diff --git a/app/api.js b/app/api.js
index 4101f9a8..7ec1341e 100644
--- a/app/api.js
+++ b/app/api.js
@@ -115,6 +115,7 @@ function listenForResponse(ws, canceller) {
           });
         }
       } catch (e) {
+        ws.close();
         canceller.cancelled = true;
         canceller.error = e;
         reject(e);
@@ -134,7 +135,6 @@ async function upload(
   const host = window.location.hostname;
   const port = window.location.port;
   const protocol = window.location.protocol === 'https:' ? 'wss:' : 'ws:';
-  const error = { cancelled: false };
   const ws = await asyncInitWebSocket(`${protocol}//${host}:${port}/api/ws`);
 
   try {
@@ -144,7 +144,7 @@ async function upload(
       authorization: `send-v1 ${verifierB64}`
     };
 
-    const responsePromise = listenForResponse(ws, error);
+    const responsePromise = listenForResponse(ws, canceller);
 
     ws.send(JSON.stringify(fileMeta));
 
@@ -154,17 +154,17 @@ async function upload(
     while (!state.done) {
       const buf = state.value;
       if (canceller.cancelled) {
-        throw new Error(0);
-      }
-      if (error.cancelled) {
-        throw new Error(error.error);
+        throw canceller.error;
       }
+
       ws.send(buf);
 
       onprogress([Math.min(streamInfo.fileSize, size), streamInfo.fileSize]);
       size += streamInfo.recordSize;
       state = await reader.read();
     }
+    const footer = new Uint8Array([0]);
+    ws.send(footer);
 
     const response = await responsePromise; //promise only fufills if response is good
     ws.close();
@@ -180,6 +180,7 @@ export function uploadWs(encrypted, info, metadata, verifierB64, onprogress) {
 
   return {
     cancel: function() {
+      canceller.error = new Error(0);
       canceller.cancelled = true;
     },
     result: upload(
diff --git a/server/routes/ws.js b/server/routes/ws.js
index ea81573c..f2f6250d 100644
--- a/server/routes/ws.js
+++ b/server/routes/ws.js
@@ -3,6 +3,7 @@ const storage = require('../storage');
 const config = require('../config');
 const mozlog = require('../log');
 const Limiter = require('../limiter');
+const Parser = require('../streamparser');
 const wsStream = require('websocket-stream/stream');
 
 const log = mozlog('send.upload');
@@ -45,7 +46,10 @@ module.exports = async function(ws, req) {
       const url = `${protocol}://${req.get('host')}/download/${newId}/`;
 
       const limiter = new Limiter(config.max_file_size);
-      fileStream = wsStream(ws, { binary: true }).pipe(limiter);
+      const parser = new Parser();
+      fileStream = wsStream(ws, { binary: true })
+        .pipe(limiter)
+        .pipe(parser);
       storage.set(newId, fileStream, meta);
 
       ws.send(
@@ -60,7 +64,7 @@ module.exports = async function(ws, req) {
       log.error('upload', e);
       ws.send(
         JSON.stringify({
-          error: 500
+          error: e === 'limit' ? 413 : 500
         })
       );
       ws.close();
diff --git a/server/streamparser.js b/server/streamparser.js
new file mode 100644
index 00000000..d7f7b110
--- /dev/null
+++ b/server/streamparser.js
@@ -0,0 +1,23 @@
+const { Transform } = require('stream');
+
+class StreamParser extends Transform {
+  constructor() {
+    super();
+    let res;
+    this.promise = new Promise(resolve => {
+      res = resolve;
+    });
+    this.res = res;
+  }
+
+  _transform(chunk, encoding, callback) {
+    if (chunk.byteLength === 1 && chunk[0] === 0) {
+      this.res();
+    } else {
+      this.push(chunk);
+    }
+    callback();
+  }
+}
+
+module.exports = StreamParser;