diff --git a/lib/web/websocket/permessage-deflate.js b/lib/web/websocket/permessage-deflate.js
new file mode 100644
index 00000000000..6b808e7239e
--- /dev/null
+++ b/lib/web/websocket/permessage-deflate.js
@@ -0,0 +1,39 @@
+'use strict'
+
+const { createInflateRaw } = require('node:zlib')
+
+const tail = Buffer.from([0x00, 0x00, 0xff, 0xff])
+const kBuffer = Symbol('kBuffer')
+
+class PerMessageDeflate {
+  /** @type {import('node:zlib').InflateRaw} */
+  #inflate
+
+  decompress (chunk, fin, callback) {
+    // An endpoint uses the following algorithm to decompress a message.
+    // 1.  Append 4 octets of 0x00 0x00 0xff 0xff to the tail end of the
+    //     payload of the message.
+    // 2.  Decompress the resulting data using DEFLATE.
+
+    if (!this.#inflate) {
+      this.#inflate = createInflateRaw(/* TODO */)
+      this.#inflate[kBuffer] = []
+
+      this.#inflate.on('data', (data) => this.#inflate[kBuffer].push(data))
+    }
+
+    this.#inflate.write(chunk)
+    if (fin) {
+      this.#inflate.write(tail)
+    }
+
+    this.#inflate.flush(() => {
+      const full = Buffer.concat(this.#inflate[kBuffer])
+      callback(full)
+
+      this.#inflate[kBuffer].length = 0
+    })
+  }
+}
+
+module.exports = { PerMessageDeflate }
diff --git a/lib/web/websocket/receiver.js b/lib/web/websocket/receiver.js
index 748d14123c5..ea94bd50b53 100644
--- a/lib/web/websocket/receiver.js
+++ b/lib/web/websocket/receiver.js
@@ -17,6 +17,7 @@ const {
 } = require('./util')
 const { WebsocketFrameSend } = require('./frame')
 const { closeWebSocketConnection } = require('./connection')
+const { PerMessageDeflate } = require('./permessage-deflate')
 
 // This code was influenced by ws released under the MIT license.
 // Copyright (c) 2011 Einar Otto Stangvik <einaros@gmail.com>
@@ -33,14 +34,18 @@ class ByteParser extends Writable {
   #info = {}
   #fragments = []
 
-  /** @type {Set<string>} */
+  /** @type {Map<string, PerMessageDeflate>} */
   #extensions
 
   constructor (ws, extensions) {
     super()
 
     this.ws = ws
-    this.#extensions = new Set(extensions)
+    this.#extensions = extensions == null ? new Map() : extensions
+
+    if (this.#extensions.has('permessage-deflate')) {
+      this.#extensions.set('permessage-deflate', new PerMessageDeflate())
+    }
   }
 
   /**
@@ -157,6 +162,7 @@ class ByteParser extends Writable {
         this.#info.masked = masked
         this.#info.fin = fin
         this.#info.fragmented = fragmented
+        this.#info.compressed = rsv1 !== 0
       } else if (this.#state === parserStates.PAYLOADLENGTH_16) {
         if (this.#byteOffset < 2) {
           return callback()
@@ -199,16 +205,22 @@ class ByteParser extends Writable {
         if (isControlFrame(this.#info.opcode)) {
           this.#loop = this.parseControlFrame(body)
         } else {
-          this.#fragments.push(body)
-
-          // If the frame is not fragmented, a message has been received.
-          // If the frame is fragmented, it will terminate with a fin bit set
-          // and an opcode of 0 (continuation), therefore we handle that when
-          // parsing continuation frames, not here.
-          if (!this.#info.fragmented && this.#info.fin) {
-            const fullMessage = Buffer.concat(this.#fragments)
-            websocketMessageReceived(this.ws, this.#info.binaryType, fullMessage)
-            this.#fragments.length = 0
+          if (!this.#info.compressed) {
+            this.#fragments.push(body)
+
+            // If the frame is not fragmented, a message has been received.
+            // If the frame is fragmented, it will terminate with a fin bit set
+            // and an opcode of 0 (continuation), therefore we handle that when
+            // parsing continuation frames, not here.
+            if (!this.#info.fragmented && this.#info.fin) {
+              const fullMessage = Buffer.concat(this.#fragments)
+              websocketMessageReceived(this.ws, this.#info.binaryType, fullMessage)
+              this.#fragments.length = 0
+            }
+          } else {
+            this.#extensions.get('permessage-deflate').decompress(body, this.#info.fin, (data) => {
+              websocketMessageReceived(this.ws, this.#info.binaryType, data)
+            })
           }
         }