diff --git a/LICENSE-3rdparty.csv b/LICENSE-3rdparty.csv
index 09ceab21b9..68319d400b 100644
--- a/LICENSE-3rdparty.csv
+++ b/LICENSE-3rdparty.csv
@@ -56,7 +56,6 @@ dev,karma-webpack,MIT,Copyright JS Foundation and other contributors
 dev,lerna,MIT,Copyright 2015-present Lerna Contributors
 dev,minimatch,ISC,Copyright (c) Isaac Z. Schlueter and Contributors
 dev,node-forge,BSD,Copyright (c) 2010, Digital Bazaar, Inc.
-dev,npm-run-all,MIT,Copyright 2015 Toru Nagashima
 dev,pako,MIT,(C) 2014-2017 Vitaly Puzrin and Andrey Tupitsin
 dev,prettier,MIT,Copyright James Long and contributors
 dev,puppeteer,Apache-2.0,Copyright 2017 Google Inc.
diff --git a/package.json b/package.json
index f40fe00b83..3f7befb1d4 100644
--- a/package.json
+++ b/package.json
@@ -80,7 +80,6 @@
     "karma-webpack": "5.0.0",
     "lerna": "9.0.0",
     "minimatch": "10.0.3",
-    "npm-run-all": "4.1.5",
     "prettier": "3.6.2",
     "puppeteer": "24.26.0",
     "swc-loader": "0.2.6",
diff --git a/packages/core/package.json b/packages/core/package.json
index cefb22ed8e..a75630310a 100644
--- a/packages/core/package.json
+++ b/packages/core/package.json
@@ -8,10 +8,7 @@
   "sideEffects": false,
   "scripts": {
     "pack": "yarn pack",
-    "build": "run-p build:cjs build:esm",
-    "build:cjs": "rm -rf cjs && tsc -p tsconfig.cjs.json && yarn replace-build-env cjs",
-    "build:esm": "rm -rf esm && tsc -p tsconfig.esm.json && yarn replace-build-env esm",
-    "replace-build-env": "node ../../scripts/build/replace-build-env.ts"
+    "build": "node ../../scripts/build/build-package.ts --modules"
   },
   "repository": {
     "type": "git",
diff --git a/packages/core/tsconfig.cjs.json b/packages/core/tsconfig.cjs.json
deleted file mode 100644
index d78ac200b2..0000000000
--- a/packages/core/tsconfig.cjs.json
+++ /dev/null
@@ -1,12 +0,0 @@
-{
-  "extends": "../../tsconfig.base.json",
-  "compilerOptions": {
-    "baseUrl": ".",
-    "declaration": true,
-    "module": "commonjs",
-    "rootDir": "./src/",
-    "outDir": "./cjs/"
-  },
-  "include": ["./src/**/*.ts"],
-  "exclude": ["./src/**/*.spec.ts", "./src/**/*.specHelper.ts"]
-}
diff --git a/packages/core/tsconfig.esm.json b/packages/core/tsconfig.esm.json
deleted file mode 100644
index 9d1d447af3..0000000000
--- a/packages/core/tsconfig.esm.json
+++ /dev/null
@@ -1,11 +0,0 @@
-{
-  "extends": "../../tsconfig.base.json",
-  "compilerOptions": {
-    "baseUrl": ".",
-    "declaration": true,
-    "rootDir": "./src/",
-    "outDir": "./esm/"
-  },
-  "include": ["./src/**/*.ts"],
-  "exclude": ["./src/**/*.spec.ts", "./src/**/*.specHelper.ts"]
-}
diff --git a/packages/flagging/package.json b/packages/flagging/package.json
index bc188a9716..523f64e9fe 100644
--- a/packages/flagging/package.json
+++ b/packages/flagging/package.json
@@ -7,11 +7,8 @@
   "types": "cjs/entries/main.d.ts",
   "scripts": {
     "pack": "yarn pack",
-    "build": "run-p build:cjs build:esm build:bundle",
-    "build:bundle": "rm -rf bundle && SDK_SETUP=cdn webpack --disable-interpret --mode=production",
-    "build:cjs": "rm -rf cjs && tsc -p tsconfig.cjs.json && yarn replace-build-env cjs",
-    "build:esm": "rm -rf esm && tsc -p tsconfig.esm.json && yarn replace-build-env esm",
-    "replace-build-env": "node ../../scripts/build/replace-build-env.ts"
+    "build": "node ../../scripts/build/build-package.ts --modules --bundle datadog-flagging.js",
+    "build:bundle": "node ../../scripts/build/build-package.ts --bundle datadog-flagging.js"
   },
   "dependencies": {
     "@datadog/browser-core": "6.22.0"
@@ -36,7 +33,6 @@
     "access": "public"
   },
   "devDependencies": {
-    "npm-run-all": "4.1.5",
     "webpack": "5.102.1"
   }
 }
diff --git a/packages/flagging/tsconfig.cjs.json b/packages/flagging/tsconfig.cjs.json
deleted file mode 100644
index d78ac200b2..0000000000
--- a/packages/flagging/tsconfig.cjs.json
+++ /dev/null
@@ -1,12 +0,0 @@
-{
-  "extends": "../../tsconfig.base.json",
-  "compilerOptions": {
-    "baseUrl": ".",
-    "declaration": true,
-    "module": "commonjs",
-    "rootDir": "./src/",
-    "outDir": "./cjs/"
-  },
-  "include": ["./src/**/*.ts"],
-  "exclude": ["./src/**/*.spec.ts", "./src/**/*.specHelper.ts"]
-}
diff --git a/packages/flagging/tsconfig.esm.json b/packages/flagging/tsconfig.esm.json
deleted file mode 100644
index fee4f61227..0000000000
--- a/packages/flagging/tsconfig.esm.json
+++ /dev/null
@@ -1,12 +0,0 @@
-{
-  "extends": "../../tsconfig.base.json",
-  "compilerOptions": {
-    "baseUrl": ".",
-    "declaration": true,
-    "module": "es6",
-    "rootDir": "./src/",
-    "outDir": "./esm/"
-  },
-  "include": ["./src/**/*.ts"],
-  "exclude": ["./src/**/*.spec.ts", "./src/**/*.specHelper.ts"]
-}
diff --git a/packages/flagging/webpack.config.mts b/packages/flagging/webpack.config.mts
deleted file mode 100644
index f12387f8d3..0000000000
--- a/packages/flagging/webpack.config.mts
+++ /dev/null
@@ -1,10 +0,0 @@
-import path from 'path'
-import type webpack from 'webpack'
-import webpackBase from '../../webpack.base.ts'
-
-export default (_env: unknown, argv: { mode?: webpack.Configuration['mode'] }) =>
-  webpackBase({
-    mode: argv.mode,
-    entry: path.resolve(import.meta.dirname, 'src/entries/main.ts'),
-    filename: 'datadog-flagging.js',
-  })
diff --git a/packages/logs/package.json b/packages/logs/package.json
index a3a96902d2..3d00c9cd30 100644
--- a/packages/logs/package.json
+++ b/packages/logs/package.json
@@ -7,11 +7,8 @@
   "types": "cjs/entries/main.d.ts",
   "scripts": {
     "pack": "yarn pack",
-    "build": "run-p build:cjs build:esm build:bundle",
-    "build:bundle": "rm -rf bundle && SDK_SETUP=cdn webpack --disable-interpret  --mode=production",
-    "build:cjs": "rm -rf cjs && tsc -p tsconfig.cjs.json && yarn replace-build-env cjs",
-    "build:esm": "rm -rf esm && tsc -p tsconfig.esm.json && yarn replace-build-env esm",
-    "replace-build-env": "node ../../scripts/build/replace-build-env.ts"
+    "build": "node ../../scripts/build/build-package.ts --modules --bundle datadog-logs.js",
+    "build:bundle": "node ../../scripts/build/build-package.ts --bundle datadog-logs.js"
   },
   "dependencies": {
     "@datadog/browser-core": "6.23.0"
diff --git a/packages/logs/tsconfig.cjs.json b/packages/logs/tsconfig.cjs.json
deleted file mode 100644
index d78ac200b2..0000000000
--- a/packages/logs/tsconfig.cjs.json
+++ /dev/null
@@ -1,12 +0,0 @@
-{
-  "extends": "../../tsconfig.base.json",
-  "compilerOptions": {
-    "baseUrl": ".",
-    "declaration": true,
-    "module": "commonjs",
-    "rootDir": "./src/",
-    "outDir": "./cjs/"
-  },
-  "include": ["./src/**/*.ts"],
-  "exclude": ["./src/**/*.spec.ts", "./src/**/*.specHelper.ts"]
-}
diff --git a/packages/logs/tsconfig.esm.json b/packages/logs/tsconfig.esm.json
deleted file mode 100644
index fee4f61227..0000000000
--- a/packages/logs/tsconfig.esm.json
+++ /dev/null
@@ -1,12 +0,0 @@
-{
-  "extends": "../../tsconfig.base.json",
-  "compilerOptions": {
-    "baseUrl": ".",
-    "declaration": true,
-    "module": "es6",
-    "rootDir": "./src/",
-    "outDir": "./esm/"
-  },
-  "include": ["./src/**/*.ts"],
-  "exclude": ["./src/**/*.spec.ts", "./src/**/*.specHelper.ts"]
-}
diff --git a/packages/logs/webpack.config.mts b/packages/logs/webpack.config.mts
deleted file mode 100644
index 0ab813e642..0000000000
--- a/packages/logs/webpack.config.mts
+++ /dev/null
@@ -1,10 +0,0 @@
-import path from 'path'
-import type webpack from 'webpack'
-import webpackBase from '../../webpack.base.ts'
-
-export default (_env: unknown, argv: { mode?: webpack.Configuration['mode'] }) =>
-  webpackBase({
-    mode: argv.mode,
-    entry: path.resolve(import.meta.dirname, 'src/entries/main.ts'),
-    filename: 'datadog-logs.js',
-  })
diff --git a/packages/rum-core/package.json b/packages/rum-core/package.json
index f0dd7783da..f541f747c1 100644
--- a/packages/rum-core/package.json
+++ b/packages/rum-core/package.json
@@ -7,10 +7,7 @@
   "types": "cjs/index.d.ts",
   "scripts": {
     "pack": "yarn pack",
-    "build": "run-p build:cjs build:esm",
-    "build:cjs": "rm -rf cjs && tsc -p tsconfig.cjs.json && yarn replace-build-env cjs",
-    "build:esm": "rm -rf esm && tsc -p tsconfig.esm.json && yarn replace-build-env esm",
-    "replace-build-env": "node ../../scripts/build/replace-build-env.ts"
+    "build": "node ../../scripts/build/build-package.ts --modules"
   },
   "dependencies": {
     "@datadog/browser-core": "6.23.0"
diff --git a/packages/rum-core/tsconfig.cjs.json b/packages/rum-core/tsconfig.cjs.json
deleted file mode 100644
index d78ac200b2..0000000000
--- a/packages/rum-core/tsconfig.cjs.json
+++ /dev/null
@@ -1,12 +0,0 @@
-{
-  "extends": "../../tsconfig.base.json",
-  "compilerOptions": {
-    "baseUrl": ".",
-    "declaration": true,
-    "module": "commonjs",
-    "rootDir": "./src/",
-    "outDir": "./cjs/"
-  },
-  "include": ["./src/**/*.ts"],
-  "exclude": ["./src/**/*.spec.ts", "./src/**/*.specHelper.ts"]
-}
diff --git a/packages/rum-core/tsconfig.esm.json b/packages/rum-core/tsconfig.esm.json
deleted file mode 100644
index 9d1d447af3..0000000000
--- a/packages/rum-core/tsconfig.esm.json
+++ /dev/null
@@ -1,11 +0,0 @@
-{
-  "extends": "../../tsconfig.base.json",
-  "compilerOptions": {
-    "baseUrl": ".",
-    "declaration": true,
-    "rootDir": "./src/",
-    "outDir": "./esm/"
-  },
-  "include": ["./src/**/*.ts"],
-  "exclude": ["./src/**/*.spec.ts", "./src/**/*.specHelper.ts"]
-}
diff --git a/packages/rum-react/package.json b/packages/rum-react/package.json
index ac24842189..0171cdd876 100644
--- a/packages/rum-react/package.json
+++ b/packages/rum-react/package.json
@@ -7,9 +7,7 @@
   "types": "cjs/entries/main.d.ts",
   "scripts": {
     "pack": "yarn pack",
-    "build": "run-p build:cjs build:esm",
-    "build:cjs": "rm -rf cjs && tsc -p tsconfig.cjs.json --noCheck",
-    "build:esm": "rm -rf esm && tsc -p tsconfig.esm.json --noCheck",
+    "build": "node ../../scripts/build/build-package.ts --modules",
     "prepack": "npm run build"
   },
   "dependencies": {
diff --git a/packages/rum-react/tsconfig.cjs.json b/packages/rum-react/tsconfig.cjs.json
deleted file mode 100644
index d78ac200b2..0000000000
--- a/packages/rum-react/tsconfig.cjs.json
+++ /dev/null
@@ -1,12 +0,0 @@
-{
-  "extends": "../../tsconfig.base.json",
-  "compilerOptions": {
-    "baseUrl": ".",
-    "declaration": true,
-    "module": "commonjs",
-    "rootDir": "./src/",
-    "outDir": "./cjs/"
-  },
-  "include": ["./src/**/*.ts"],
-  "exclude": ["./src/**/*.spec.ts", "./src/**/*.specHelper.ts"]
-}
diff --git a/packages/rum-react/tsconfig.esm.json b/packages/rum-react/tsconfig.esm.json
deleted file mode 100644
index 9d1d447af3..0000000000
--- a/packages/rum-react/tsconfig.esm.json
+++ /dev/null
@@ -1,11 +0,0 @@
-{
-  "extends": "../../tsconfig.base.json",
-  "compilerOptions": {
-    "baseUrl": ".",
-    "declaration": true,
-    "rootDir": "./src/",
-    "outDir": "./esm/"
-  },
-  "include": ["./src/**/*.ts"],
-  "exclude": ["./src/**/*.spec.ts", "./src/**/*.specHelper.ts"]
-}
diff --git a/packages/rum-slim/package.json b/packages/rum-slim/package.json
index 8f67cb2401..a974852aba 100644
--- a/packages/rum-slim/package.json
+++ b/packages/rum-slim/package.json
@@ -7,10 +7,8 @@
   "types": "cjs/entries/main.d.ts",
   "scripts": {
     "pack": "yarn pack",
-    "build": "run-p build:cjs build:esm build:bundle",
-    "build:bundle": "rm -rf bundle && SDK_SETUP=cdn webpack --disable-interpret --mode=production",
-    "build:cjs": "rm -rf cjs && tsc -p tsconfig.cjs.json",
-    "build:esm": "rm -rf esm && tsc -p tsconfig.esm.json"
+    "build": "node ../../scripts/build/build-package.ts --modules --bundle datadog-rum-slim.js",
+    "build:bundle": "node ../../scripts/build/build-package.ts --bundle datadog-rum-slim.js"
   },
   "dependencies": {
     "@datadog/browser-core": "6.23.0",
diff --git a/packages/rum-slim/tsconfig.cjs.json b/packages/rum-slim/tsconfig.cjs.json
deleted file mode 100644
index d78ac200b2..0000000000
--- a/packages/rum-slim/tsconfig.cjs.json
+++ /dev/null
@@ -1,12 +0,0 @@
-{
-  "extends": "../../tsconfig.base.json",
-  "compilerOptions": {
-    "baseUrl": ".",
-    "declaration": true,
-    "module": "commonjs",
-    "rootDir": "./src/",
-    "outDir": "./cjs/"
-  },
-  "include": ["./src/**/*.ts"],
-  "exclude": ["./src/**/*.spec.ts", "./src/**/*.specHelper.ts"]
-}
diff --git a/packages/rum-slim/tsconfig.esm.json b/packages/rum-slim/tsconfig.esm.json
deleted file mode 100644
index 9d1d447af3..0000000000
--- a/packages/rum-slim/tsconfig.esm.json
+++ /dev/null
@@ -1,11 +0,0 @@
-{
-  "extends": "../../tsconfig.base.json",
-  "compilerOptions": {
-    "baseUrl": ".",
-    "declaration": true,
-    "rootDir": "./src/",
-    "outDir": "./esm/"
-  },
-  "include": ["./src/**/*.ts"],
-  "exclude": ["./src/**/*.spec.ts", "./src/**/*.specHelper.ts"]
-}
diff --git a/packages/rum-slim/webpack.config.mts b/packages/rum-slim/webpack.config.mts
deleted file mode 100644
index 26cb6f3743..0000000000
--- a/packages/rum-slim/webpack.config.mts
+++ /dev/null
@@ -1,10 +0,0 @@
-import path from 'path'
-import type webpack from 'webpack'
-import webpackBase from '../../webpack.base.ts'
-
-export default (_env: unknown, argv: { mode?: webpack.Configuration['mode'] }) =>
-  webpackBase({
-    mode: argv.mode,
-    entry: path.resolve(import.meta.dirname, 'src/entries/main.ts'),
-    filename: 'datadog-rum-slim.js',
-  })
diff --git a/packages/rum/package.json b/packages/rum/package.json
index 8c3ad07013..46e16fdd53 100644
--- a/packages/rum/package.json
+++ b/packages/rum/package.json
@@ -7,11 +7,8 @@
   "types": "cjs/entries/main.d.ts",
   "scripts": {
     "pack": "yarn pack",
-    "build": "run-p build:cjs build:esm build:bundle",
-    "build:bundle": "rm -rf bundle && SDK_SETUP=cdn webpack --disable-interpret --mode=production",
-    "build:cjs": "rm -rf cjs && tsc -p tsconfig.cjs.json && yarn replace-build-env cjs",
-    "build:esm": "rm -rf esm && tsc -p tsconfig.esm.json && yarn replace-build-env esm",
-    "replace-build-env": "node ../../scripts/build/replace-build-env.ts"
+    "build": "node ../../scripts/build/build-package.ts --modules --bundle datadog-rum.js",
+    "build:bundle": "node ../../scripts/build/build-package.ts --bundle datadog-rum.js"
   },
   "dependencies": {
     "@datadog/browser-core": "6.23.0",
diff --git a/packages/rum/tsconfig.cjs.json b/packages/rum/tsconfig.cjs.json
deleted file mode 100644
index 1106af4343..0000000000
--- a/packages/rum/tsconfig.cjs.json
+++ /dev/null
@@ -1,13 +0,0 @@
-{
-  "extends": "../../tsconfig.base.json",
-  "compilerOptions": {
-    "baseUrl": ".",
-    "declaration": true,
-    "allowJs": true,
-    "module": "commonjs",
-    "rootDir": "./src/",
-    "outDir": "./cjs/"
-  },
-  "include": ["./src"],
-  "exclude": ["./src/**/*.spec.ts", "./src/**/*.specHelper.ts"]
-}
diff --git a/packages/rum/tsconfig.esm.json b/packages/rum/tsconfig.esm.json
deleted file mode 100644
index 815687627a..0000000000
--- a/packages/rum/tsconfig.esm.json
+++ /dev/null
@@ -1,12 +0,0 @@
-{
-  "extends": "../../tsconfig.base.json",
-  "compilerOptions": {
-    "baseUrl": ".",
-    "declaration": true,
-    "allowJs": true,
-    "rootDir": "./src/",
-    "outDir": "./esm/"
-  },
-  "include": ["./src"],
-  "exclude": ["./src/**/*.spec.ts", "./src/**/*.specHelper.ts"]
-}
diff --git a/packages/rum/webpack.config.mts b/packages/rum/webpack.config.mts
deleted file mode 100644
index 74361fe83d..0000000000
--- a/packages/rum/webpack.config.mts
+++ /dev/null
@@ -1,10 +0,0 @@
-import path from 'path'
-import type webpack from 'webpack'
-import webpackBase from '../../webpack.base.ts'
-
-export default (_env: unknown, argv: { mode?: webpack.Configuration['mode'] }) =>
-  webpackBase({
-    mode: argv.mode,
-    entry: path.resolve(import.meta.dirname, 'src/entries/main.ts'),
-    filename: 'datadog-rum.js',
-  })
diff --git a/packages/worker/package.json b/packages/worker/package.json
index b6e1cdb9c2..eb2e6ad622 100644
--- a/packages/worker/package.json
+++ b/packages/worker/package.json
@@ -5,7 +5,8 @@
   "main": "bundle/worker.js",
   "scripts": {
     "pack": "yarn pack",
-    "build": "rm -rf bundle && webpack --disable-interpret --mode=production"
+    "build": "node ../../scripts/build/build-package.ts --bundle worker.js",
+    "build:bundle": "yarn build"
   },
   "dependencies": {
     "@datadog/browser-core": "6.23.0"
diff --git a/packages/worker/webpack.config.mts b/packages/worker/webpack.config.mts
deleted file mode 100644
index 7f75d48873..0000000000
--- a/packages/worker/webpack.config.mts
+++ /dev/null
@@ -1,10 +0,0 @@
-import path from 'path'
-import type webpack from 'webpack'
-import webpackBase from '../../webpack.base.ts'
-
-export default (_env: unknown, argv: { mode?: webpack.Configuration['mode'] }) =>
-  webpackBase({
-    mode: argv.mode,
-    entry: path.resolve(import.meta.dirname, 'src/entries/main.ts'),
-    filename: 'worker.js',
-  })
diff --git a/scripts/build/build-package.ts b/scripts/build/build-package.ts
new file mode 100644
index 0000000000..35de4985c5
--- /dev/null
+++ b/scripts/build/build-package.ts
@@ -0,0 +1,156 @@
+import fs from 'node:fs/promises'
+import { parseArgs } from 'node:util'
+import path from 'node:path'
+import { globSync } from 'node:fs'
+import ts from 'typescript'
+import webpack from 'webpack'
+import webpackBase from '../../webpack.base.ts'
+
+import { printLog, runMain } from '../lib/executionUtils.ts'
+import { modifyFile } from '../lib/filesUtils.ts'
+import { buildEnvKeys, getBuildEnvValue } from '../lib/buildEnv.ts'
+
+runMain(async () => {
+  const { values } = parseArgs({
+    options: {
+      modules: {
+        type: 'boolean',
+      },
+      bundle: {
+        type: 'string',
+      },
+      verbose: {
+        type: 'boolean',
+        default: false,
+      },
+    },
+  })
+
+  if (values.modules) {
+    printLog('Building modules...')
+    await buildModules({
+      outDir: './cjs',
+      module: 'commonjs',
+      verbose: values.verbose,
+    })
+    await buildModules({
+      outDir: './esm',
+      module: 'es2020',
+      verbose: values.verbose,
+    })
+  }
+
+  if (values.bundle) {
+    printLog('Building bundle...')
+    await buildBundle({
+      filename: values.bundle,
+      verbose: values.verbose,
+    })
+  }
+
+  printLog('Done.')
+})
+
+async function buildBundle({ filename, verbose }: { filename: string; verbose: boolean }) {
+  await fs.rm('./bundle', { recursive: true, force: true })
+  return new Promise<void>((resolve, reject) => {
+    webpack(
+      webpackBase({
+        mode: 'production',
+        entry: './src/entries/main.ts',
+        filename,
+      }),
+      (error, stats) => {
+        if (error) {
+          reject(error)
+          return
+        }
+
+        if (verbose) {
+          console.log(stats!.toString({ colors: true }))
+        }
+        resolve()
+      }
+    )
+  })
+}
+
+async function buildModules({ outDir, module, verbose }: { outDir: string; module: string; verbose: boolean }) {
+  await fs.rm(outDir, { recursive: true, force: true })
+
+  // TODO: in the future, consider building packages with something else than typescript (ex:
+  // rspack, tsdown...)
+
+  const diagnostics = buildWithTypeScript({
+    extends: '../../tsconfig.base.json',
+    compilerOptions: {
+      baseUrl: '.',
+      declaration: true,
+      allowJs: true,
+      module,
+      rootDir: './src/',
+      outDir,
+    },
+    include: ['./src'],
+    exclude: ['./src/**/*.spec.*', './src/**/*.specHelper.*'],
+  })
+
+  if (diagnostics.length) {
+    printTypeScriptDiagnostics(diagnostics)
+    throw new Error('Failed to build package due to TypeScript errors')
+  }
+
+  await replaceBuildEnvInDirectory(outDir, { verbose })
+}
+
+async function replaceBuildEnvInDirectory(dir: string, { verbose }: { verbose: boolean }) {
+  for (const relativePath of globSync('**/*.js', { cwd: dir })) {
+    const absolutePath = path.resolve(dir, relativePath)
+    if (await modifyFile(absolutePath, (content: string) => replaceBuildEnv(content))) {
+      if (verbose) {
+        printLog(`Replaced BuildEnv in ${absolutePath}`)
+      }
+    }
+  }
+
+  function replaceBuildEnv(content: string): string {
+    return buildEnvKeys.reduce(
+      (content, key) => content.replaceAll(`__BUILD_ENV__${key}__`, () => JSON.stringify(getBuildEnvValue(key))),
+      content
+    )
+  }
+}
+
+function buildWithTypeScript(configuration: { [key: string]: unknown }) {
+  const parsedConfiguration = ts.parseJsonConfigFileContent(
+    configuration,
+    ts.sys,
+    process.cwd(),
+    undefined,
+    'tsconfig.json' // just used in messages
+  )
+
+  const host = ts.createCompilerHost(parsedConfiguration.options)
+  const program = ts.createProgram({
+    rootNames: parsedConfiguration.fileNames,
+    options: parsedConfiguration.options,
+    host,
+  })
+
+  const emitResult = program.emit()
+  if (emitResult.emitSkipped) {
+    throw new Error('No files were emitted')
+  }
+
+  return [...ts.getPreEmitDiagnostics(program), ...emitResult.diagnostics]
+}
+
+function printTypeScriptDiagnostics(diagnostics: ts.Diagnostic[]) {
+  const formatHost: ts.FormatDiagnosticsHost = {
+    getCanonicalFileName: (f) => f,
+    // eslint-disable-next-line @typescript-eslint/unbound-method
+    getCurrentDirectory: ts.sys.getCurrentDirectory,
+    getNewLine: () => ts.sys.newLine,
+  }
+  console.error(ts.formatDiagnosticsWithColorAndContext(diagnostics, formatHost))
+}
diff --git a/scripts/build/replace-build-env.ts b/scripts/build/replace-build-env.ts
deleted file mode 100644
index 781070e4db..0000000000
--- a/scripts/build/replace-build-env.ts
+++ /dev/null
@@ -1,28 +0,0 @@
-import { globSync } from 'node:fs'
-import { resolve } from 'node:path'
-import { printLog, runMain } from '../lib/executionUtils.ts'
-import { modifyFile } from '../lib/filesUtils.ts'
-import { buildEnvKeys, getBuildEnvValue } from '../lib/buildEnv.ts'
-
-/**
- * Replace BuildEnv in build files
- * Usage:
- * BUILD_MODE=zzz node replace-build-env.ts /path/to/build/directory
- */
-
-runMain(async () => {
-  const buildDirectory = process.argv[2]
-
-  for (const path of globSync('**/*.js', { cwd: buildDirectory })) {
-    if (await modifyFile(resolve(buildDirectory, path), (content: string) => replaceBuildEnv(content))) {
-      printLog(`Replaced BuildEnv in ${path}`)
-    }
-  }
-})
-
-function replaceBuildEnv(content: string): string {
-  return buildEnvKeys.reduce(
-    (content, key) => content.replaceAll(`__BUILD_ENV__${key}__`, () => JSON.stringify(getBuildEnvValue(key))),
-    content
-  )
-}
diff --git a/scripts/check-packages.ts b/scripts/check-packages.ts
index 09e69491d5..69a1c11568 100644
--- a/scripts/check-packages.ts
+++ b/scripts/check-packages.ts
@@ -48,7 +48,7 @@ function getPackageFiles(packagePath: string): string[] {
   //
   // [1]: Quoting Lerna doc: "Lerna always uses npm to publish packages."
   // https://lerna.js.org/docs/features/version-and-publish#from-package
-  const output = command`npm pack --dry-run --json`.withCurrentWorkingDirectory(packagePath).run()
+  const output = command`npm pack --ignore-scripts --dry-run --json`.withCurrentWorkingDirectory(packagePath).run()
   const parsed: NpmPackOutput[] = JSON.parse(output)
   return parsed[0].files.map((file) => file.path)
 }
diff --git a/scripts/dev-server.ts b/scripts/dev-server.ts
index f08be09627..64e8706fb9 100644
--- a/scripts/dev-server.ts
+++ b/scripts/dev-server.ts
@@ -4,16 +4,13 @@ import HtmlWebpackPlugin from 'html-webpack-plugin'
 import webpack from 'webpack'
 import cors from 'cors'
 import webpackBase from '../webpack.base.ts'
-import logsConfig from '../packages/logs/webpack.config.mts'
-import rumSlimConfig from '../packages/rum-slim/webpack.config.mts'
-import rumConfig from '../packages/rum/webpack.config.mts'
-import flaggingConfig from '../packages/flagging/webpack.config.mts'
-import workerConfig from '../packages/worker/webpack.config.mts'
 import { printLog, runMain } from './lib/executionUtils.ts'
 
 const sandboxPath = './sandbox'
 const port = 8080
 
+const PACKAGES_WITH_BUNDLE = ['rum', 'rum-slim', 'logs', 'flagging', 'worker']
+
 runMain(() => {
   const app = express()
   app.use(createStaticSandboxApp())
@@ -25,8 +22,19 @@ function createStaticSandboxApp(): express.Application {
   const app = express()
   app.use(cors())
   app.use(express.static(sandboxPath))
-  for (const config of [rumConfig, rumSlimConfig, logsConfig, flaggingConfig, workerConfig]) {
-    app.use(middleware(webpack(config(null, { mode: 'development' }))!))
+  for (const packageName of PACKAGES_WITH_BUNDLE) {
+    const packagePath = `./packages/${packageName}`
+    app.use(
+      middleware(
+        webpack(
+          webpackBase({
+            mode: 'development',
+            entry: `${packagePath}/src/entries/main.ts`,
+            filename: packageName === 'worker' ? 'worker.js' : `datadog-${packageName}.js`,
+          })
+        )!
+      )
+    )
   }
 
   // Redirect suffixed files
diff --git a/yarn.lock b/yarn.lock
index 9e7fc29780..196759c986 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -236,7 +236,6 @@ __metadata:
   resolution: "@datadog/browser-flagging@workspace:packages/flagging"
   dependencies:
     "@datadog/browser-core": "npm:6.22.0"
-    npm-run-all: "npm:4.1.5"
     webpack: "npm:5.102.1"
   peerDependencies:
     "@datadog/browser-rum": 6.22.0
@@ -3339,15 +3338,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"ansi-styles@npm:^3.2.1":
-  version: 3.2.1
-  resolution: "ansi-styles@npm:3.2.1"
-  dependencies:
-    color-convert: "npm:^1.9.0"
-  checksum: 10c0/ece5a8ef069fcc5298f67e3f4771a663129abd174ea2dfa87923a2be2abf6cd367ef72ac87942da00ce85bd1d651d4cd8595aebdb1b385889b89b205860e977b
-  languageName: node
-  linkType: hard
-
 "ansi-styles@npm:^4.0.0, ansi-styles@npm:^4.1.0":
   version: 4.3.0
   resolution: "ansi-styles@npm:4.3.0"
@@ -3911,7 +3901,6 @@ __metadata:
     karma-webpack: "npm:5.0.0"
     lerna: "npm:9.0.0"
     minimatch: "npm:10.0.3"
-    npm-run-all: "npm:4.1.5"
     prettier: "npm:3.6.2"
     puppeteer: "npm:24.26.0"
     swc-loader: "npm:0.2.6"
@@ -4165,17 +4154,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"chalk@npm:^2.4.1":
-  version: 2.4.2
-  resolution: "chalk@npm:2.4.2"
-  dependencies:
-    ansi-styles: "npm:^3.2.1"
-    escape-string-regexp: "npm:^1.0.5"
-    supports-color: "npm:^5.3.0"
-  checksum: 10c0/e6543f02ec877732e3a2d1c3c3323ddb4d39fbab687c23f526e25bd4c6a9bf3b83a696e8c769d078e04e5754921648f7821b2a2acfd16c550435fd630026e073
-  languageName: node
-  linkType: hard
-
 "chalk@npm:^4.0.0, chalk@npm:^4.1.0, chalk@npm:^4.1.2":
   version: 4.1.2
   resolution: "chalk@npm:4.1.2"
@@ -4405,15 +4383,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"color-convert@npm:^1.9.0":
-  version: 1.9.3
-  resolution: "color-convert@npm:1.9.3"
-  dependencies:
-    color-name: "npm:1.1.3"
-  checksum: 10c0/5ad3c534949a8c68fca8fbc6f09068f435f0ad290ab8b2f76841b9e6af7e0bb57b98cb05b0e19fe33f5d91e5a8611ad457e5f69e0a484caad1f7487fd0e8253c
-  languageName: node
-  linkType: hard
-
 "color-convert@npm:^2.0.1":
   version: 2.0.1
   resolution: "color-convert@npm:2.0.1"
@@ -4423,13 +4392,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"color-name@npm:1.1.3":
-  version: 1.1.3
-  resolution: "color-name@npm:1.1.3"
-  checksum: 10c0/566a3d42cca25b9b3cd5528cd7754b8e89c0eb646b7f214e8e2eaddb69994ac5f0557d9c175eb5d8f0ad73531140d9c47525085ee752a91a2ab15ab459caf6d6
-  languageName: node
-  linkType: hard
-
 "color-name@npm:~1.1.4":
   version: 1.1.4
   resolution: "color-name@npm:1.1.4"
@@ -4848,19 +4810,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"cross-spawn@npm:^6.0.5":
-  version: 6.0.6
-  resolution: "cross-spawn@npm:6.0.6"
-  dependencies:
-    nice-try: "npm:^1.0.4"
-    path-key: "npm:^2.0.1"
-    semver: "npm:^5.5.0"
-    shebang-command: "npm:^1.2.0"
-    which: "npm:^1.2.9"
-  checksum: 10c0/bf61fb890e8635102ea9bce050515cf915ff6a50ccaa0b37a17dc82fded0fb3ed7af5478b9367b86baee19127ad86af4be51d209f64fd6638c0862dca185fe1d
-  languageName: node
-  linkType: hard
-
 "cross-spawn@npm:^7.0.3, cross-spawn@npm:^7.0.6":
   version: 7.0.6
   resolution: "cross-spawn@npm:7.0.6"
@@ -7098,13 +7047,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"has-flag@npm:^3.0.0":
-  version: 3.0.0
-  resolution: "has-flag@npm:3.0.0"
-  checksum: 10c0/1c6c83b14b8b1b3c25b0727b8ba3e3b647f99e9e6e13eb7322107261de07a4c1be56fc0d45678fc376e09772a3a1642ccdaf8fc69bdf123b6c086598397ce473
-  languageName: node
-  linkType: hard
-
 "has-flag@npm:^4.0.0":
   version: 4.0.0
   resolution: "has-flag@npm:4.0.0"
@@ -9132,13 +9074,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"memorystream@npm:^0.3.1":
-  version: 0.3.1
-  resolution: "memorystream@npm:0.3.1"
-  checksum: 10c0/4bd164657711d9747ff5edb0508b2944414da3464b7fe21ac5c67cf35bba975c4b446a0124bd0f9a8be54cfc18faf92e92bd77563a20328b1ccf2ff04e9f39b9
-  languageName: node
-  linkType: hard
-
 "meow@npm:^8.1.2":
   version: 8.1.2
   resolution: "meow@npm:8.1.2"
@@ -9631,13 +9566,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"nice-try@npm:^1.0.4":
-  version: 1.0.5
-  resolution: "nice-try@npm:1.0.5"
-  checksum: 10c0/95568c1b73e1d0d4069a3e3061a2102d854513d37bcfda73300015b7ba4868d3b27c198d1dbbd8ebdef4112fc2ed9e895d4a0f2e1cce0bd334f2a1346dc9205f
-  languageName: node
-  linkType: hard
-
 "no-case@npm:^3.0.4":
   version: 3.0.4
   resolution: "no-case@npm:3.0.4"
@@ -9899,27 +9827,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"npm-run-all@npm:4.1.5":
-  version: 4.1.5
-  resolution: "npm-run-all@npm:4.1.5"
-  dependencies:
-    ansi-styles: "npm:^3.2.1"
-    chalk: "npm:^2.4.1"
-    cross-spawn: "npm:^6.0.5"
-    memorystream: "npm:^0.3.1"
-    minimatch: "npm:^3.0.4"
-    pidtree: "npm:^0.3.0"
-    read-pkg: "npm:^3.0.0"
-    shell-quote: "npm:^1.6.1"
-    string.prototype.padend: "npm:^3.0.0"
-  bin:
-    npm-run-all: bin/npm-run-all/index.js
-    run-p: bin/run-p/index.js
-    run-s: bin/run-s/index.js
-  checksum: 10c0/736ee39bd35454d3efaa4a2e53eba6c523e2e17fba21a18edcce6b221f5cab62000bef16bb6ae8aff9e615831e6b0eb25ab51d52d60e6fa6f4ea880e4c6d31f4
-  languageName: node
-  linkType: hard
-
 "npm-run-path@npm:^4.0.1":
   version: 4.0.1
   resolution: "npm-run-path@npm:4.0.1"
@@ -10592,13 +10499,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"path-key@npm:^2.0.1":
-  version: 2.0.1
-  resolution: "path-key@npm:2.0.1"
-  checksum: 10c0/dd2044f029a8e58ac31d2bf34c34b93c3095c1481942960e84dd2faa95bbb71b9b762a106aead0646695330936414b31ca0bd862bf488a937ad17c8c5d73b32b
-  languageName: node
-  linkType: hard
-
 "path-key@npm:^3.0.0, path-key@npm:^3.1.0":
   version: 3.1.1
   resolution: "path-key@npm:3.1.1"
@@ -10705,15 +10605,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"pidtree@npm:^0.3.0":
-  version: 0.3.1
-  resolution: "pidtree@npm:0.3.1"
-  bin:
-    pidtree: bin/pidtree.js
-  checksum: 10c0/cd69b0182f749f45ab48584e3442c48c5dc4512502c18d5b0147a33b042c41a4db4269b9ce2f7c48f11833ee5e79d81f5ebc6f7bf8372d4ea55726f60dc505a1
-  languageName: node
-  linkType: hard
-
 "pify@npm:5.0.0":
   version: 5.0.0
   resolution: "pify@npm:5.0.0"
@@ -11873,7 +11764,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"semver@npm:2 || 3 || 4 || 5, semver@npm:^5.5.0, semver@npm:^5.6.0":
+"semver@npm:2 || 3 || 4 || 5, semver@npm:^5.6.0":
   version: 5.7.2
   resolution: "semver@npm:5.7.2"
   bin:
@@ -12071,15 +11962,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"shebang-command@npm:^1.2.0":
-  version: 1.2.0
-  resolution: "shebang-command@npm:1.2.0"
-  dependencies:
-    shebang-regex: "npm:^1.0.0"
-  checksum: 10c0/7b20dbf04112c456b7fc258622dafd566553184ac9b6938dd30b943b065b21dabd3776460df534cc02480db5e1b6aec44700d985153a3da46e7db7f9bd21326d
-  languageName: node
-  linkType: hard
-
 "shebang-command@npm:^2.0.0":
   version: 2.0.0
   resolution: "shebang-command@npm:2.0.0"
@@ -12089,13 +11971,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"shebang-regex@npm:^1.0.0":
-  version: 1.0.0
-  resolution: "shebang-regex@npm:1.0.0"
-  checksum: 10c0/9abc45dee35f554ae9453098a13fdc2f1730e525a5eb33c51f096cc31f6f10a4b38074c1ebf354ae7bffa7229506083844008dfc3bb7818228568c0b2dc1fff2
-  languageName: node
-  linkType: hard
-
 "shebang-regex@npm:^3.0.0":
   version: 3.0.0
   resolution: "shebang-regex@npm:3.0.0"
@@ -12103,7 +11978,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"shell-quote@npm:^1.6.1, shell-quote@npm:^1.8.3":
+"shell-quote@npm:^1.8.3":
   version: 1.8.3
   resolution: "shell-quote@npm:1.8.3"
   checksum: 10c0/bee87c34e1e986cfb4c30846b8e6327d18874f10b535699866f368ade11ea4ee45433d97bf5eada22c4320c27df79c3a6a7eb1bf3ecfc47f2c997d9e5e2672fd
@@ -12533,18 +12408,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"string.prototype.padend@npm:^3.0.0":
-  version: 3.1.6
-  resolution: "string.prototype.padend@npm:3.1.6"
-  dependencies:
-    call-bind: "npm:^1.0.7"
-    define-properties: "npm:^1.2.1"
-    es-abstract: "npm:^1.23.2"
-    es-object-atoms: "npm:^1.0.0"
-  checksum: 10c0/8f2c8c1f3db1efcdc210668c80c87f2cea1253d6029ff296a172b5e13edc9adebeed4942d023de8d31f9b13b69f3f5d73de7141959b1f09817fba5f527e83be1
-  languageName: node
-  linkType: hard
-
 "string.prototype.trim@npm:^1.2.10":
   version: 1.2.10
   resolution: "string.prototype.trim@npm:1.2.10"
@@ -12672,15 +12535,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"supports-color@npm:^5.3.0":
-  version: 5.5.0
-  resolution: "supports-color@npm:5.5.0"
-  dependencies:
-    has-flag: "npm:^3.0.0"
-  checksum: 10c0/6ae5ff319bfbb021f8a86da8ea1f8db52fac8bd4d499492e30ec17095b58af11f0c55f8577390a749b1c4dde691b6a0315dab78f5f54c9b3d83f8fb5905c1c05
-  languageName: node
-  linkType: hard
-
 "supports-color@npm:^7.1.0":
   version: 7.2.0
   resolution: "supports-color@npm:7.2.0"
@@ -13903,7 +13757,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"which@npm:^1.2.1, which@npm:^1.2.9":
+"which@npm:^1.2.1":
   version: 1.3.1
   resolution: "which@npm:1.3.1"
   dependencies: