diff --git a/CHANGELOG.md b/CHANGELOG.md
index ef73e92..dbb1aa6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Fixed
+
+- Resolves "Cannot use import statement outside of module" when building with SSR [#20](https://github.com/bugsnag/cuid/pull/20)
+
 ## [3.2.0] - 2025-02-18
 
 ### Changed
diff --git a/index.esm.js b/index.esm.mjs
similarity index 83%
rename from index.esm.js
rename to index.esm.mjs
index efa197b..eca112d 100644
--- a/index.esm.js
+++ b/index.esm.mjs
@@ -11,8 +11,8 @@
  */
 
 import fingerprint from '#fingerprint';
-import createCuid from './lib/cuid';
-import isCuid from './lib/is-cuid';
+import createCuid from './lib/cuid.mjs';
+import isCuid from './lib/is-cuid.mjs';
 
 const cuid = createCuid(fingerprint);
 
diff --git a/index.js b/index.mjs
similarity index 78%
rename from index.js
rename to index.mjs
index 4e16a47..013cd14 100644
--- a/index.js
+++ b/index.mjs
@@ -10,8 +10,8 @@
  * MIT License
  */
 
-import fingerprint from './lib/fingerprint';
-import createCuid from './lib/cuid';
+import fingerprint from './lib/fingerprint.mjs';
+import createCuid from './lib/cuid.mjs';
 
 const cuid = createCuid(fingerprint);
 
diff --git a/lib/cuid.js b/lib/cuid.mjs
similarity index 96%
rename from lib/cuid.js
rename to lib/cuid.mjs
index 2c539bf..bd64ae3 100644
--- a/lib/cuid.js
+++ b/lib/cuid.mjs
@@ -10,8 +10,8 @@
  * MIT License
  */
 
-import isCuid from './is-cuid';
-import pad from './pad';
+import isCuid from './is-cuid.mjs';
+import pad from './pad.mjs';
 
 export default function createCuid (fingerprint) {
     const blockSize = 4,
diff --git a/lib/fingerprint.browser.js b/lib/fingerprint.browser.mjs
similarity index 93%
rename from lib/fingerprint.browser.js
rename to lib/fingerprint.browser.mjs
index 6702307..d5f184e 100644
--- a/lib/fingerprint.browser.js
+++ b/lib/fingerprint.browser.mjs
@@ -1,4 +1,4 @@
-import pad from './pad';
+import pad from './pad.mjs';
 
 var env = typeof window === 'object' ? window : self;
 var globalCount = 0;
diff --git a/lib/fingerprint.js b/lib/fingerprint.mjs
similarity index 97%
rename from lib/fingerprint.js
rename to lib/fingerprint.mjs
index 5112538..8ebd9b7 100644
--- a/lib/fingerprint.js
+++ b/lib/fingerprint.mjs
@@ -1,4 +1,4 @@
-import pad from './pad';
+import pad from './pad.mjs';
 import os from 'os';
 
 function getHostname () {
diff --git a/lib/fingerprint.react-native.js b/lib/fingerprint.react-native.mjs
similarity index 83%
rename from lib/fingerprint.react-native.js
rename to lib/fingerprint.react-native.mjs
index 9668233..53cf3ca 100644
--- a/lib/fingerprint.react-native.js
+++ b/lib/fingerprint.react-native.mjs
@@ -1,4 +1,4 @@
-import pad from './pad';
+import pad from './pad.mjs';
 
 var globalCount = Object.keys(global);
 var clientId = pad(globalCount.toString(36), 4);
diff --git a/lib/is-cuid.js b/lib/is-cuid.mjs
similarity index 100%
rename from lib/is-cuid.js
rename to lib/is-cuid.mjs
diff --git a/lib/pad.js b/lib/pad.mjs
similarity index 100%
rename from lib/pad.js
rename to lib/pad.mjs
diff --git a/package.json b/package.json
index b2b3d2e..7499ac6 100644
--- a/package.json
+++ b/package.json
@@ -10,18 +10,20 @@
   "types": "cuid.d.ts",
   "exports": {
     ".": {
-      "import": "./index.esm.js",
+      "import": "./index.esm.mjs",
       "require": "./dist/index.js"
     },
     "./lib/fingerprint": {
-      "browser": "./lib/fingerprint.browser.js",
-      "node": "./lib/fingerprint.js"
+      "browser": "./lib/fingerprint.browser.mjs",
+      "node": "./lib/fingerprint.mjs",
+      "default": "./lib/fingerprint.react-native.mjs"
     }
   },
   "imports": {
     "#fingerprint": {
-      "browser": "./lib/fingerprint.browser.js",
-      "node": "./lib/fingerprint.js"
+      "browser": "./lib/fingerprint.browser.mjs",
+      "node": "./lib/fingerprint.mjs",
+      "default": "./lib/fingerprint.react-native.mjs"
     }
   },
   "browser": {
@@ -45,7 +47,7 @@
     "lib",
     "dist",
     "cuid.d.ts",
-    "index.esm.js"
+    "index.esm.mjs"
   ],
   "license": "MIT",
   "devDependencies": {
@@ -65,7 +67,7 @@
   "scripts": {
     "prebuild": "rm -rf dist",
     "build": "rollup -c",
-    "lint": "eslint index.js lib test",
+    "lint": "eslint index.mjs index.esm.mjs lib test",
     "test": "npm run lint && npm run test:server && npm run test:browser",
     "test:browser": "karma start test/karma.conf.js",
     "test:server": "jasmine test/**/*.js",
diff --git a/rollup.config.mjs b/rollup.config.mjs
index efc0c0d..a78b7ac 100644
--- a/rollup.config.mjs
+++ b/rollup.config.mjs
@@ -3,6 +3,7 @@ const sharedOutput = {
     dir: 'dist',
     preserveModules: true,
     exports: 'default',
+    entryFileNames: '[name].js',
     generatedCode: {
         preset: 'es2015'
     }
@@ -11,18 +12,18 @@ const sharedOutput = {
 export default [
     {
         external: ['os'],
-        input: 'index.js',
+        input: 'index.mjs',
         output: sharedOutput
     },
     {
-        input: 'lib/fingerprint.browser.js',
+        input: 'lib/fingerprint.browser.mjs',
         output: {
             ...sharedOutput,
             dir: 'dist/lib'
         }
     },
     {
-        input: 'lib/fingerprint.react-native.js',
+        input: 'lib/fingerprint.react-native.mjs',
         output: {
             ...sharedOutput,
             dir: 'dist/lib'