diff --git a/packages/pglite/src/fs/tarUtils.ts b/packages/pglite/src/fs/tarUtils.ts
index 0c80d43e..b87c6539 100644
--- a/packages/pglite/src/fs/tarUtils.ts
+++ b/packages/pglite/src/fs/tarUtils.ts
@@ -2,13 +2,20 @@ import { tar, untar, type TarFile, REGTYPE, DIRTYPE } from "tinytar";
 import { FS } from "../postgres.js";
 import { PGDATA } from "./index.js";
 
-export async function dumpTar(FS: FS, dbname?: string): Promise<File> {
+export async function dumpTar(FS: FS, dbname?: string): Promise<File | Blob> {
   const tarball = createTarball(FS, PGDATA);
   const [compressed, zipped] = await maybeZip(tarball);
   const filename = (dbname || "pgdata") + (zipped ? ".tar.gz" : ".tar");
-  return new File([compressed], filename, {
-    type: zipped ? "application/x-gtar" : "application/x-tar",
-  });
+  const type = zipped ? "application/x-gzip" : "application/x-tar";
+  if (typeof File !== "undefined") {
+    return new File([compressed], filename, {
+      type,
+    });
+  } else {
+    return new Blob([compressed], {
+      type,
+    });
+  }
 }
 
 const compressedMimeTypes = [
@@ -20,7 +27,8 @@ const compressedMimeTypes = [
 
 export async function loadTar(FS: FS, file: File | Blob): Promise<void> {
   let tarball = new Uint8Array(await file.arrayBuffer());
-  const filename = file instanceof File ? file.name : undefined;
+  const filename =
+    typeof File !== "undefined" && file instanceof File ? file.name : undefined;
   const compressed =
     compressedMimeTypes.includes(file.type) ||
     filename?.endsWith(".tgz") ||
diff --git a/packages/pglite/src/fs/types.ts b/packages/pglite/src/fs/types.ts
index ed09167d..c3b6f0a7 100644
--- a/packages/pglite/src/fs/types.ts
+++ b/packages/pglite/src/fs/types.ts
@@ -25,7 +25,7 @@ export interface Filesystem {
   /**
    * Dump the PGDATA dir from the filesystem to a gziped tarball.
    */
-  dumpTar(FS: FS, dbname: string): Promise<File>;
+  dumpTar(FS: FS, dbname: string): Promise<File | Blob>;
 }
 
 export abstract class FilesystemBase implements Filesystem {
@@ -38,5 +38,5 @@ export abstract class FilesystemBase implements Filesystem {
   ): Promise<Partial<PostgresMod>>;
   async syncToFs(FS: FS) {}
   async initialSyncFs(mod: FS) {}
-  abstract dumpTar(mod: FS, dbname: string): Promise<File>;
+  abstract dumpTar(mod: FS, dbname: string): Promise<File | Blob>;
 }
diff --git a/packages/pglite/src/interface.ts b/packages/pglite/src/interface.ts
index 15f3c544..c2fa7976 100644
--- a/packages/pglite/src/interface.ts
+++ b/packages/pglite/src/interface.ts
@@ -90,7 +90,7 @@ export type PGliteInterface = {
     callback: (channel: string, payload: string) => void,
   ): () => void;
   offNotification(callback: (channel: string, payload: string) => void): void;
-  dumpDataDir(): Promise<File>;
+  dumpDataDir(): Promise<File | Blob>;
 };
 
 export type PGliteInterfaceExtensions<E> = E extends Extensions
diff --git a/packages/pglite/src/pglite.ts b/packages/pglite/src/pglite.ts
index 1885d482..679accf2 100644
--- a/packages/pglite/src/pglite.ts
+++ b/packages/pglite/src/pglite.ts
@@ -747,6 +747,7 @@ export class PGlite implements PGliteInterface {
 
   /**
    * Dump the PGDATA dir from the filesystem to a gziped tarball.
+   * @returns The tarball as a File object where available, and fallback to a Blob
    */
   async dumpDataDir() {
     let dbname = this.dataDir?.split("/").pop() ?? "pgdata";