diff --git a/lib/server.js b/lib/server.js
index b4c62196e..9624d4c6b 100644
--- a/lib/server.js
+++ b/lib/server.js
@@ -8,8 +8,10 @@ const spawn = require('child_process').spawn
 const tmp = require('tmp')
 const fs = require('fs')
 const path = require('path')
+
 const BundleUtils = require('./utils/bundle-utils')
 const NetUtils = require('./utils/net-utils')
+const JsonUtils = require('./utils/json-utils')
 const root = global || window || this
 
 const cfg = require('./config')
@@ -63,7 +65,7 @@ class Server extends KarmaEventEmitter {
 
     const config = cfg.parseConfig(cliOptions.configFile, cliOptions)
 
-    this.log.debug('Final config', JSON.stringify(config, null, 2))
+    this.log.debug('Final config', JsonUtils.stringify(config, null, 2))
 
     let modules = [{
       helper: ['value', helper],
diff --git a/lib/utils/json-utils.js b/lib/utils/json-utils.js
new file mode 100644
index 000000000..a6bb481a9
--- /dev/null
+++ b/lib/utils/json-utils.js
@@ -0,0 +1,10 @@
+
+const {stringify} = require('flatted/cjs')
+
+const JsonUtils = {
+  stringify (obj) {
+    return stringify(obj)
+  }
+}
+
+module.exports = JsonUtils
diff --git a/package.json b/package.json
index 6a8005a4c..ad743dc73 100644
--- a/package.json
+++ b/package.json
@@ -412,6 +412,7 @@
     "eslint-plugin-promise": "^3.4.2",
     "eslint-plugin-react": "^7.0.1",
     "eslint-plugin-standard": "^3.0.1",
+    "flatted": "^2.0.0",
     "grunt": "^1.0.0",
     "grunt-auto-release": "^0.0.7",
     "grunt-browserify": "^5.0.0",
@@ -428,7 +429,6 @@
     "http2": "^3.3.6",
     "husky": "^0.14.3",
     "jasmine-core": "^2.3.4",
-    "json3": "^3.3.2",
     "karma-browserify": "^5.0.1",
     "karma-browserstack-launcher": "^1.0.0",
     "karma-chai": "^0.1.0",
diff --git a/test/client/karma.spec.js b/test/client/karma.spec.js
index bb933c0f6..78745962f 100644
--- a/test/client/karma.spec.js
+++ b/test/client/karma.spec.js
@@ -1,6 +1,5 @@
 // shim all the things
 require('core-js/es5')
-global.JSON = require('json3')
 var sinon = require('sinon')
 var assert = require('assert')
 
diff --git a/test/unit/utils/json-utils.spec.js b/test/unit/utils/json-utils.spec.js
new file mode 100644
index 000000000..aa6757e81
--- /dev/null
+++ b/test/unit/utils/json-utils.spec.js
@@ -0,0 +1,18 @@
+'use strict'
+
+const JsonUtils = require('../../../lib/utils/json-utils')
+
+describe('json-utils', () => {
+  it('stringify-s', () => {
+    const obj = {a: 'a', i: 1}
+    const json = JsonUtils.stringify(obj)
+    expect(json).to.be.equal('[{"a":"1","i":1},"a"]')
+  })
+  it('stringify-s circular data', () => {
+    const a = [{}]
+    a[0].a = a
+    a.push(a)
+
+    expect(JsonUtils.stringify(a)).to.be.equal('[["1","0"],{"a":"0"}]')
+  })
+})