diff --git a/.prettierrc.json b/.prettierrc.json
new file mode 100644
index 0000000..fca24df
--- /dev/null
+++ b/.prettierrc.json
@@ -0,0 +1,6 @@
+{
+  "trailingComma": "none",
+  "tabWidth": 2,
+  "semi": true,
+  "singleQuote": false
+}
diff --git a/src/upload.js b/src/upload.js
index 5c00501..a731c1d 100644
--- a/src/upload.js
+++ b/src/upload.js
@@ -125,7 +125,11 @@ export default class Upload extends EventEmitter {
     this.options = opts;
     this.filename = filename;
     this.handle = createHandle(filename);
-    this.metadata = createMetaData(filename, chunkCount);
+    this.metadata = createMetaData({
+      fileName: filename,
+      numberOfChunks: chunkCount,
+      custom: opts.custom
+    });
     this.genesisHash = genesisHash(this.handle);
     this.key = bytesFromHandle(this.handle);
     this.numberOfChunks = totalChunks;
diff --git a/src/utils/file-processor.js b/src/utils/file-processor.js
index 868752e..fdcc26b 100644
--- a/src/utils/file-processor.js
+++ b/src/utils/file-processor.js
@@ -1,10 +1,11 @@
-export function createMetaData(fileName, numberOfChunks) {
+export function createMetaData({ fileName, numberOfChunks, custom }) {
   const fileExtension = fileName.split(".").pop();
 
   const meta = {
     fileName: fileName.substr(0, 500),
     ext: fileExtension,
-    numberOfChunks
+    numberOfChunks,
+    custom: custom || {}
   };
 
   return meta;
diff --git a/src/utils/file-processor.test.js b/src/utils/file-processor.test.js
new file mode 100644
index 0000000..f8f99c9
--- /dev/null
+++ b/src/utils/file-processor.test.js
@@ -0,0 +1,28 @@
+import * as fileProcessor from "./file-processor.js";
+
+test("createMetaData without custom params", () => {
+  const fileName = "foobar.txt";
+  const numberOfChunks = 10;
+
+  expect(fileProcessor.createMetaData({ fileName, numberOfChunks })).toEqual({
+    fileName: "foobar.txt",
+    ext: "txt",
+    numberOfChunks,
+    custom: {}
+  });
+});
+
+test("createMetaData with custom params", () => {
+  const fileName = "foobar.txt";
+  const numberOfChunks = 10;
+  const custom = { foo: "bar" };
+
+  expect(
+    fileProcessor.createMetaData({ fileName, numberOfChunks, custom })
+  ).toEqual({
+    fileName: "foobar.txt",
+    ext: "txt",
+    numberOfChunks,
+    custom
+  });
+});