diff --git a/app.js b/app.js
index da1c8e9c0..d37a883c8 100644
--- a/app.js
+++ b/app.js
@@ -74,10 +74,6 @@ metrics.setupCustomPrometheusMetrics()
 
 // socket io
 const io = require('socket.io')(server, { cookie: false })
-io.engine.ws = new (require('ws').Server)({
-  noServer: true,
-  perMessageDeflate: false
-})
 
 // others
 const realtime = require('./lib/realtime.js')
diff --git a/package.json b/package.json
index 41e213f10..1724a4368 100644
--- a/package.json
+++ b/package.json
@@ -103,7 +103,6 @@
     "uuid": "^8.0.0",
     "validator": "^13.0.0",
     "winston": "^3.1.0",
-    "ws": "^7.4.4",
     "xss": "^1.0.3"
   },
   "resolutions": {
diff --git a/yarn.lock b/yarn.lock
index 8b8e6e92f..566a191bc 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1044,7 +1044,6 @@
 
 "Idle.Js@git+https://github.com/shawnmclean/Idle.js":
   version "0.0.1"
-  uid "2b57cc6e49d177b7ddce0cca00ef5cbe07453541"
   resolved "git+https://github.com/shawnmclean/Idle.js#2b57cc6e49d177b7ddce0cca00ef5cbe07453541"
 
 JSV@^4.0.x:
@@ -1062,7 +1061,7 @@ abcjs@5.10.3:
   resolved "https://registry.yarnpkg.com/abcjs/-/abcjs-5.10.3.tgz#294702140ec1caa292859ba9d2af0452f7e9e046"
   integrity sha512-YGmW4CUWd7T2/HqZa/SQOTE+lXg7Z68HwwpJhHJBvdHqLi1uLCiYva1ZRGhB/MPyl1QKqJMfF+LQ1jGAEK69XQ==
   dependencies:
-    midi "git+https://github.com/paulrosen/MIDI.js.git#abcjs"
+    midi "https://github.com/paulrosen/MIDI.js.git#abcjs"
 
 abcjs@5.11.0:
   version "5.11.0"
@@ -1070,7 +1069,7 @@ abcjs@5.11.0:
   integrity sha512-kLehHwwttcTCVhKQaDkmqYbWBLAWmfyzYSbUQoEDAOTOX5RzDGakX8tXpzlsNHw6Lh8W8odZw44e0siwbG4TKA==
   dependencies:
     abcjs "5.10.3"
-    midi "git+https://github.com/paulrosen/MIDI.js.git#abcjs"
+    midi "https://github.com/paulrosen/MIDI.js.git#abcjs"
 
 abcjs@5.12.0:
   version "5.12.0"
@@ -1078,7 +1077,7 @@ abcjs@5.12.0:
   integrity sha512-pvi7SjOAKT7cRyRtywUSwYB0SNtRHKLxZUZ9Oc4E+nvpBHr8Z2/M9Pfyv3oIaiEpxlWTFK+B/H5t/DckiNFgpg==
   dependencies:
     abcjs "5.11.0"
-    midi "git+https://github.com/paulrosen/MIDI.js.git#abcjs"
+    midi "https://github.com/paulrosen/MIDI.js.git#abcjs"
 
 abort-controller@^3.0.0:
   version "3.0.0"
@@ -2836,7 +2835,6 @@ code-point-at@^1.0.0:
 
 "codemirror@git+https://github.com/hedgedoc/CodeMirror.git":
   version "5.58.2"
-  uid f780b569b3717cdff4c8507538cc63101bfa02e1
   resolved "git+https://github.com/hedgedoc/CodeMirror.git#f780b569b3717cdff4c8507538cc63101bfa02e1"
 
 collection-visit@^1.0.0:
@@ -3842,7 +3840,6 @@ detect-libc@^1.0.2:
 
 "diff-match-patch@git+https://github.com/hackmdio/diff-match-patch.git":
   version "1.1.1"
-  uid c2f8fb9d69aa9490b764850aa86ba442c93ccf78
   resolved "git+https://github.com/hackmdio/diff-match-patch.git#c2f8fb9d69aa9490b764850aa86ba442c93ccf78"
 
 diff@5.0.0:
@@ -6341,7 +6338,6 @@ js-cookie@3.0.0:
 
 "js-sequence-diagrams@git+https://github.com/hedgedoc/js-sequence-diagrams.git":
   version "2.0.1"
-  uid bda0e49b6c2754f3c7158b1dfb9ccf26efc24b39
   resolved "git+https://github.com/hedgedoc/js-sequence-diagrams.git#bda0e49b6c2754f3c7158b1dfb9ccf26efc24b39"
   dependencies:
     lodash "4.17.x"
@@ -6978,7 +6974,6 @@ lutim@^1.0.2:
 
 "lz-string@git+https://github.com/hackmdio/lz-string.git":
   version "1.4.4"
-  uid efd1f64676264d6d8871b01f4f375fc6ef4f9022
   resolved "git+https://github.com/hackmdio/lz-string.git#efd1f64676264d6d8871b01f4f375fc6ef4f9022"
 
 make-dir@^1.0.0:
@@ -7283,7 +7278,6 @@ messageformat@^2.3.0:
 
 "meta-marked@git+https://github.com/hedgedoc/meta-marked":
   version "0.4.5"
-  uid bf2c9646a681a27200d36c6744ce8d23bbb3fc86
   resolved "git+https://github.com/hedgedoc/meta-marked#bf2c9646a681a27200d36c6744ce8d23bbb3fc86"
   dependencies:
     js-yaml "~4.1.0"
@@ -7532,7 +7526,6 @@ micromatch@^4.0.4:
 
 "midi@git+https://github.com/paulrosen/MIDI.js.git#abcjs":
   version "0.4.2"
-  uid e593ffef81a0350f99448e3ab8111957145ff6b2
   resolved "git+https://github.com/paulrosen/MIDI.js.git#e593ffef81a0350f99448e3ab8111957145ff6b2"
 
 miller-rabin@^4.0.0:
@@ -12366,11 +12359,6 @@ write-file-atomic@^2.3.0:
     imurmurhash "^0.1.4"
     signal-exit "^3.0.2"
 
-ws@^7.4.4:
-  version "7.5.3"
-  resolved "https://registry.yarnpkg.com/ws/-/ws-7.5.3.tgz#160835b63c7d97bfab418fc1b8a9fced2ac01a74"
-  integrity sha512-kQ/dHIzuLrS6Je9+uv81ueZomEwH0qVYstcAQ4/Z93K8zeko9gtAbttJWzoC5ukqXY1PpoouV3+VSOqEAFt5wg==
-
 ws@~7.4.2:
   version "7.4.6"
   resolved "https://registry.yarnpkg.com/ws/-/ws-7.4.6.tgz#5654ca8ecdeee47c33a9a4bf6d28e2be2980377c"