diff --git a/package.json b/package.json
index 12613b4..5fb3a86 100644
--- a/package.json
+++ b/package.json
@@ -29,6 +29,7 @@
   },
   "homepage": "https://github.com/diasdavid/js-libp2p-websockets#readme",
   "dependencies": {
+    "mafmt": "^1.0.1",
     "multiaddr": "^1.1.1",
     "simple-websocket": "github:diasdavid/simple-websocket#ec31437"
   },
diff --git a/src/index.js b/src/index.js
index d1f13a2..f93b17f 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,7 +1,7 @@
 // const debug = require('debug')
 // const log = debug('libp2p:tcp')
-// const multiaddr = require('multiaddr')
 const SWS = require('simple-websocket')
+const mafmt = require('mafmt')
 
 exports = module.exports = WebSockets
 
@@ -73,8 +73,7 @@ function WebSockets () {
 
   this.filter = (multiaddrs) => {
     return multiaddrs.filter((ma) => {
-      // TODO
-      // https://github.com/whyrusleeping/js-mafmt/pull/2
+      return mafmt.WebSockets.matches(ma)
     })
   }
 }
diff --git a/tests/libp2p-websockets-test.js b/tests/libp2p-websockets-test.js
index 4c34321..f75d14a 100644
--- a/tests/libp2p-websockets-test.js
+++ b/tests/libp2p-websockets-test.js
@@ -52,4 +52,15 @@ describe('libp2p-websockets', function () {
       conn.end()
     })
   })
+
+  it('filter', (done) => {
+    const mh1 = multiaddr('/ip4/127.0.0.1/tcp/9090')
+    const mh2 = multiaddr('/ip4/127.0.0.1/udp/9090')
+    const mh3 = multiaddr('/ip4/127.0.0.1/tcp/9090/websockets')
+
+    const valid = ws.filter([mh1, mh2, mh3])
+    expect(valid.length).to.equal(1)
+    expect(valid[0]).to.deep.equal(mh3)
+    done()
+  })
 })