diff --git a/src/index.ts b/src/index.ts
index 70374bd..34029c7 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,6 +1,7 @@
 import $ from 'jquery';
 import {
     tests,
+    testsObservable,
     config,
     getUserAgentInfo,
     getTest,
@@ -18,7 +19,12 @@ import { uiFactory } from './ui';
 
 initialize();
 
-const ui = uiFactory(tests, reset, getCurrentTestVariation, getUserAgentInfo);
+const ui = uiFactory(
+    testsObservable,
+    reset,
+    getCurrentTestVariation,
+    getUserAgentInfo
+);
 
 $(() => {
     if (shouldShowUI()) {
diff --git a/src/main.ts b/src/main.ts
index 2d49db9..d4fc213 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -1,6 +1,7 @@
 import _getUserAgentInfo, { UserAgentInfo } from './useragentinfo';
 import userSession, { UserSession } from './usersession';
 import { SplitTest, InternalVariation } from './splittest';
+import { BehavioralSubject } from './behavioral-subject';
 export { SplitTest } from './splittest';
 import {
     TrackingDataExtender,
@@ -21,6 +22,9 @@ export interface UserConfig {
 
 const userAgentInfo = _getUserAgentInfo();
 export const tests: SplitTest[] = [];
+export const testsObservable: BehavioralSubject<
+    SplitTest[]
+> = new BehavioralSubject(tests);
 
 export function config(userConfig: UserConfig = {}) {
     if (userConfig.cookieName) {
@@ -106,6 +110,7 @@ export function create(name: string): SplitTest {
         baseTrackingDataExtenderFactory()
     );
     tests.push(test);
+    test.changes.subscribe(() => testsObservable.next(tests));
     return test;
 }
 
diff --git a/src/splittest.ts b/src/splittest.ts
index bf523dd..0fffed9 100644
--- a/src/splittest.ts
+++ b/src/splittest.ts
@@ -1,5 +1,6 @@
 import { UserAgentInfo } from './useragentinfo';
 import userSession from './usersession';
+import { BehavioralSubject } from './behavioral-subject';
 import {
     TrackingDataExtender,
     trackingDataExtenderFactory,
@@ -31,6 +32,7 @@ export interface InternalVariation extends Variation {
 
 export class SplitTest {
     isInitialized = false;
+    changes = new BehavioralSubject(this);
 
     private condition: ConditionFunction;
     private readonly _variations: InternalVariation[] = [];
@@ -85,6 +87,7 @@ export class SplitTest {
             weight: typeof variation.weight === 'number' ? variation.weight : 1
         });
         this.normalizeVariationWeights();
+        this.changes.next(this);
         return this;
     }
 
@@ -127,6 +130,7 @@ export class SplitTest {
             this.trackViewed();
         }
         this.isInitialized = true;
+        this.changes.next(this);
         return true;
     }
 
diff --git a/src/ui.ts b/src/ui.ts
index 5105701..b1511c1 100644
--- a/src/ui.ts
+++ b/src/ui.ts
@@ -1,6 +1,7 @@
 import $ from 'jquery';
 import { InternalVariation, SplitTest } from './splittest';
 import { UserAgentInfo } from './useragentinfo';
+import { BehavioralSubject } from './behavioral-subject';
 
 declare const require: any;
 
@@ -13,7 +14,7 @@ function getVariationPercentage(variation: InternalVariation): string {
 }
 
 export const uiFactory = (
-    tests: SplitTest[],
+    tests: BehavioralSubject<SplitTest[]>,
     reset: () => void,
     getCurrentTestVariation: (testName: string) => string,
     getUserAgentInfo: () => UserAgentInfo
@@ -79,8 +80,18 @@ export const uiFactory = (
         const style = document.createElement('style');
         style.innerHTML = require('./main.css');
 
+        const testListEl = document.createElement('div');
+        testListEl.className = 'test-list';
+
+        tests.subscribe(list => {
+            while (testListEl.hasChildNodes()) {
+                testListEl.removeChild(<Node>testListEl.lastChild);
+            }
+            testListEl.innerHTML = list.map(renderTest).join('');
+        });
+
         $abTestContainer = $(`<div class="ui-container hideme"></div>`).append(
-            `<div class="test-list">${tests.map(renderTest).join('')}</div>`
+            testListEl
         );
 
         $(`<button type="button" class="reset">Reset all</button>`)
@@ -102,7 +113,7 @@ export const uiFactory = (
     function show() {
         if (isInitialized) {
             $abTestContainer.removeClass('hideme');
-        } else if (tests.length > 0) {
+        } else {
             showSplitTestUi();
         }
     }