diff --git a/package.json b/package.json
index 7a864c8..b6bc711 100644
--- a/package.json
+++ b/package.json
@@ -25,6 +25,7 @@
     "chalk": "^4.1.0",
     "chokidar": "^3.5.1",
     "esbuild": "^0.9.2",
+    "execa": "^5.0.0",
     "globby": "^11.0.2",
     "joycon": "^2.2.5",
     "postcss-load-config": "^3.0.1",
@@ -41,15 +42,15 @@
     "@types/node": "^14.14.35",
     "@types/resolve": "^1.20.0",
     "buble": "^0.20.0",
-    "execa": "^5.0.0",
     "fs-extra": "^9.1.0",
     "jest": "^26.6.3",
     "jju": "^1.4.0",
     "postcss": "^8.2.8",
     "postcss-simple-vars": "^6.0.3",
     "prettier": "^2.2.1",
-    "rollup-plugin-hashbang": "^2.2.2",
     "rollup-plugin-dts": "^2.0.1",
+    "rollup-plugin-hashbang": "^2.2.2",
+    "string-argv": "^0.3.1",
     "strip-json-comments": "^3.1.1",
     "svelte": "3.35.0",
     "ts-essentials": "^7.0.1",
diff --git a/src/cli.ts b/src/cli.ts
index 9b7db0a..d5bd293 100644
--- a/src/cli.ts
+++ b/src/cli.ts
@@ -40,6 +40,10 @@ async function main() {
     .option('--dts-resolve', 'Resolve externals types used for d.ts files')
     .option('--sourcemap', 'Generate sourcemap file')
     .option('--watch', 'Watch mode')
+    .option(
+      '--onSuccess <command>',
+      'Execute command after successful build, specially useful for watch mode'
+    )
     .option('--env.* <value>', 'Define compile-time env variables')
     .option('--define.* <value>', 'Define compile-time constants')
     .option('--external <name>', 'Mark specific packages as external')
diff --git a/src/index.ts b/src/index.ts
index 17f3ce3..edb7769 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -21,6 +21,9 @@ import { postcssPlugin } from './plugins/postcss'
 import { externalPlugin } from './plugins/external'
 import { sveltePlugin } from './plugins/svelte'
 import resolveFrom from 'resolve-from'
+import { parseArgsStringToArgv } from 'string-argv'
+import type { ChildProcess } from 'child_process'
+import execa from 'execa'
 
 const textDecoder = new TextDecoder('utf-8')
 
@@ -42,6 +45,7 @@ export type Options = {
   minifySyntax?: boolean
   keepNames?: boolean
   watch?: boolean
+  onSuccess?: string
   jsxFactory?: string
   jsxFragment?: string
   outDir?: string
@@ -344,6 +348,8 @@ export async function build(_options: Options) {
       })
   }
 
+  let existingOnSuccess: ChildProcess | undefined
+
   const buildAll = async () => {
     if (options.clean) {
       await removeFiles(['**/*', '!**/*.d.ts'], options.outDir)
@@ -356,6 +362,16 @@ export async function build(_options: Options) {
         runEsbuild(options, { format, css: index === 0 ? css : undefined })
       ),
     ])
+    if (options.onSuccess) {
+      if (existingOnSuccess) existingOnSuccess.kill()
+
+      const parts = parseArgsStringToArgv(options.onSuccess)
+      const exec = parts[0]
+      const args = parts.splice(1)
+      existingOnSuccess = execa(exec, args, {
+        stdio: 'inherit',
+      })
+    }
   }
 
   try {
diff --git a/test/index.test.ts b/test/index.test.ts
index 84008b5..bb6d3af 100644
--- a/test/index.test.ts
+++ b/test/index.test.ts
@@ -495,3 +495,18 @@ test('bundle svelte', async () => {
     "
   `)
 })
+
+test('onSuccess', async () => {
+  const randomNumber = Math.random() + ''
+  const { logs } = await run(
+    getTestName(),
+    {
+      'input.ts': "console.log('test');",
+    },
+    {
+      flags: ['--onSuccess', 'echo ' + randomNumber],
+    }
+  )
+
+  expect(logs.includes(randomNumber)).toBe(true)
+})
diff --git a/yarn.lock b/yarn.lock
index 8b5c0e5..ed45d0c 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -3801,6 +3801,11 @@ stealthy-require@^1.1.1:
   resolved "https://registry.yarnpkg.com/stealthy-require/-/stealthy-require-1.1.1.tgz#35b09875b4ff49f26a777e509b3090a3226bf24b"
   integrity sha1-NbCYdbT/SfJqd35QmzCQoyJr8ks=
 
+string-argv@^0.3.1:
+  version "0.3.1"
+  resolved "https://registry.yarnpkg.com/string-argv/-/string-argv-0.3.1.tgz#95e2fbec0427ae19184935f816d74aaa4c5c19da"
+  integrity sha512-a1uQGz7IyVy9YwhqjZIZu1c8JO8dNIe20xBmSS6qu9kv++k3JGzCVmprbNN5Kn+BgzD5E7YYwg1CcjuJMRNsvg==
+
 string-length@^4.0.1:
   version "4.0.1"
   resolved "https://registry.yarnpkg.com/string-length/-/string-length-4.0.1.tgz#4a973bf31ef77c4edbceadd6af2611996985f8a1"