diff --git a/backend/src/controllers/__tests__/authController.test.ts b/backend/src/controllers/__tests__/authController.test.ts
index 95bf97f8..ca446051 100644
--- a/backend/src/controllers/__tests__/authController.test.ts
+++ b/backend/src/controllers/__tests__/authController.test.ts
@@ -16,10 +16,11 @@ import { authenticator } from '@otplib/preset-default';
 jest.setTimeout(30_000);
 
 const mockQuery = jest.fn<any>();
+const mockConnect = jest.fn<any>();
 
 jest.unstable_mockModule('../../config/database.js', () => ({
   query: mockQuery,
-  pool: { query: mockQuery },
+  pool: { query: mockQuery, connect: mockConnect },
   default: { query: mockQuery },
 }));
 
@@ -125,6 +126,48 @@ async function enrol(): Promise<{ secret: string; encrypted: string }> {
 describe('Auth 2FA endpoints', () => {
   beforeEach(() => {
     mockQuery.mockReset();
+    mockConnect.mockReset();
+  });
+
+  describe('POST /api/auth/register', () => {
+    it('consumes a valid invitation and issues an organization-bound session', async () => {
+      const transactionQuery = jest
+        .fn<any>()
+        .mockResolvedValueOnce({ rows: [] }) // BEGIN
+        .mockResolvedValueOnce({ rows: [{ id: 9, organization_id: 1 }] })
+        .mockResolvedValueOnce({ rows: [userRow({ role: 'EMPLOYEE' })] })
+        .mockResolvedValueOnce({ rows: [] }) // consume invitation
+        .mockResolvedValueOnce({ rows: [] }); // COMMIT
+      const release = jest.fn();
+      mockConnect.mockResolvedValue({ query: transactionQuery, release });
+
+      const response = await request(app)
+        .post('/api/auth/register')
+        .send({ walletAddress: 'GNEWEMPLOYEE', invitationToken: 'valid-invitation' });
+
+      expect(response.status).toBe(201);
+      const claims = jwt.verify(response.body.accessToken, config.JWT_SECRET) as any;
+      expect(claims.organizationId).toBe(1);
+      expect(claims.role).toBe('EMPLOYEE');
+      expect(transactionQuery.mock.calls.some((call: any[]) => /used_at = CURRENT_TIMESTAMP/.test(call[0]))).toBe(true);
+      expect(release).toHaveBeenCalled();
+    });
+
+    it('rejects invalid, expired, or previously consumed invitations', async () => {
+      const transactionQuery = jest
+        .fn<any>()
+        .mockResolvedValueOnce({ rows: [] }) // BEGIN
+        .mockResolvedValueOnce({ rows: [] }) // invitation lookup
+        .mockResolvedValueOnce({ rows: [] }); // ROLLBACK
+      mockConnect.mockResolvedValue({ query: transactionQuery, release: jest.fn() });
+
+      const response = await request(app)
+        .post('/api/auth/register')
+        .send({ walletAddress: 'GNEWEMPLOYEE', invitationToken: 'used-invitation' });
+
+      expect(response.status).toBe(403);
+      expect(transactionQuery.mock.calls.some((call: any[]) => /INSERT INTO users/.test(call[0]))).toBe(false);
+    });
   });
 
   describe('POST /api/auth/2fa/setup', () => {
@@ -264,6 +307,18 @@ describe('Auth 2FA endpoints', () => {
 
       expect(response.status).toBe(400);
     });
+
+    it('rejects an unknown wallet without creating an account', async () => {
+      route([SELECT_LOGIN_USER, () => ({ rows: [], rowCount: 0 })]);
+
+      const response = await request(app)
+        .post('/api/auth/login')
+        .send({ walletAddress: 'GUNINVITED' });
+
+      expect(response.status).toBe(403);
+      expect(response.body.error).toMatch(/invitation/i);
+      expect(issuedSql().some((sql) => /INSERT INTO users/i.test(sql))).toBe(false);
+    });
   });
 
   describe('POST /api/auth/2fa/authenticate', () => {
diff --git a/backend/src/controllers/authController.ts b/backend/src/controllers/authController.ts
index 89e25391..5fc95b7d 100644
--- a/backend/src/controllers/authController.ts
+++ b/backend/src/controllers/authController.ts
@@ -1,7 +1,8 @@
 import express from 'express';
+import { createHash, randomBytes } from 'crypto';
 import jwt from 'jsonwebtoken';
 import { config } from '../config/env.js';
-import { query } from '../config/database.js';
+import { pool, query } from '../config/database.js';
 import {
   generateRefreshToken,
   generateToken,
@@ -48,6 +49,89 @@ async function issueSession(user: {
 }
 
 export class AuthController {
+  /**
+   * POST /api/auth/invitations
+   * Creates a single-use employee invitation for the caller's organization.
+   */
+  static async createInvitation(req: express.Request, res: express.Response) {
+    const { email, expiresInDays = 7 } = req.body ?? {};
+    if (email !== undefined && (typeof email !== 'string' || email.length > 255)) {
+      return res.status(400).json({ error: 'Invalid email' });
+    }
+    if (!Number.isInteger(expiresInDays) || expiresInDays < 1 || expiresInDays > 30) {
+      return res.status(400).json({ error: 'expiresInDays must be an integer between 1 and 30' });
+    }
+
+    try {
+      const employer = await query(
+        'SELECT organization_id, role FROM users WHERE id = $1',
+        [req.user!.id]
+      );
+      const user = employer.rows[0];
+      if (!user?.organization_id || user.role !== 'EMPLOYER') {
+        return res.status(403).json({ error: 'Only organization employers can create invitations' });
+      }
+
+      const token = randomBytes(32).toString('base64url');
+      const tokenHash = createHash('sha256').update(token).digest('hex');
+      const expiresAt = new Date(Date.now() + expiresInDays * 24 * 60 * 60 * 1000);
+      const invitation = await query(
+        `INSERT INTO invitations (organization_id, email, token_hash, expires_at, created_by)
+         VALUES ($1, $2, $3, $4, $5) RETURNING id, organization_id, email, expires_at`,
+        [user.organization_id, email ?? null, tokenHash, expiresAt, req.user!.id]
+      );
+
+      // The raw token is only returned at creation time and is never stored.
+      return res.status(201).json({ ...invitation.rows[0], token });
+    } catch (error) {
+      console.error('Invitation creation failed:', error);
+      return res.status(500).json({ error: 'Internal server error' });
+    }
+  }
+
+  /** POST /api/auth/register */
+  static async register(req: express.Request, res: express.Response) {
+    const { walletAddress, invitationToken } = req.body ?? {};
+    if (typeof walletAddress !== 'string' || !walletAddress || typeof invitationToken !== 'string' || !invitationToken) {
+      return res.status(400).json({ error: 'walletAddress and invitationToken are required' });
+    }
+
+    const client = await pool.connect();
+    try {
+      await client.query('BEGIN');
+      const tokenHash = createHash('sha256').update(invitationToken).digest('hex');
+      const invitation = await client.query(
+        `SELECT id, organization_id FROM invitations
+         WHERE token_hash = $1 AND used_at IS NULL AND expires_at > CURRENT_TIMESTAMP FOR UPDATE`,
+        [tokenHash]
+      );
+      if (invitation.rows.length === 0) {
+        await client.query('ROLLBACK');
+        return res.status(403).json({ error: 'Invalid, expired, or already used invitation' });
+      }
+
+      const user = await client.query(
+        `INSERT INTO users (wallet_address, organization_id, role)
+         VALUES ($1, $2, 'EMPLOYEE')
+         RETURNING id, wallet_address, email, organization_id, role`,
+        [walletAddress, invitation.rows[0].organization_id]
+      );
+      await client.query('UPDATE invitations SET used_at = CURRENT_TIMESTAMP WHERE id = $1', [invitation.rows[0].id]);
+      await client.query('COMMIT');
+
+      return res.status(201).json(await issueSession(user.rows[0]));
+    } catch (error: any) {
+      await client.query('ROLLBACK');
+      if (error?.code === '23505') {
+        return res.status(409).json({ error: 'Wallet address is already registered' });
+      }
+      console.error('Invitation registration failed:', error);
+      return res.status(500).json({ error: 'Internal server error' });
+    } finally {
+      client.release();
+    }
+  }
+
   /**
    * POST /api/auth/2fa/setup
    * Starts enrolment for the authenticated admin: mints a secret, stores it as
@@ -190,13 +274,8 @@ export class AuthController {
       );
 
       if (result.rows.length === 0) {
-        // For demo purposes, auto-register as EMPLOYEE if not found
-        // In production, this would be a separate registration flow
-        const insertResult = await query(
-          'INSERT INTO users (wallet_address, role) VALUES ($1, $2) RETURNING *',
-          [walletAddress, 'EMPLOYEE']
-        );
-        return res.json({ accessToken: generateToken(insertResult.rows[0]) });
+        // Account creation must happen through the organization invitation flow.
+        return res.status(403).json({ error: 'An organization invitation is required to register' });
       }
 
       const user = result.rows[0];
diff --git a/backend/src/db/migrations/031_create_invitations.sql b/backend/src/db/migrations/031_create_invitations.sql
new file mode 100644
index 00000000..336ed004
--- /dev/null
+++ b/backend/src/db/migrations/031_create_invitations.sql
@@ -0,0 +1,14 @@
+-- Wallet accounts are created only when an employer-issued invitation is consumed.
+CREATE TABLE IF NOT EXISTS invitations (
+  id SERIAL PRIMARY KEY,
+  organization_id INTEGER NOT NULL REFERENCES organizations(id) ON DELETE CASCADE,
+  email VARCHAR(255),
+  token_hash CHAR(64) NOT NULL UNIQUE,
+  expires_at TIMESTAMP NOT NULL,
+  used_at TIMESTAMP,
+  created_by INTEGER NOT NULL REFERENCES users(id) ON DELETE RESTRICT,
+  created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
+);
+
+CREATE INDEX IF NOT EXISTS idx_invitations_valid_token
+  ON invitations (token_hash, expires_at) WHERE used_at IS NULL;
diff --git a/backend/src/routes/authRoutes.ts b/backend/src/routes/authRoutes.ts
index 9ea8475f..16f75526 100644
--- a/backend/src/routes/authRoutes.ts
+++ b/backend/src/routes/authRoutes.ts
@@ -8,8 +8,16 @@ import { TWO_FACTOR_ROLES } from '../services/twoFactorService.js';
 const router = Router();
 
 router.post('/login', AuthController.login);
+router.post('/register', AuthController.register);
 router.post('/refresh', AuthController.refresh);
 
+router.post(
+  '/invitations',
+  authenticateJWT,
+  authorizeRoles('EMPLOYER'),
+  AuthController.createInvitation
+);
+
 // ── Two-factor authentication ──────────────────────────────────────────────
 //
 // Enrolment endpoints are account settings, so they run on the caller's own