diff --git a/CHANGELOG.md b/CHANGELOG.md
index bb00c4b..c5030ca 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,8 @@
 # Changelog
 
+## 1.3.1-r4
+- Support writing base64 string data
+
 ## 1.3.1-r3
 - Added directory/file exists
 - Fix unit tests
diff --git a/src/io/file.js b/src/io/file.js
index 4bcb762..9cb1d7d 100644
--- a/src/io/file.js
+++ b/src/io/file.js
@@ -89,4 +89,20 @@ export default class file {
       this.thread_id
     );
   }
+
+  async write_base64(offset, base64_string) {
+    if (this.handle === null) {
+      return Promise.reject(
+        new Error("'write_base64()' failed: invalid handle")
+      );
+    }
+    return ops.write_base64_file(
+      this.conn,
+      this.handle,
+      this.remote_path,
+      offset,
+      base64_string,
+      this.thread_id
+    );
+  }
 }
diff --git a/src/ops/index.js b/src/ops/index.js
index b2ef48d..2898ac9 100644
--- a/src/ops/index.js
+++ b/src/ops/index.js
@@ -577,6 +577,41 @@ export const upload_file = async (
   }
 };
 
+export const write_base64_file = async (
+  conn,
+  handle,
+  remote_path,
+  offset,
+  base64_string,
+  optional_thread_id
+) => {
+  try {
+    const buffer = new Uint8Array(new TextEncoder().encode(base64_string));
+
+    const request = new packet();
+    request.encode_utf8(remote_path);
+    request.encode_ui64(buffer.length);
+    request.encode_buffer(buffer);
+    request.encode_ui64(offset);
+    request.encode_ui64(handle);
+
+    const response = await conn.send(
+      '::RemoteFUSEWriteBase64',
+      request,
+      optional_thread_id
+    );
+    response.decode_ui32(); // Service flags
+
+    const result = response.decode_i32();
+    if (result === buffer.length) {
+      return result;
+    }
+    return Promise.reject(new Error(`'write_base64_file' error: ${result}`));
+  } catch (err) {
+    return Promise.reject(new Error(`'write_base64_file' failed: ${err}`));
+  }
+};
+
 export const write_file = async (
   conn,
   handle,