diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
new file mode 100644
index 0000000..ef2cdd3
--- /dev/null
+++ b/.github/workflows/build.yml
@@ -0,0 +1,21 @@
+name: Build
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Check out
+        uses: actions/checkout@v3
+      - name: Setup Node
+        uses: actions/setup-node@v3
+        with:
+          node-version: 16
+      - name: Install
+        run: yarn
+      - name: Build
+        run: yarn build
diff --git a/package.json b/package.json
new file mode 100644
index 0000000..f0b4811
--- /dev/null
+++ b/package.json
@@ -0,0 +1,52 @@
+{
+  "name": "koishi-plugin-market-info",
+  "description": "Koishi plugin market information",
+  "version": "1.0.0",
+  "main": "lib/index.js",
+  "typings": "lib/index.d.ts",
+  "files": [
+    "lib",
+    "dist"
+  ],
+  "author": "Shigma <shigma10826@gmail.com>",
+  "license": "MIT",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/koishijs/koishi-plugin-market-info.git"
+  },
+  "bugs": {
+    "url": "https://github.com/koishijs/koishi-plugin-market-info/issues"
+  },
+  "homepage": "https://github.com/koishijs/koishi-plugin-market-info#readme",
+  "scripts": {
+    "build": "atsc -b"
+  },
+  "koishi": {
+    "browser": true,
+    "description": {
+      "en": "Plugin market information",
+      "zh": "插件市场信息查询与订阅"
+    }
+  },
+  "keywords": [
+    "chatbot",
+    "koishi",
+    "plugin",
+    "market",
+    "info",
+    "subscribe",
+    "update",
+    "registry",
+    "manager"
+  ],
+  "peerDependencies": {
+    "koishi": "^4.10.5"
+  },
+  "devDependencies": {
+    "@koishijs/registry": "^4.1.6",
+    "@types/node": "^17.0.45",
+    "atsc": "^1.2.1",
+    "koishi": "^4.10.5",
+    "typescript": "^4.9.3"
+  }
+}
diff --git a/src/index.ts b/src/index.ts
new file mode 100644
index 0000000..a2480f5
--- /dev/null
+++ b/src/index.ts
@@ -0,0 +1,76 @@
+import { Context, Dict, Logger, Schema, Time } from 'koishi'
+import type { MarketPackage, MarketResult } from '@koishijs/registry'
+
+const logger = new Logger('market')
+
+export const name = 'market-info'
+
+export interface Rule {
+  platform: string
+  channelId: string
+  selfId?: string
+  guildId?: string
+}
+
+export const Rule: Schema<Rule> = Schema.object({
+  platform: Schema.string().description('平台名称。').required(),
+  channelId: Schema.string().description('频道 ID。').required(),
+  guildId: Schema.string().description('群组 ID。'),
+  selfId: Schema.string().description('机器人 ID。'),
+})
+
+export interface Config {
+  rules: Rule[]
+  interval: number
+}
+
+export const Config: Schema<Config> = Schema.object({
+  rules: Schema.array(Rule).description('推送规则。'),
+  interval: Schema.number().default(Time.minute * 30).description('轮询间隔 (毫秒)。'),
+})
+
+function makeDict(result: MarketResult) {
+  const dict: Dict<MarketPackage> = {}
+  for (const object of result.objects) {
+    dict[object.name] = object
+  }
+  return dict
+}
+
+export function apply(ctx: Context, config: Config) {
+  const getMarket = async () => {
+    const data = await ctx.http.get<MarketResult>('https://registry.koishi.chat/market.json')
+    return makeDict(data)
+  }
+
+  ctx.on('ready', async () => {
+    let previous = await getMarket()
+
+    ctx.setInterval(async () => {
+      const current = await getMarket()
+      const diff = Object.keys({ ...previous, ...current }).map((name) => {
+        const version1 = previous[name]?.version
+        const version2 = current[name]?.version
+        if (version1 === version2) return
+        if (!version1) return '新增：' + name
+        if (!version2) return '移除：' + name
+        return `更新：${name} (${version1} → ${version2})`
+      }).filter(Boolean).sort()
+      previous = current
+      if (!diff.length) return
+
+      const content = ['[插件市场更新]', ...diff].join('\n')
+      logger.info(content)
+      for (let { channelId, platform, selfId, guildId } of config.rules) {
+        if (!selfId) {
+          const channel = await ctx.database.getChannel(platform, channelId, ['assignee', 'guildId'])
+          if (!channel || !channel.assignee) return
+          selfId = channel.assignee
+          guildId = channel.guildId
+        }
+        const bot = ctx.bots[`${platform}:${selfId}`]
+        bot?.sendMessage(channelId, content, guildId)
+      }
+    }, config.interval)
+  })
+}
diff --git a/tsconfig.json b/tsconfig.json
new file mode 100644
index 0000000..8d1fad2
--- /dev/null
+++ b/tsconfig.json
@@ -0,0 +1,17 @@
+{
+  "compilerOptions": {
+    "rootDir": "src",
+    "outDir": "lib",
+    "target": "es2020",
+    "module": "commonjs",
+    "declaration": true,
+    "composite": true,
+    "incremental": true,
+    "skipLibCheck": true,
+    "esModuleInterop": true,
+    "moduleResolution": "node"
+  },
+  "include": [
+    "src"
+  ]
+}
\ No newline at end of file