diff --git a/apps/api/src/http/errors/errorMiddleware.test.ts b/apps/api/src/http/errors/errorMiddleware.test.ts
index a107405..6ce135c 100644
--- a/apps/api/src/http/errors/errorMiddleware.test.ts
+++ b/apps/api/src/http/errors/errorMiddleware.test.ts
@@ -74,6 +74,22 @@ describe('errorMiddleware', () => {
     })
   })
 
+  it.each(['P2021', 'P2022'])('normalizes Prisma schema mismatch errors for %s', (code) => {
+    const spy = vi.spyOn(console, 'error').mockImplementation(() => undefined)
+
+    const res = handle({ code })
+
+    expect(res.status).toHaveBeenCalledWith(503)
+    expect(res.json).toHaveBeenCalledWith({
+      error: 'database_schema_mismatch',
+      message: 'Database schema is out of date. Run database migrations and retry.',
+      statusCode: 503,
+      requestId: undefined,
+    })
+
+    spy.mockRestore()
+  })
+
   it('preserves AppError metadata in the response body', () => {
     const res = handle(new AppError('Plan required', 402, 'payment_required', { requiredPlan: 'PRO' }))
 
diff --git a/apps/api/src/http/errors/errorMiddleware.ts b/apps/api/src/http/errors/errorMiddleware.ts
index 051d91b..cb61ba2 100644
--- a/apps/api/src/http/errors/errorMiddleware.ts
+++ b/apps/api/src/http/errors/errorMiddleware.ts
@@ -23,6 +23,15 @@ export function errorMiddleware(err: any, req: Request, res: Response, _next: Ne
     return res.status(409).json(withRequestId(req, { error: 'conflict', message: 'A resource with this value already exists', statusCode: 409 }))
   }
 
+  if (err.code === 'P2021' || err.code === 'P2022') {
+    console.error('[API Error] Database schema mismatch', { requestId: req.requestId, err })
+    return res.status(503).json(withRequestId(req, {
+      error: 'database_schema_mismatch',
+      message: 'Database schema is out of date. Run database migrations and retry.',
+      statusCode: 503,
+    }))
+  }
+
   if (err instanceof AppError) {
     if (err.statusCode >= 500) console.error('[API Error]', { requestId: req.requestId, err })
     return res.status(err.statusCode).json(withRequestId(req, {
diff --git a/apps/api/src/tests/api/auth-boundaries.api.test.ts b/apps/api/src/tests/api/auth-boundaries.api.test.ts
index 9f0296f..261a703 100644
--- a/apps/api/src/tests/api/auth-boundaries.api.test.ts
+++ b/apps/api/src/tests/api/auth-boundaries.api.test.ts
@@ -29,6 +29,10 @@ vi.mock('../../modules/auth/auth.company.service', () => ({
   }),
 }))
 
+vi.mock('../../modules/auth/auth.account.service', () => ({
+  startAccount: vi.fn(),
+}))
+
 vi.mock('../../modules/auth/auth.renter.service', () => ({
   signupDisabled: vi.fn(() => {
     const err = new Error('renter disabled') as Error & { statusCode?: number; code?: string }
@@ -49,6 +53,7 @@ vi.mock('../../modules/auth/auth.renter.service', () => ({
 
 import request from 'supertest'
 import { createApp } from '../../app'
+import * as accountService from '../../modules/auth/auth.account.service'
 import * as companyService from '../../modules/auth/auth.company.service'
 import * as renterService from '../../modules/auth/auth.renter.service'
 
@@ -90,6 +95,10 @@ const signupPayload = {
 describe('auth API boundaries', () => {
   beforeEach(() => {
     vi.clearAllMocks()
+    vi.mocked(accountService.startAccount).mockResolvedValue({
+      message: 'Account created. Please check your email to verify your address before signing in.',
+      email: 'owner@example.com',
+    } as never)
     vi.mocked(companyService.signup).mockResolvedValue({ companyId: 'company_1', nextStep: 'workspace_created' } as never)
     vi.mocked(renterService.getMe).mockResolvedValue({ id: 'renter_1', savedCompanies: [] } as never)
     vi.mocked(renterService.updateMe).mockResolvedValue({ id: 'renter_1', firstName: 'Nora' } as never)
@@ -117,6 +126,38 @@ describe('auth API boundaries', () => {
     expect(companyService.signup).not.toHaveBeenCalled()
   })
 
+  it('POST /auth/account/start validates minimal signup and returns 201', async () => {
+    const res = await request(app).post('/api/v1/auth/account/start').send({
+      email: 'owner@example.com',
+      password: 'super-secret',
+      preferredLanguage: 'fr',
+    })
+
+    expect(res.status).toBe(201)
+    expect(res.body).toEqual({
+      data: {
+        message: 'Account created. Please check your email to verify your address before signing in.',
+        email: 'owner@example.com',
+      },
+    })
+    expect(accountService.startAccount).toHaveBeenCalledWith({
+      email: 'owner@example.com',
+      password: 'super-secret',
+      preferredLanguage: 'fr',
+    })
+  })
+
+  it('POST /auth/account/start rejects malformed minimal signup payloads before service execution', async () => {
+    const res = await request(app).post('/api/v1/auth/account/start').send({
+      email: 'not-email',
+      password: 'short',
+    })
+
+    expect(res.status).toBe(400)
+    expect(res.body.error).toBe('validation_error')
+    expect(accountService.startAccount).not.toHaveBeenCalled()
+  })
+
   it('preserves removed company auth compatibility endpoints as explicit 410 responses', async () => {
     const complete = await request(app).post('/api/v1/auth/company/complete-signup').send({})
     const verify = await request(app).post('/api/v1/auth/company/verify-email').send({})