diff --git a/apps/hq/src/api.ts b/apps/hq/src/api.ts
index 06fa091..1e671f4 100644
--- a/apps/hq/src/api.ts
+++ b/apps/hq/src/api.ts
@@ -19,6 +19,10 @@ import {
 import {
   clientLedger, modulePaidView, recordPayment, type RecordPaymentInput,
 } from './repos-payments'
+import {
+  createRecurringPlan, deactivateRecurringPlan, getRecurringPlan, listRecurringPlans,
+  updateRecurringPlan, type CreateRecurringInput, type RecurringPatch,
+} from './repos-recurring'
 import { documentHtml } from './templates'
 import { renderPdf } from './pdf'
 import { emailStatus } from './repos-email'
@@ -289,6 +293,38 @@ export function apiRouter(db: DB, gmailDeps?: Partial<GmailDeps>): Router {
     })()
   })
 
+  // ---------- recurring plans ----------
+  r.get('/recurring', requireAuth, (req, res) => {
+    const clientId = typeof req.query['clientId'] === 'string' ? req.query['clientId'] : undefined
+    res.json({ ok: true, plans: listRecurringPlans(db, clientId) })
+  })
+  r.post('/clients/:id/recurring', requireAuth, requireOwner, (req, res) => {
+    const id = String(req.params['id'] ?? '')
+    if (getClient(db, id) === null) { res.status(404).json({ ok: false, error: 'Client not found' }); return }
+    try {
+      const plan = createRecurringPlan(db, staffId(res), {
+        ...(req.body as Omit<CreateRecurringInput, 'clientId'>), clientId: id,
+      })
+      res.json({ ok: true, plan })
+    } catch (err) {
+      res.status(400).json({ ok: false, error: err instanceof Error ? err.message : String(err) })
+    }
+  })
+  r.patch('/recurring/:id', requireAuth, requireOwner, (req, res) => {
+    const id = String(req.params['id'] ?? '')
+    if (getRecurringPlan(db, id) === null) { res.status(404).json({ ok: false, error: 'Recurring plan not found' }); return }
+    try {
+      res.json({ ok: true, plan: updateRecurringPlan(db, staffId(res), id, req.body as RecurringPatch) })
+    } catch (err) {
+      res.status(400).json({ ok: false, error: err instanceof Error ? err.message : String(err) })
+    }
+  })
+  r.post('/recurring/:id/deactivate', requireAuth, requireOwner, (req, res) => {
+    const id = String(req.params['id'] ?? '')
+    if (getRecurringPlan(db, id) === null) { res.status(404).json({ ok: false, error: 'Recurring plan not found' }); return }
+    res.json({ ok: true, plan: deactivateRecurringPlan(db, staffId(res), id) })
+  })
+
   // ---------- payments ----------
   r.post('/payments', requireAuth, (req, res) => {
     try {
diff --git a/apps/hq/src/repos-recurring.ts b/apps/hq/src/repos-recurring.ts
new file mode 100644
index 0000000..dfecaa2
--- /dev/null
+++ b/apps/hq/src/repos-recurring.ts
@@ -0,0 +1,101 @@
+import { uuidv7 } from '@sims/domain'
+import { writeAudit } from './audit'
+import type { DB } from './db'
+import { getClient } from './repos-clients'
+import { getClientModule, priceOn, type Kind } from './repos-modules'
+
+/** Recurring billing plans — plain functions over the handle (D12 portable-repo pattern). */
+
+export type Cadence = 'monthly' | 'yearly'
+export const CADENCE_KIND: Record<Cadence, Kind> = { monthly: 'monthly', yearly: 'yearly' }
+
+export interface RecurringPlan {
+  id: string; clientId: string; clientModuleId: string | null; cadence: Cadence
+  amountPaise: number | null; nextRun: string; policy: 'auto' | 'manual'; active: boolean
+}
+
+interface RecurringRow {
+  id: string; client_id: string; client_module_id: string | null; cadence: string
+  amount_paise: number | null; next_run: string; policy: string; active: number
+}
+
+function toPlan(r: RecurringRow): RecurringPlan {
+  return {
+    id: r.id, clientId: r.client_id, clientModuleId: r.client_module_id,
+    cadence: r.cadence as Cadence, amountPaise: r.amount_paise, nextRun: r.next_run,
+    policy: r.policy as 'auto' | 'manual', active: r.active === 1,
+  }
+}
+
+export function getRecurringPlan(db: DB, id: string): RecurringPlan | null {
+  const row = db.prepare(`SELECT * FROM recurring_plan WHERE id=?`).get(id) as RecurringRow | undefined
+  return row === undefined ? null : toPlan(row)
+}
+
+export function listRecurringPlans(db: DB, clientId?: string): RecurringPlan[] {
+  const rows = clientId === undefined
+    ? db.prepare(`SELECT * FROM recurring_plan ORDER BY id DESC`).all() as RecurringRow[]
+    : db.prepare(`SELECT * FROM recurring_plan WHERE client_id=? ORDER BY id DESC`).all(clientId) as RecurringRow[]
+  return rows.map(toPlan)
+}
+
+export interface CreateRecurringInput {
+  clientId: string; clientModuleId: string; cadence: Cadence
+  amountPaise?: number; nextRun: string; policy?: 'auto' | 'manual'
+}
+
+export function createRecurringPlan(db: DB, userId: string, input: CreateRecurringInput): RecurringPlan {
+  if (getClient(db, input.clientId) === null) throw new Error('Client not found')
+  const cm = getClientModule(db, input.clientModuleId)
+  if (cm === null) throw new Error('Client module not found')
+  if (cm.clientId !== input.clientId) throw new Error('Client module belongs to another client')
+  if (input.amountPaise !== undefined && (!Number.isInteger(input.amountPaise) || input.amountPaise < 0)) {
+    throw new Error('amountPaise must be a non-negative integer (paise)')
+  }
+  // A plan must be priceable at generation time: explicit amount, or a resolvable module price.
+  if (input.amountPaise === undefined) {
+    const kind = CADENCE_KIND[input.cadence]
+    if (priceOn(db, cm.moduleId, kind, cm.edition, input.nextRun) === null) {
+      throw new Error(`No ${kind} price for the module on ${input.nextRun}; set an amount or add a price`)
+    }
+  }
+  const id = uuidv7()
+  db.prepare(
+    `INSERT INTO recurring_plan (id, client_id, client_module_id, cadence, amount_paise, next_run, policy, active)
+     VALUES (?, ?, ?, ?, ?, ?, ?, 1)`,
+  ).run(
+    id, input.clientId, input.clientModuleId, input.cadence,
+    input.amountPaise ?? null, input.nextRun, input.policy ?? 'manual',
+  )
+  const plan = getRecurringPlan(db, id)!
+  writeAudit(db, userId, 'create', 'recurring_plan', id, undefined, plan)
+  return plan
+}
+
+export interface RecurringPatch {
+  cadence?: Cadence; amountPaise?: number | null; nextRun?: string
+  policy?: 'auto' | 'manual'; active?: boolean
+}
+
+export function updateRecurringPlan(db: DB, userId: string, id: string, patch: RecurringPatch): RecurringPlan {
+  const before = getRecurringPlan(db, id)
+  if (before === null) throw new Error('Recurring plan not found')
+  const sets: string[] = []
+  const args: unknown[] = []
+  if (patch.cadence !== undefined) { sets.push('cadence=?'); args.push(patch.cadence) }
+  if (patch.amountPaise !== undefined) { sets.push('amount_paise=?'); args.push(patch.amountPaise) }
+  if (patch.nextRun !== undefined) { sets.push('next_run=?'); args.push(patch.nextRun) }
+  if (patch.policy !== undefined) { sets.push('policy=?'); args.push(patch.policy) }
+  if (patch.active !== undefined) { sets.push('active=?'); args.push(patch.active ? 1 : 0) }
+  if (sets.length > 0) {
+    args.push(id)
+    db.prepare(`UPDATE recurring_plan SET ${sets.join(', ')} WHERE id=?`).run(...args)
+  }
+  const after = getRecurringPlan(db, id)!
+  writeAudit(db, userId, 'update', 'recurring_plan', id, before, after)
+  return after
+}
+
+export function deactivateRecurringPlan(db: DB, userId: string, id: string): RecurringPlan {
+  return updateRecurringPlan(db, userId, id, { active: false })
+}
diff --git a/apps/hq/test/recurring.test.ts b/apps/hq/test/recurring.test.ts
new file mode 100644
index 0000000..19f753a
--- /dev/null
+++ b/apps/hq/test/recurring.test.ts
@@ -0,0 +1,50 @@
+import { describe, it, expect } from 'vitest'
+import { openDb } from '../src/db'
+import { createClient } from '../src/repos-clients'
+import { assignModule, createModule, setPrice } from '../src/repos-modules'
+import {
+  createRecurringPlan, listRecurringPlans, updateRecurringPlan, deactivateRecurringPlan,
+} from '../src/repos-recurring'
+
+function setup() {
+  const db = openDb(':memory:')
+  const c = createClient(db, 'u1', { name: 'Acme', stateCode: '32' })
+  const m = createModule(db, 'u1', { code: 'CLOUD', name: 'Cloud Hosting', allowedKinds: ['monthly', 'yearly'] })
+  setPrice(db, 'u1', { moduleId: m.id, kind: 'monthly', pricePaise: 2_000_00, effectiveFrom: '2026-04-01' })
+  const cm = assignModule(db, 'u1', { clientId: c.id, moduleId: m.id, kind: 'monthly' })
+  return { db, c, m, cm }
+}
+
+describe('recurring plans', () => {
+  it('creates a plan, lists it, updates and deactivates with audit', () => {
+    const { db, c, cm } = setup()
+    const p = createRecurringPlan(db, 'u1', {
+      clientId: c.id, clientModuleId: cm.id, cadence: 'monthly', nextRun: '2026-08-01', policy: 'auto',
+    })
+    expect(p.policy).toBe('auto')
+    expect(p.amountPaise).toBeNull() // price resolves from the module at generation
+    expect(listRecurringPlans(db, c.id)).toHaveLength(1)
+    const up = updateRecurringPlan(db, 'u1', p.id, { amountPaise: 2_500_00 })
+    expect(up.amountPaise).toBe(2_500_00)
+    const off = deactivateRecurringPlan(db, 'u1', p.id)
+    expect(off.active).toBe(false)
+    const audits = db.prepare(`SELECT action FROM audit_log WHERE entity='recurring_plan'`).all()
+    expect(audits.length).toBe(3) // create + update + deactivate
+  })
+  it('rejects a plan whose module has no price and no explicit amount', () => {
+    const db = openDb(':memory:')
+    const c = createClient(db, 'u1', { name: 'X', stateCode: '32' })
+    const m = createModule(db, 'u1', { code: 'POS', name: 'POS', allowedKinds: ['yearly'] })
+    const cm = assignModule(db, 'u1', { clientId: c.id, moduleId: m.id, kind: 'yearly' })
+    expect(() => createRecurringPlan(db, 'u1', {
+      clientId: c.id, clientModuleId: cm.id, cadence: 'yearly', nextRun: '2026-08-01',
+    })).toThrow(/price/i)
+  })
+  it('rejects a client_module that belongs to another client', () => {
+    const { db, cm } = setup()
+    const other = createClient(db, 'u1', { name: 'Other', stateCode: '32' })
+    expect(() => createRecurringPlan(db, 'u1', {
+      clientId: other.id, clientModuleId: cm.id, cadence: 'monthly', nextRun: '2026-08-01', amountPaise: 100_00,
+    })).toThrow(/client/i)
+  })
+})