diff --git a/apps/backend/src/repositories/message-delivery-repo.js b/apps/backend/src/repositories/message-delivery-repo.ts
similarity index 65%
rename from apps/backend/src/repositories/message-delivery-repo.js
rename to apps/backend/src/repositories/message-delivery-repo.ts
index 824e7454..0dcd5525 100644
--- a/apps/backend/src/repositories/message-delivery-repo.js
+++ b/apps/backend/src/repositories/message-delivery-repo.ts
@@ -1,7 +1,72 @@
 import { query } from '../db/client.js'
+import type {
+  MessageDeliveryListQueryResult,
+  MessageDeliveryRow,
+} from '../types/repository-rows.js'
 
-export async function createMessageDelivery(input) {
-  const result = await query(
+type MessageDeliveryCreateInput = {
+  provider: string
+  platform: string
+  shopId?: string
+  shopName?: string
+  channel: string
+  orderId?: number | string | null
+  taskId?: number | string | null
+  platformOrderId?: string
+  recipientKey?: string
+  messageContent?: string
+  claimUrl?: string
+  status?: string
+  requestUrl?: string
+  requestHeadersJson?: string | Record<string, unknown>
+  requestBodyJson?: string | Record<string, unknown>
+  responseStatus?: number | string
+  responseJson?: string | Record<string, unknown>
+  errorMessage?: string
+  sentAt?: string | null
+  createdAt: string
+  updatedAt: string
+}
+
+type MessageDeliveryPatch = Partial<Pick<
+  MessageDeliveryRow,
+  | 'status'
+  | 'request_url'
+  | 'request_headers_json'
+  | 'request_body_json'
+  | 'response_status'
+  | 'response_json'
+  | 'error_message'
+  | 'sent_at'
+  | 'updated_at'
+>>
+
+type LatestSuccessfulMessageDeliveryQuery = {
+  provider?: string
+  platform?: string
+  shopId?: string
+  platformOrderId?: string
+  channel?: string
+  claimUrl?: string
+}
+
+type MessageDeliveryListQuery = {
+  page?: number
+  pageSize?: number
+  provider?: string
+  platform?: string
+  status?: string
+  shopId?: string
+  platformOrderId?: string
+  taskNo?: string
+  dateFrom?: string
+  dateTo?: string
+}
+
+export async function createMessageDelivery(
+  input: MessageDeliveryCreateInput,
+): Promise<MessageDeliveryRow | null> {
+  const result = await query<MessageDeliveryRow>(
     `
       INSERT INTO message_deliveries (
         provider,
@@ -56,19 +121,24 @@ export async function createMessageDelivery(input) {
   return result.rows[0] || null
 }
 
-export async function getMessageDeliveryById(deliveryId) {
-  const result = await query('SELECT * FROM message_deliveries WHERE id = $1 LIMIT 1', [Number(deliveryId)])
+export async function getMessageDeliveryById(deliveryId: number | string): Promise<MessageDeliveryRow | null> {
+  const result = await query<MessageDeliveryRow>('SELECT * FROM message_deliveries WHERE id = $1 LIMIT 1', [
+    Number(deliveryId),
+  ])
   return result.rows[0] || null
 }
 
-export async function updateMessageDelivery(deliveryId, patch = {}) {
+export async function updateMessageDelivery(
+  deliveryId: number | string,
+  patch: MessageDeliveryPatch = {},
+): Promise<MessageDeliveryRow | null> {
   const current = await getMessageDeliveryById(deliveryId)
   if (!current) {
     return null
   }
 
   const next = { ...current, ...patch }
-  const result = await query(
+  const result = await query<MessageDeliveryRow>(
     `
       UPDATE message_deliveries
       SET
@@ -101,8 +171,11 @@ export async function updateMessageDelivery(deliveryId, patch = {}) {
   return result.rows[0] || null
 }
 
-export async function findLatestSuccessfulMessageDeliveryByTask(taskId, channel) {
-  const result = await query(
+export async function findLatestSuccessfulMessageDeliveryByTask(
+  taskId: number | string,
+  channel: string,
+): Promise<MessageDeliveryRow | null> {
+  const result = await query<MessageDeliveryRow>(
     `
       SELECT *
       FROM message_deliveries
@@ -123,8 +196,8 @@ export async function findLatestSuccessfulMessageDelivery({
   platformOrderId = '',
   channel = '',
   claimUrl = '',
-} = {}) {
-  const result = await query(
+}: LatestSuccessfulMessageDeliveryQuery = {}): Promise<MessageDeliveryRow | null> {
+  const result = await query<MessageDeliveryRow>(
     `
       SELECT *
       FROM message_deliveries
@@ -162,10 +235,10 @@ export async function listMessageDeliveries({
   taskNo = '',
   dateFrom = '',
   dateTo = '',
-} = {}) {
+}: MessageDeliveryListQuery = {}): Promise<MessageDeliveryListQueryResult> {
   const offset = (page - 1) * pageSize
-  const filters = []
-  const params = []
+  const filters: string[] = []
+  const params: unknown[] = []
 
   if (provider) {
     params.push(provider)
@@ -213,14 +286,14 @@ export async function listMessageDeliveries({
     LEFT JOIN fulfillment_tasks ft ON ft.id = md.task_id
   `
 
-  const totalResult = await query(
+  const totalResult = await query<{ [column: string]: unknown, total: number }>(
     `SELECT COUNT(*)::int AS total ${fromClause} ${whereClause}`,
     params,
   )
 
   params.push(pageSize)
   params.push(offset)
-  const itemsResult = await query(
+  const itemsResult = await query<MessageDeliveryRow>(
     `
       SELECT
         md.*,
diff --git a/apps/backend/src/repositories/order-item-repo.js b/apps/backend/src/repositories/order-item-repo.ts
similarity index 61%
rename from apps/backend/src/repositories/order-item-repo.js
rename to apps/backend/src/repositories/order-item-repo.ts
index 8f30372a..7752dd24 100644
--- a/apps/backend/src/repositories/order-item-repo.js
+++ b/apps/backend/src/repositories/order-item-repo.ts
@@ -1,20 +1,32 @@
-// @ts-check
+import type { PoolClient, QueryResult } from 'pg'
 
 import { query, withTransaction } from '../db/client.js'
+import type { OrderItemReplaceInput } from '../types/repository-inputs.js'
+import type { OrderItemRow } from '../types/repository-rows.js'
 
-/** @typedef {import('../types/repository-inputs.js').OrderItemReplaceInput} OrderItemReplaceInput */
-/** @typedef {import('../types/repository-rows.js').OrderItemRow} OrderItemRow */
+type QueryExecutor = (text: string, params?: unknown[]) => Promise<QueryResult<any>>
 
-/** @returns {Promise<OrderItemRow[]>} */
-export async function listOrderItemsByOrderId(orderId) {
+type OrderItemSyncPlan = {
+  updates: Array<{
+    orderItemId: number
+    item: OrderItemReplaceInput
+  }>
+  creates: OrderItemReplaceInput[]
+  deletes: number[]
+}
+
+type OrderItemIdentityInput = Partial<OrderItemReplaceInput> & Partial<OrderItemRow>
+
+export async function listOrderItemsByOrderId(orderId: number | string): Promise<OrderItemRow[]> {
   return listOrderItemsByOrderIdWithExecutor(query, orderId)
 }
 
-/** @returns {Promise<OrderItemRow[]>} */
-/** @param {OrderItemReplaceInput[]} items */
-export async function replaceOrderItems(orderId, items) {
-  return withTransaction(async (client) => {
-    const executor = client.query.bind(client)
+export async function replaceOrderItems(
+  orderId: number | string,
+  items: OrderItemReplaceInput[],
+): Promise<OrderItemRow[]> {
+  return withTransaction(async (client: PoolClient) => {
+    const executor: QueryExecutor = client.query.bind(client)
     const existingItems = await listOrderItemsByOrderIdWithExecutor(executor, orderId)
     const plan = resolveOrderItemSyncPlan(existingItems, items)
 
@@ -74,10 +86,7 @@ export async function replaceOrderItems(orderId, items) {
       const deletableIds = await listDeletableOrderItemIdsWithExecutor(executor, plan.deletes)
 
       if (deletableIds.length > 0) {
-        await executor(
-          'DELETE FROM order_items WHERE id = ANY($1::bigint[])',
-          [deletableIds],
-        )
+        await executor('DELETE FROM order_items WHERE id = ANY($1::bigint[])', [deletableIds])
       }
     }
 
@@ -85,16 +94,15 @@ export async function replaceOrderItems(orderId, items) {
   })
 }
 
-/**
- * @param {OrderItemRow[]} existingItems
- * @param {OrderItemReplaceInput[]} nextItems
- */
-export function resolveOrderItemSyncPlan(existingItems, nextItems) {
+export function resolveOrderItemSyncPlan(
+  existingItems: OrderItemRow[],
+  nextItems: OrderItemReplaceInput[],
+): OrderItemSyncPlan {
   const normalizedExisting = Array.isArray(existingItems) ? existingItems : []
   const normalizedNext = Array.isArray(nextItems) ? nextItems : []
   const unmatchedExisting = [...normalizedExisting]
-  const updates = []
-  const creates = []
+  const updates: OrderItemSyncPlan['updates'] = []
+  const creates: OrderItemReplaceInput[] = []
 
   for (const item of normalizedNext) {
     const matchedIndex = findMatchingExistingOrderItemIndex(unmatchedExisting, item)
@@ -110,10 +118,12 @@ export function resolveOrderItemSyncPlan(existingItems, nextItems) {
 
     if (unmatchedExisting.length > 0) {
       const matched = unmatchedExisting.shift()
-      updates.push({
-        orderItemId: matched.id,
-        item,
-      })
+      if (matched) {
+        updates.push({
+          orderItemId: matched.id,
+          item,
+        })
+      }
       continue
     }
 
@@ -127,21 +137,27 @@ export function resolveOrderItemSyncPlan(existingItems, nextItems) {
   }
 }
 
-function findMatchingExistingOrderItemIndex(existingItems, nextItem) {
+function findMatchingExistingOrderItemIndex(
+  existingItems: OrderItemRow[],
+  nextItem: OrderItemReplaceInput,
+): number {
   const nextIdentity = buildOrderItemIdentity(nextItem)
 
   return existingItems.findIndex((item) => buildOrderItemIdentity(item) === nextIdentity)
 }
 
-function buildOrderItemIdentity(item) {
+function buildOrderItemIdentity(item: OrderItemIdentityInput): string {
   return [
-    String(item?.skuCode ?? item?.sku_code ?? '').trim(),
-    String(item?.skuName ?? item?.sku_name ?? '').trim(),
-    String(Math.max(1, Number(item?.quantity || 1))),
+    String(item.skuCode ?? item.sku_code ?? '').trim(),
+    String(item.skuName ?? item.sku_name ?? '').trim(),
+    String(Math.max(1, Number(item.quantity || 1))),
   ].join('::')
 }
 
-async function listDeletableOrderItemIdsWithExecutor(executor, orderItemIds) {
+async function listDeletableOrderItemIdsWithExecutor(
+  executor: QueryExecutor,
+  orderItemIds: number[],
+): Promise<number[]> {
   const normalizedIds = Array.isArray(orderItemIds)
     ? orderItemIds.map((value) => Number(value)).filter((value) => value > 0)
     : []
@@ -166,7 +182,10 @@ async function listDeletableOrderItemIdsWithExecutor(executor, orderItemIds) {
   return result.rows.map((row) => Number(row.id)).filter((value) => value > 0)
 }
 
-async function listOrderItemsByOrderIdWithExecutor(executor, orderId) {
+async function listOrderItemsByOrderIdWithExecutor(
+  executor: QueryExecutor,
+  orderId: number | string,
+): Promise<OrderItemRow[]> {
   const result = await executor(
     `
       SELECT *
@@ -177,11 +196,10 @@ async function listOrderItemsByOrderIdWithExecutor(executor, orderId) {
     [Number(orderId)],
   )
 
-  return /** @type {OrderItemRow[]} */ (result.rows)
+  return result.rows
 }
 
-/** @returns {Promise<OrderItemRow | null>} */
-export async function getOrderItemById(orderItemId) {
-  const result = await query('SELECT * FROM order_items WHERE id = $1 LIMIT 1', [Number(orderItemId)])
-  return /** @type {OrderItemRow | null} */ (result.rows[0] || null)
+export async function getOrderItemById(orderItemId: number | string): Promise<OrderItemRow | null> {
+  const result = await query<OrderItemRow>('SELECT * FROM order_items WHERE id = $1 LIMIT 1', [Number(orderItemId)])
+  return result.rows[0] || null
 }
diff --git a/apps/backend/src/repositories/webhook-event-repo.js b/apps/backend/src/repositories/webhook-event-repo.ts
similarity index 62%
rename from apps/backend/src/repositories/webhook-event-repo.js
rename to apps/backend/src/repositories/webhook-event-repo.ts
index 9463363f..4b8220ef 100644
--- a/apps/backend/src/repositories/webhook-event-repo.js
+++ b/apps/backend/src/repositories/webhook-event-repo.ts
@@ -1,17 +1,16 @@
-// @ts-check
-
 import { query } from '../db/client.js'
+import type {
+  WebhookEventCreateInput,
+  WebhookEventListQueryInput,
+  WebhookEventUpdatePatch,
+} from '../types/repository-inputs.js'
+import type {
+  WebhookEventListQueryResult,
+  WebhookEventRow,
+} from '../types/repository-rows.js'
 
-/** @typedef {import('../types/repository-inputs.js').WebhookEventCreateInput} WebhookEventCreateInput */
-/** @typedef {import('../types/repository-inputs.js').WebhookEventListQueryInput} WebhookEventListQueryInput */
-/** @typedef {import('../types/repository-inputs.js').WebhookEventUpdatePatch} WebhookEventUpdatePatch */
-/** @typedef {import('../types/repository-rows.js').WebhookEventListQueryResult} WebhookEventListQueryResult */
-/** @typedef {import('../types/repository-rows.js').WebhookEventRow} WebhookEventRow */
-
-/** @returns {Promise<WebhookEventRow | null>} */
-/** @param {WebhookEventCreateInput} input */
-export async function createWebhookEvent(input) {
-  const result = await query(
+export async function createWebhookEvent(input: WebhookEventCreateInput): Promise<WebhookEventRow | null> {
+  const result = await query<WebhookEventRow>(
     `
       INSERT INTO webhook_events (
         provider,
@@ -49,19 +48,20 @@ export async function createWebhookEvent(input) {
     ],
   )
 
-  return /** @type {WebhookEventRow | null} */ (result.rows[0] || null)
+  return result.rows[0] || null
 }
 
-/** @returns {Promise<WebhookEventRow | null>} */
-/** @param {WebhookEventUpdatePatch} patch */
-export async function updateWebhookEvent(eventId, patch) {
+export async function updateWebhookEvent(
+  eventId: number | string,
+  patch: WebhookEventUpdatePatch,
+): Promise<WebhookEventRow | null> {
   const current = await getWebhookEventById(eventId)
   if (!current) {
     return null
   }
 
   const next = { ...current, ...patch }
-  const result = await query(
+  const result = await query<WebhookEventRow>(
     `
       UPDATE webhook_events
       SET
@@ -74,17 +74,16 @@ export async function updateWebhookEvent(eventId, patch) {
     [Boolean(next.processed), next.process_error || '', next.related_order_id || null, Number(eventId)],
   )
 
-  return /** @type {WebhookEventRow | null} */ (result.rows[0] || null)
+  return result.rows[0] || null
 }
 
-/** @returns {Promise<WebhookEventRow | null>} */
-export async function getWebhookEventById(eventId) {
-  const result = await query('SELECT * FROM webhook_events WHERE id = $1 LIMIT 1', [Number(eventId)])
-  return /** @type {WebhookEventRow | null} */ (result.rows[0] || null)
+export async function getWebhookEventById(eventId: number | string): Promise<WebhookEventRow | null> {
+  const result = await query<WebhookEventRow>('SELECT * FROM webhook_events WHERE id = $1 LIMIT 1', [
+    Number(eventId),
+  ])
+  return result.rows[0] || null
 }
 
-/** @returns {Promise<WebhookEventListQueryResult>} */
-/** @param {WebhookEventListQueryInput} [queryInput] */
 export async function listWebhookEvents({
   page = 1,
   pageSize = 20,
@@ -96,10 +95,10 @@ export async function listWebhookEvents({
   relatedOrderId = '',
   dateFrom = '',
   dateTo = '',
-} = /** @type {WebhookEventListQueryInput} */ ({})) {
+}: WebhookEventListQueryInput = {}): Promise<WebhookEventListQueryResult> {
   const offset = (page - 1) * pageSize
-  const filters = []
-  const params = []
+  const filters: string[] = []
+  const params: unknown[] = []
 
   if (provider) {
     params.push(provider)
@@ -143,11 +142,14 @@ export async function listWebhookEvents({
   }
 
   const whereClause = filters.length > 0 ? `WHERE ${filters.join(' AND ')}` : ''
-  const totalResult = await query(`SELECT COUNT(*)::int AS total FROM webhook_events ${whereClause}`, params)
+  const totalResult = await query<{ [column: string]: unknown, total: number }>(
+    `SELECT COUNT(*)::int AS total FROM webhook_events ${whereClause}`,
+    params,
+  )
 
   params.push(pageSize)
   params.push(offset)
-  const itemsResult = await query(
+  const itemsResult = await query<WebhookEventRow>(
     `
       SELECT *
       FROM webhook_events
@@ -159,14 +161,13 @@ export async function listWebhookEvents({
   )
 
   return {
-    items: /** @type {WebhookEventRow[]} */ (itemsResult.rows),
+    items: itemsResult.rows,
     total: Number(totalResult.rows[0]?.total || 0),
   }
 }
 
-/** @returns {Promise<WebhookEventRow[]>} */
-export async function listWebhookEventsByOrderId(orderId) {
-  const result = await query(
+export async function listWebhookEventsByOrderId(orderId: number | string): Promise<WebhookEventRow[]> {
+  const result = await query<WebhookEventRow>(
     `
       SELECT *
       FROM webhook_events
@@ -176,5 +177,5 @@ export async function listWebhookEventsByOrderId(orderId) {
     [Number(orderId)],
   )
 
-  return /** @type {WebhookEventRow[]} */ (result.rows)
+  return result.rows
 }
diff --git a/apps/backend/src/types/repository-rows.ts b/apps/backend/src/types/repository-rows.ts
index 2fbc2b6c..fbbae5e2 100644
--- a/apps/backend/src/types/repository-rows.ts
+++ b/apps/backend/src/types/repository-rows.ts
@@ -119,6 +119,33 @@ export type WebhookEventRow = {
   created_at: string
 }
 
+export type MessageDeliveryRow = {
+  id: number
+  provider: string
+  platform: string
+  shop_id: string
+  shop_name: string
+  channel: string
+  order_id: number | null
+  task_id: number | null
+  platform_order_id: string
+  recipient_key: string
+  message_content: string
+  claim_url: string
+  status: string
+  request_url: string
+  request_headers_json: string | Record<string, unknown>
+  request_body_json: string | Record<string, unknown>
+  response_status: number
+  response_json: string | Record<string, unknown>
+  error_message: string
+  sent_at: string | null
+  created_at: string
+  updated_at: string
+  task_no?: string
+  task_status?: string
+}
+
 export type TaskInventoryBindingRow = {
   id: number
   task_id: number
@@ -184,3 +211,8 @@ export type WebhookEventListQueryResult = {
   items: WebhookEventRow[]
   total: number
 }
+
+export type MessageDeliveryListQueryResult = {
+  items: MessageDeliveryRow[]
+  total: number
+}
diff --git a/docs/backend-typescript-migration-plan.md b/docs/backend-typescript-migration-plan.md
index 698cc87c..110c3081 100644
--- a/docs/backend-typescript-migration-plan.md
+++ b/docs/backend-typescript-migration-plan.md
@@ -219,12 +219,17 @@
    - `npm run build`
    - `npm test`
 11. `src/types/*.js` 已改写为真正的 `.ts` 类型导出文件，现有 JS JSDoc `import('...js').TypeName` 引用保持可用
+12. 低风险 repository 第二批已迁移到 `.ts`：
+    - `src/repositories/order-item-repo.ts`
+    - `src/repositories/message-delivery-repo.ts`
+    - `src/repositories/webhook-event-repo.ts`
+13. `MessageDeliveryRow` 与列表查询结果已进入共享 repository row 类型
 
 ## 下一步建议
 
 第一批继续推进时，建议按这个顺序：
 
-1. 继续迁移低风险 repository：`order-item-repo`、`message-delivery-repo`、`webhook-event-repo`
+1. 继续迁移剩余 repository：`admin-user-repo`、`inventory-repo`、`order-repo`、`task-repo`
 2. 拆分并迁移 `runtime.js`，把 env 解析、默认配置加载、配置合并分开
 3. 为 webhook、库存换码、自动发货补测试