diff --git a/packages/express-partial-content/src/Content.ts b/packages/express-partial-content/src/Content.ts
index 93fd77052..bba8fed24 100644
--- a/packages/express-partial-content/src/Content.ts
+++ b/packages/express-partial-content/src/Content.ts
@@ -1,4 +1,4 @@
-import { Range } from "./Range";
+import type { Range } from "./Range.js";
 import { Stream } from "stream";
 export interface Content {
   /**
diff --git a/packages/express-partial-content/src/ContentProvider.ts b/packages/express-partial-content/src/ContentProvider.ts
index a27534afa..6fb2648c3 100644
--- a/packages/express-partial-content/src/ContentProvider.ts
+++ b/packages/express-partial-content/src/ContentProvider.ts
@@ -1,5 +1,5 @@
-import { Request } from "express";
-import { Content } from "./Content";
+import type { Request } from "express";
+import type { Content } from "./Content.js";
 /**
  * @type {function (Request): Promise<Content>}
  */
diff --git a/packages/express-partial-content/src/createPartialContentHandler.ts b/packages/express-partial-content/src/createPartialContentHandler.ts
index 7562bc9b3..b7fee0d42 100644
--- a/packages/express-partial-content/src/createPartialContentHandler.ts
+++ b/packages/express-partial-content/src/createPartialContentHandler.ts
@@ -1,9 +1,9 @@
-import { Request, Response } from "express";
-import { parseRangeHeader } from "./parseRangeHeader";
-import { RangeParserError } from "./RangeParserError";
-import { Logger } from "./Logger";
-import { ContentProvider } from "./ContentProvider";
-import { ContentDoesNotExistError } from "./ContentDoesNotExistError";
+import type { Request, Response } from "express";
+import { parseRangeHeader } from "./parseRangeHeader.js";
+import { RangeParserError } from "./RangeParserError.js";
+import type { Logger } from "./Logger.js";
+import type { ContentProvider } from "./ContentProvider.js";
+import { ContentDoesNotExistError } from "./ContentDoesNotExistError.js";
 import {
   getRangeHeader,
   setContentRangeHeader,
@@ -12,7 +12,7 @@ import {
   setAcceptRangesHeader,
   setContentLengthHeader,
   setCacheControlHeaderNoCache
-} from "./utils";
+} from "./utils.js";
 export function createPartialContentHandler(contentProvider: ContentProvider, logger: Logger) {
   return async function handler(req: Request, res: Response) {
     let content;
diff --git a/packages/express-partial-content/src/index.ts b/packages/express-partial-content/src/index.ts
index d90b52cfa..445d6027f 100644
--- a/packages/express-partial-content/src/index.ts
+++ b/packages/express-partial-content/src/index.ts
@@ -1,6 +1,6 @@
-export * from "./Content";
-export * from "./ContentDoesNotExistError";
-export * from "./ContentProvider";
-export * from "./createPartialContentHandler";
-export * from "./Logger";
-export * from "./Range";
+export * from "./Content.js";
+export * from "./ContentDoesNotExistError.js";
+export * from "./ContentProvider.js";
+export * from "./createPartialContentHandler.js";
+export * from "./Logger.js";
+export * from "./Range.js";
diff --git a/packages/express-partial-content/src/parseRangeHeader.ts b/packages/express-partial-content/src/parseRangeHeader.ts
index dc97a41cc..284ecdfc2 100644
--- a/packages/express-partial-content/src/parseRangeHeader.ts
+++ b/packages/express-partial-content/src/parseRangeHeader.ts
@@ -1,6 +1,6 @@
-import { Logger } from "./Logger";
-import { RangeParserError } from "./RangeParserError";
-import { Range } from "./Range";
+import type { Logger } from "./Logger.js";
+import { RangeParserError } from "./RangeParserError.js";
+import type { Range } from "./Range.js";
 
 const rangeRegEx = /bytes=([0-9]*)-([0-9]*)/;
 
diff --git a/packages/express-partial-content/src/utils.ts b/packages/express-partial-content/src/utils.ts
index 503694522..0aa4fdf08 100644
--- a/packages/express-partial-content/src/utils.ts
+++ b/packages/express-partial-content/src/utils.ts
@@ -1,5 +1,5 @@
-import { Request, Response } from "express";
-import { Range } from "./Range";
+import type { Request, Response } from "express";
+import type { Range } from "./Range.js";
 export const getHeader = (name: string, req: Request) => req.headers[name];
 export const getRangeHeader = getHeader.bind(null, "range");
 export const setHeader = (name: string, value: string, res: Response) => res.setHeader(name, value);