLevel < requiredLevel) {
+    reply.status(403).send({ error: `Requires ${minRole} role or higher` });
+    return false;
+  }
+  return true;
+}
+
+export function signToken(payload: AuthPayload, secret: string, expiresIn = '24h'): string {
+  return jwt.sign(payload, secret, { expiresIn } as jwt.SignOptions);
+}
+
+// --- Password hashing (scrypt — no native bcrypt dep needed) ---
+
+async function hashPassword(password: string): Promise<string> {
+  const salt = crypto.randomBytes(16).toString('hex');
+  return new Promise((resolve, reject) => {
+    crypto.scrypt(password, salt, 64, (err, derived) => {
+      if (err) reject(err);
+      resolve(`${salt}:${derived.toString('hex')}`);
+    });
+  });
+}
+
+async function verifyPassword(password: string, hash: string): Promise<boolean> {
+  const [salt, key] = hash.split(':');
+  return new Promise((resolve, reject) => {
+    crypto.scrypt(password, salt, 64, (err, derived) => {
+      if (err) reject(err);
+      resolve(crypto.timingSafeEqual(Buffer.from(key, 'hex'), derived));
+    });
+  });
+}
+
+// --- Auth Routes ---
+
+const loginSchema = z.object({
+  email: z.string().email(),
+  password: z.string().min(8),
+});
+
+const signupSchema = z.object({
+  email: z.string().email(),
+  password: z.string().min(8),
+  tenant_name: z.string().min(1).max(100),
+});
+
+export function registerAuthRoutes(app: FastifyInstance, jwtSecret: string, pool: Pool) {
+  app.post('/api/v1/auth/login', async (req, reply) => {
+    const body = loginSchema.parse(req.body);
+
+    const result = await pool.query(
+      `SELECT u.id, u.tenant_id, u.email, u.password_hash, u.role
+       FROM users u WHERE u.email = $1`,
+      [body.email],
+    );
+
+    const user = result.rows[0];
+    if (!user) return reply.status(401).send({ error: 'Invalid credentials' });
+
+    const valid = await verifyPassword(body.password, user.password_hash);
+    if (!valid) return reply.status(401).send({ error: 'Invalid credentials' });
+
+    const token = signToken({
+      tenantId: user.tenant_id,
+      userId: user.id,
+      email: user.email,
+      role: user.role,
+    }, jwtSecret);
+
+    return { token, expires_in: '24h' };
+  });
+
+  app.post('/api/v1/auth/signup', async (req, reply) => {
+    const body = signupSchema.parse(req.body);
+
+    // Check if email already exists
+    const existing = await pool.query('SELECT id FROM users WHERE email = $1', [body.email]);
+    if (existing.rows[0]) return reply.status(409).send({ error: 'Email already registered' });
+
+    const passwordHash = await hashPassword(body.password);
+    const slug = body.tenant_name.toLowerCase().replace(/[^a-z0-9]+/g, '-').slice(0, 50);
+
+    const client = await pool.connect();
+    try {
+      await client.query('BEGIN');
+
+      const tenant = await client.query(
+        `INSERT INTO tenants (name, slug) VALUES ($1, $2) RETURNING id`,
+        [body.tenant_name, slug],
+      );
+      const tenantId = tenant.rows[0].id;
+
+      const user = await client.query(
+        `INSERT INTO users (tenant_id, email, password_hash, role) VALUES ($1, $2, $3, 'owner') RETURNING id`,
+        [tenantId, body.email, passwordHash],
+      );
+
+      await client.query('COMMIT');
+
+      const token = signToken({
+        tenantId,
+        userId: user.rows[0].id,
+        email: body.email,
+        role: 'owner',
+      }, jwtSecret);
+
+      return reply.status(201).send({ token, tenant_id: tenantId, expires_in: '24h' });
+    } catch (err) {
+      await client.query('ROLLBACK');
+      throw err;
+    } finally {
+      client.release();
+    }
+  });
+
+  app.get('/api/v1/auth/me', async (req, reply) => {
+    return {
+      tenant_id: (req as any).tenantId,
+      user_id: (req as any).userId,
+      role: (req as any).userRole,
+    };
+  });
+
+  // Generate API key
+  app.post('/api/v1/auth/api-keys', async (req, reply) => {
+    const tenantId = (req as any).tenantId;
+    const userId = (req as any).userId;
+
+    if (!requireRole(req, reply, 'admin')) return;
+
+    const rawKey = `dd0c_${crypto.randomBytes(16).toString('hex')}`;
+    const prefix = rawKey.slice(0, 13);
+    const keyHash = crypto.createHash('sha256').update(rawKey).digest('hex');
+
+    await pool.query(
+      `INSERT INTO api_keys (tenant_id, user_id, key_prefix, key_hash) VALUES ($1, $2, $3, $4)`,
+      [tenantId, userId, prefix, keyHash],
+    );
+
+    // Return the raw key ONCE — it's never stored or retrievable again
+    return reply.status(201).send({ api_key: rawKey, prefix });
+  });
+}
diff --git a/products/02-iac-drift-detection/saas/src/index.ts b/products/02-iac-drift-detection/saas/src/index.ts
index 6c83ab4..f198255 100644
--- a/products/02-iac-drift-detection/saas/src/index.ts
+++ b/products/02-iac-drift-detection/saas/src/index.ts
@@ -4,15 +4,13 @@ import helmet from '@fastify/helmet';
 import { config } from './config/index.js';
 import { registerProcessorRoutes } from './processor/routes.js';
 import { registerApiRoutes } from './api/routes.js';
+import { registerAuth, registerAuthRoutes } from './auth/middleware.js';
 import { createPool } from './data/db.js';
 import { createRedis } from './data/redis.js';
 
 const app = Fastify({
   logger: {
     level: config.logLevel,
-    transport: config.nodeEnv === 'development'
-      ? { target: 'pino-pretty' }
-      : undefined,
   },
 });
 
@@ -29,13 +27,19 @@ async function start() {
   app.decorate('redis', redis);
   app.decorate('config', config);
 
+  // Auth
+  registerAuth(app, config.jwtSecret, pool);
+
+  // Health (before auth)
+  app.get('/health', async () => ({ status: 'ok' }));
+
+  // Auth routes (signup/login)
+  registerAuthRoutes(app, config.jwtSecret, pool);
+
   // Routes
   await registerProcessorRoutes(app);
   await registerApiRoutes(app);
 
-  // Health
-  app.get('/health', async () => ({ status: 'ok' }));
-
   await app.listen({ port: config.port, host: '0.0.0.0' });
   app.log.info(`dd0c/drift SaaS listening on :${config.port}`);
 }