diff --git a/src/apply-style.ts b/src/apply-style.ts
index 5c58728d..c36a04e5 100644
--- a/src/apply-style.ts
+++ b/src/apply-style.ts
@@ -1,4 +1,4 @@
-import type { Options } from './types'
+import type { Options } from './types.js'
 
 export function applyStyle<T extends HTMLElement>(
   node: T,
diff --git a/src/clone-node.ts b/src/clone-node.ts
index 5dfcd117..90ad0b6c 100644
--- a/src/clone-node.ts
+++ b/src/clone-node.ts
@@ -1,13 +1,13 @@
-import type { Options } from './types'
-import { clonePseudoElements } from './clone-pseudos'
+import type { Options } from './types.js'
+import { clonePseudoElements } from './clone-pseudos.js'
 import {
   createImage,
   toArray,
   isInstanceOfElement,
   getStyleProperties,
-} from './util'
-import { getMimeType } from './mimes'
-import { resourceToDataURL } from './dataurl'
+} from './util.js'
+import { getMimeType } from './mimes.js'
+import { resourceToDataURL } from './dataurl.js'
 
 async function cloneCanvasElement(canvas: HTMLCanvasElement) {
   const dataURL = canvas.toDataURL()
diff --git a/src/clone-pseudos.ts b/src/clone-pseudos.ts
index b5af1edc..9f644aa6 100644
--- a/src/clone-pseudos.ts
+++ b/src/clone-pseudos.ts
@@ -1,5 +1,5 @@
-import type { Options } from './types'
-import { uuid, getStyleProperties } from './util'
+import type { Options } from './types.js'
+import { uuid, getStyleProperties } from './util.js'
 
 type Pseudo = ':before' | ':after'
 
diff --git a/src/dataurl.ts b/src/dataurl.ts
index 13bc8b43..0b8c169c 100644
--- a/src/dataurl.ts
+++ b/src/dataurl.ts
@@ -1,4 +1,4 @@
-import { Options } from './types'
+import { Options } from './types.js'
 
 function getContentFromDataUrl(dataURL: string) {
   return dataURL.split(/,/)[1]
diff --git a/src/embed-images.ts b/src/embed-images.ts
index 0d7b51ad..622295b7 100644
--- a/src/embed-images.ts
+++ b/src/embed-images.ts
@@ -1,8 +1,8 @@
-import { Options } from './types'
-import { embedResources } from './embed-resources'
-import { toArray, isInstanceOfElement } from './util'
-import { isDataUrl, resourceToDataURL } from './dataurl'
-import { getMimeType } from './mimes'
+import { Options } from './types.js'
+import { embedResources } from './embed-resources.js'
+import { toArray, isInstanceOfElement } from './util.js'
+import { isDataUrl, resourceToDataURL } from './dataurl.js'
+import { getMimeType } from './mimes.js'
 
 async function embedProp(
   propName: string,
diff --git a/src/embed-resources.ts b/src/embed-resources.ts
index bed8b373..43dfda6c 100644
--- a/src/embed-resources.ts
+++ b/src/embed-resources.ts
@@ -1,7 +1,7 @@
-import { Options } from './types'
-import { resolveUrl } from './util'
-import { getMimeType } from './mimes'
-import { isDataUrl, makeDataUrl, resourceToDataURL } from './dataurl'
+import { Options } from './types.js'
+import { resolveUrl } from './util.js'
+import { getMimeType } from './mimes.js'
+import { isDataUrl, makeDataUrl, resourceToDataURL } from './dataurl.js'
 
 const URL_REGEX = /url\((['"]?)([^'"]+?)\1\)/g
 const URL_WITH_FORMAT_REGEX = /url\([^)]+\)\s*format\((["']?)([^"']+)\1\)/g
diff --git a/src/embed-webfonts.ts b/src/embed-webfonts.ts
index a84a699d..f5e1b1f8 100644
--- a/src/embed-webfonts.ts
+++ b/src/embed-webfonts.ts
@@ -1,7 +1,7 @@
-import type { Options } from './types'
-import { toArray } from './util'
-import { fetchAsDataURL } from './dataurl'
-import { shouldEmbed, embedResources } from './embed-resources'
+import type { Options } from './types.js'
+import { toArray } from './util.js'
+import { fetchAsDataURL } from './dataurl.js'
+import { shouldEmbed, embedResources } from './embed-resources.js'
 
 interface Metadata {
   url: string
diff --git a/src/index.ts b/src/index.ts
index 2de59a30..8d265179 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,8 +1,8 @@
-import { Options } from './types'
-import { cloneNode } from './clone-node'
-import { embedImages } from './embed-images'
-import { applyStyle } from './apply-style'
-import { embedWebFonts, getWebFontCSS } from './embed-webfonts'
+import { Options } from './types.js'
+import { cloneNode } from './clone-node.js'
+import { embedImages } from './embed-images.js'
+import { applyStyle } from './apply-style.js'
+import { embedWebFonts, getWebFontCSS } from './embed-webfonts.js'
 import {
   getImageSize,
   getPixelRatio,
@@ -10,7 +10,7 @@ import {
   canvasToBlob,
   nodeToDataURL,
   checkCanvasDimensions,
-} from './util'
+} from './util.js'
 
 export async function toSvg<T extends HTMLElement>(
   node: T,
diff --git a/src/util.ts b/src/util.ts
index 3d430c8f..38ac2986 100644
--- a/src/util.ts
+++ b/src/util.ts
@@ -1,4 +1,4 @@
-import type { Options } from './types'
+import type { Options } from './types.js'
 
 export function resolveUrl(url: string, baseUrl: string | null): string {
   // url is absolute already