diff --git a/packages/sdk/browser/contract-tests/entity/src/makeLogger.ts b/packages/sdk/browser/contract-tests/entity/src/makeLogger.ts
index 6d09061d0..a8cf9f165 100644
--- a/packages/sdk/browser/contract-tests/entity/src/makeLogger.ts
+++ b/packages/sdk/browser/contract-tests/entity/src/makeLogger.ts
@@ -2,19 +2,19 @@ import { LDLogger } from '@launchdarkly/js-client-sdk';
 
 export function makeLogger(tag: string): LDLogger {
   return {
-    debug(message, ...args: any[]) {
+    debug(message: any, ...args: any[]) {
       // eslint-disable-next-line no-console
       console.debug(`${new Date().toISOString()} [${tag}]: ${message}`, ...args);
     },
-    info(message, ...args: any[]) {
+    info(message: any, ...args: any[]) {
       // eslint-disable-next-line no-console
       console.info(`${new Date().toISOString()} [${tag}]: ${message}`, ...args);
     },
-    warn(message, ...args: any[]) {
+    warn(message: any, ...args: any[]) {
       // eslint-disable-next-line no-console
       console.warn(`${new Date().toISOString()} [${tag}]: ${message}`, ...args);
     },
-    error(message, ...args: any[]) {
+    error(message: any, ...args: any[]) {
       // eslint-disable-next-line no-console
       console.error(`${new Date().toISOString()} [${tag}]: ${message}`, ...args);
     },
diff --git a/packages/sdk/browser/package.json b/packages/sdk/browser/package.json
index d28c12c3e..18f934fe2 100644
--- a/packages/sdk/browser/package.json
+++ b/packages/sdk/browser/package.json
@@ -16,25 +16,38 @@
     "feature management",
     "sdk"
   ],
+  "type": "module",
+  "main": "./dist/index.cjs",
+  "module": "./dist/index.js",
+  "types": "./dist/index.d.ts",
   "exports": {
     ".": {
-      "types": "./dist/src/index.d.ts",
-      "require": "./dist/index.cjs.js",
-      "import": "./dist/index.es.js"
+      "require": {
+        "types": "./dist/index.d.cts",
+        "require": "./dist/index.cjs"
+      },
+      "import": {
+        "types": "./dist/index.d.ts",
+        "import": "./dist/index.js"
+      }
     },
     "./compat": {
-      "types": "./dist/src/compat/index.d.ts",
-      "require": "./dist/compat.cjs.js",
-      "import": "./dist/compat.es.js"
+      "require": {
+        "types": "./dist/compat.d.cts",
+        "require": "./dist/compat.cjs"
+      },
+      "import": {
+        "types": "./dist/compat.d.ts",
+        "import": "./dist/compat.js"
+      }
     }
   },
-  "type": "module",
   "files": [
     "dist"
   ],
   "scripts": {
     "clean": "rimraf dist",
-    "build": "tsc --noEmit && rollup -c rollup.config.js",
+    "build": "tsup",
     "lint": "eslint . --ext .ts,.tsx",
     "prettier": "prettier --write '**/*.@(js|ts|tsx|json|css)' --ignore-path ../../../.prettierignore",
     "test": "npx jest --runInBand",
@@ -46,11 +59,6 @@
   },
   "devDependencies": {
     "@jest/globals": "^29.7.0",
-    "@rollup/plugin-commonjs": "^25.0.0",
-    "@rollup/plugin-json": "^6.1.0",
-    "@rollup/plugin-node-resolve": "^15.0.2",
-    "@rollup/plugin-terser": "^0.4.3",
-    "@rollup/plugin-typescript": "^11.1.1",
     "@trivago/prettier-plugin-sort-imports": "^4.1.1",
     "@types/jest": "^29.5.11",
     "@typescript-eslint/eslint-plugin": "^6.20.0",
@@ -66,9 +74,8 @@
     "jest-environment-jsdom": "^29.7.0",
     "prettier": "^3.0.0",
     "rimraf": "^5.0.5",
-    "rollup": "^3.23.0",
-    "rollup-plugin-visualizer": "^5.12.0",
     "ts-jest": "^29.1.1",
+    "tsup": "^8.3.5",
     "typedoc": "0.25.0",
     "typescript": "^5.5.3"
   }
diff --git a/packages/sdk/browser/rollup.config.js b/packages/sdk/browser/rollup.config.js
deleted file mode 100644
index f1810e932..000000000
--- a/packages/sdk/browser/rollup.config.js
+++ /dev/null
@@ -1,56 +0,0 @@
-import common from '@rollup/plugin-commonjs';
-import json from '@rollup/plugin-json';
-import resolve from '@rollup/plugin-node-resolve';
-import terser from '@rollup/plugin-terser';
-import typescript from '@rollup/plugin-typescript';
-import { visualizer } from 'rollup-plugin-visualizer';
-
-const getSharedConfig = (format, extension) => ({
-  input: {
-    index: 'src/index.ts',
-    compat: 'src/compat/index.ts'
-  },
-  output:
-  {
-    format: format,
-    sourcemap: true,
-    dir: 'dist',
-    entryFileNames: '[name]' + extension
-  },
-});
-
-const terserOpts = {
-  mangle: {
-    properties: {
-      // Mangle class properties which start with an underscore.
-      regex: /^_/,
-      // Do not mangle '_meta', because this is part of our JSON
-      // data model.
-      reserved: ['_meta'],
-    },
-  },
-};
-
-export default [
-  {
-    ...getSharedConfig('es', '.es.js'),
-    plugins: [
-      typescript({
-        module: 'esnext',
-      }),
-      common({
-        transformMixedEsModules: true,
-        esmExternals: true,
-      }),
-      resolve(),
-      terser(terserOpts),
-      json(),
-      // The 'sourcemap' option allows using the minified size, not the size before minification.
-      visualizer({ sourcemap: true }),
-    ],
-  },
-  {
-    ...getSharedConfig('cjs', '.cjs.js'),
-    plugins: [typescript(), common(), resolve(), terser(terserOpts), json()],
-  },
-];
diff --git a/packages/sdk/browser/tsconfig.json b/packages/sdk/browser/tsconfig.json
index 929948785..7306c5b0c 100644
--- a/packages/sdk/browser/tsconfig.json
+++ b/packages/sdk/browser/tsconfig.json
@@ -8,18 +8,17 @@
     "moduleResolution": "node",
     "noImplicitOverride": true,
     "resolveJsonModule": true,
-    // Uses "." so it can load package.json.
     "rootDir": ".",
     "outDir": "dist",
     "skipLibCheck": true,
-    // enables importers to jump to source
-    "sourceMap": true,
+    "sourceMap": false,
     "strict": true,
     "stripInternal": true,
     "target": "ES2017",
     "types": ["node", "jest"],
     "allowJs": true
   },
+  "include": ["src"],
   "exclude": [
     "vite.config.ts",
     "__tests__",
@@ -27,9 +26,9 @@
     "docs",
     "example",
     "node_modules",
-    "contract-tests",
     "babel.config.js",
-    "jestSetupFile.ts",
+    "setup-jest.js",
+    "rollup.config.js",
     "**/*.test.ts*"
   ]
 }
diff --git a/packages/sdk/browser/tsup.config.ts b/packages/sdk/browser/tsup.config.ts
new file mode 100644
index 000000000..56a856d87
--- /dev/null
+++ b/packages/sdk/browser/tsup.config.ts
@@ -0,0 +1,27 @@
+// It is a dev dependency and the linter doesn't understand.
+// eslint-disable-next-line import/no-extraneous-dependencies
+import { defineConfig } from 'tsup';
+
+export default defineConfig({
+  entry: {
+    index: 'src/index.ts',
+    compat: 'src/compat/index.ts',
+  },
+  minify: true,
+  format: ['esm', 'cjs'],
+  splitting: false,
+  sourcemap: false,
+  clean: true,
+  noExternal: ['@launchdarkly/js-sdk-common', '@launchdarkly/js-client-sdk-common'],
+  dts: true,
+  metafile: true,
+  esbuildOptions(opts) {
+    // This would normally be `^_(?!meta|_)`, but go doesn't support negative look-ahead assertions,
+    // so we need to craft something that works without it.
+    // So start of line followed by a character that isn't followed by m or underscore, but we
+    // want other things that do start with m, so we need to progressively handle more characters
+    // of meta with exclusions.
+    // eslint-disable-next-line no-param-reassign
+    opts.mangleProps = /^_([^m|_]|m[^e]|me[^t]|met[^a])/;
+  },
+});