diff --git a/package-lock.json b/package-lock.json
index 6c5dfe5c..2a275626 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1884,6 +1884,12 @@
       "integrity": "sha512-F5DIZ36YVLE+PN+Zwws4kJogq47hNgX3Nx6WyDJ3kcplxyke3XIzB8uK5n/Lpm1HBsbGzd6nmGehL8cPekP+Tg==",
       "dev": true
     },
+    "@types/wicg-file-system-access": {
+      "version": "2020.9.4",
+      "resolved": "https://registry.npmjs.org/@types/wicg-file-system-access/-/wicg-file-system-access-2020.9.4.tgz",
+      "integrity": "sha512-o43jUljwP0ZrQ927mPjGdJaBMfS12nf3VPj6Z52fMucxILrSs8tnfLbMDSn6cP3hrrLChc3SYneeEvecknNVtA==",
+      "dev": true
+    },
     "@vitejs/plugin-react": {
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/@vitejs/plugin-react/-/plugin-react-1.0.1.tgz",
diff --git a/package.json b/package.json
index 60bc8cdd..28e1c836 100644
--- a/package.json
+++ b/package.json
@@ -34,6 +34,7 @@
     "@danmarshall/deckgl-typings": "^4.3.10",
     "@types/node": "^14.14.5",
     "@types/react-dom": "^17.0.0",
+    "@types/wicg-file-system-access": "^2020.9.4",
     "@vitejs/plugin-react": "^1.0.1",
     "prettier": "^2.2.0",
     "typescript": "^4.4.3",
diff --git a/src/fsstore.ts b/src/fsstore.ts
new file mode 100644
index 00000000..824553c6
--- /dev/null
+++ b/src/fsstore.ts
@@ -0,0 +1,45 @@
+import type { AsyncStore } from 'zarr/types/storage/types';
+import { KeyError } from 'zarr';
+
+async function getFileHandle(root: FileSystemDirectoryHandle, key: string) {
+  const dirs = key.split('/');
+  const fname = dirs.pop()!;
+  for (const dir of dirs) {
+    root = await root.getDirectoryHandle(dir);
+  }
+  return root.getFileHandle(fname);
+}
+
+export class FileSystemStore implements AsyncStore<ArrayBuffer> {
+  constructor(public root: FileSystemDirectoryHandle) {}
+
+  static async fromDirectoryPicker() {
+    return new FileSystemStore(await window.showDirectoryPicker());
+  }
+
+  async getItem(key: string) {
+    const fileHandle = await getFileHandle(this.root, key).catch((_) => {
+      throw new KeyError(key);
+    });
+    const file = await fileHandle.getFile();
+    return file.arrayBuffer();
+  }
+
+  containsItem(key: string) {
+    return getFileHandle(this.root, key)
+      .then((_) => true)
+      .catch((_) => false);
+  }
+
+  keys() {
+    return Promise.resolve([]);
+  }
+
+  deleteItem(key: string): never {
+    throw new Error('deleteItem not implemented');
+  }
+
+  setItem(key: string, value: ArrayBuffer): never {
+    throw new Error('setItem not implemented');
+  }
+}
diff --git a/tsconfig.json b/tsconfig.json
index 731b86d7..7da5d78f 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -17,7 +17,8 @@
       "zarr": ["node_modules/zarr"]
     },
     "types": [
-      "vite-plugin-pwa/client"
+      "vite-plugin-pwa/client",
+      "@types/wicg-file-system-access"
     ]
   }
 }