diff --git a/README.rst b/README.rst
index d346e5a..adbcc6c 100644
--- a/README.rst
+++ b/README.rst
@@ -61,6 +61,18 @@ Afterwards you can open "kube-ops-view" via the kubectl proxy:
 Now direct your browser to http://localhost:8001/api/v1/proxy/namespaces/default/services/kube-ops-view/
 
 
+Mock Mode
+=========
+
+You can start the app in "mock mode" to see all UI features without running any Kubernetes cluster:
+
+.. code-block:: bash
+
+    $ pip3 install -r requirements.txt
+    $ (cd app && npm start &)
+    $ MOCK=true ./app.py
+
+
 Configuration
 =============
 
@@ -71,7 +83,9 @@ The following environment variables are supported:
 ``CREDENTIALS_DIR``
     Directory to read (OAuth) credentials from --- these credentials are only used for non-localhost cluster URLs.
 ``DEBUG``
-    Set to a non-empty value for local development to reload code changes.
+    Set to "true" for local development to reload code changes.
+``MOCK``
+    Set to "true" to mock Kubernetes cluster data.
 
 
 Supported Browsers
diff --git a/app.py b/app.py
index beec72b..58c732f 100755
--- a/app.py
+++ b/app.py
@@ -22,9 +22,10 @@ DEFAULT_CLUSTERS = 'http://localhost:8001/'
 CREDENTIALS_DIR = os.getenv('CREDENTIALS_DIR', '')
 AUTHORIZE_URL = os.getenv('AUTHORIZE_URL')
 APP_URL = os.getenv('APP_URL')
+MOCK = os.getenv('MOCK', '').lower() == 'true'
 
 app = Flask(__name__)
-app.debug = os.getenv('DEBUG') == 'true'
+app.debug = os.getenv('DEBUG', '').lower() == 'true'
 app.secret_key = os.getenv('SECRET_KEY', 'development')
 
 oauth = OAuth(app)
@@ -98,9 +99,49 @@ def index():
     return flask.render_template('index.html', app_js=app_js)
 
 
-@app.route('/kubernetes-clusters')
-@authorize
-def get_clusters():
+def hash_int(x: int):
+    x = ((x >> 16) ^ x) * 0x45d9f3b
+    x = ((x >> 16) ^ x) * 0x45d9f3b
+    x = (x >> 16) ^ x
+    return x
+
+
+def generate_mock_cluster_data(index: int):
+    '''Generate deterministic (no randomness!) mock data'''
+    nodes = []
+    pod_phases = ['Pending', 'Running', 'Running']
+    for i in range(10):
+        labels = {}
+        if i < 2:
+            labels['master'] = 'true'
+        pods = []
+        for j in range(hash_int((index + 1) * (i + 1)) % 32):
+            phase = pod_phases[hash_int((index + 1) * (i + 1) * (j + 1)) % len(pod_phases)]
+            containers = []
+            for k in range(1):
+                containers.append({'name': 'myapp', 'image': 'foo/bar/{}'.format(j), 'resources': {'requests': {'cpu': '100m', 'memory': '100Mi'}}})
+            status = {'phase': phase}
+            if phase == 'Running':
+                if j % 10 == 0:
+                    status['containerStatuses'] = [{'ready': False, 'state': {'waiting': {'reason': 'CrashLoopBackOff'}}}]
+            pods.append({'name': 'my-pod-{}'.format(j), 'namespace': 'kube-system' if j < 3 else 'default', 'labels': labels, 'status': status, 'containers': containers})
+        nodes.append({'name': 'node-{}'.format(i), 'labels': labels, 'status': {'capacity': {'cpu': '4', 'memory': '32Gi', 'pods': '110'}}, 'pods': pods})
+    unassigned_pods = []
+    return {
+        'api_server_url': 'https://kube-{}.example.org'.format(index),
+        'nodes': nodes,
+        'unassigned_pods': unassigned_pods
+    }
+
+
+def get_mock_clusters():
+    clusters = []
+    for i in range(3):
+        clusters.append(generate_mock_cluster_data(i))
+    return clusters
+
+
+def get_kubernetes_clusters():
     clusters = []
     for api_server_url in (os.getenv('CLUSTERS') or DEFAULT_CLUSTERS).split(','):
         if 'localhost' not in api_server_url:
@@ -152,6 +193,16 @@ def get_clusters():
         except:
             logging.exception('Failed to get metrics')
         clusters.append({'api_server_url': api_server_url, 'nodes': nodes, 'unassigned_pods': unassigned_pods})
+    return clusters
+
+
+@app.route('/kubernetes-clusters')
+@authorize
+def get_clusters():
+    if MOCK:
+        clusters = get_mock_clusters()
+    else:
+        clusters = get_kubernetes_clusters()
 
     return json.dumps({'kubernetes_clusters': clusters}, separators=(',', ':'))
 
diff --git a/app/src/app.js b/app/src/app.js
index f5f4c66..15ea16e 100644
--- a/app/src/app.js
+++ b/app/src/app.js
@@ -101,7 +101,7 @@ export default class App {
     }
 
     animatePodCreation(originalPod, globalX, globalY) {
-        const pod = new Pod(originalPod.pod, this.tooltip, false)
+        const pod = new Pod(originalPod.pod, this.tooltip, null)
         pod.draw()
         const targetPosition = new PIXI.Point(globalX, globalY)
         const angle = Math.random()*Math.PI*2
diff --git a/app/src/cluster.js b/app/src/cluster.js
index 3c290ca..b6eb3a2 100644
--- a/app/src/cluster.js
+++ b/app/src/cluster.js
@@ -13,7 +13,7 @@ export default class Cluster extends PIXI.Graphics {
     draw () {
         var rows = [10, 10]
         for (var node of this.cluster.nodes) {
-            var nodeBox = new Node(node, this.tooltip)
+            var nodeBox = new Node(node, this, this.tooltip)
             nodeBox.draw()
             if (nodeBox.isMaster()) {
                 nodeBox.x = rows[0]
@@ -30,7 +30,7 @@ export default class Cluster extends PIXI.Graphics {
 
 
         for (const pod of this.cluster.unassigned_pods) {
-            var podBox = Pod.getOrCreate(pod, this.tooltip)
+            var podBox = Pod.getOrCreate(pod, this, this.tooltip)
             podBox.x = rows[0]
             podBox.y = 20
             podBox.draw()
diff --git a/app/src/node.js b/app/src/node.js
index f166812..03572ac 100644
--- a/app/src/node.js
+++ b/app/src/node.js
@@ -4,9 +4,10 @@ import {parseResource} from './utils.js'
 const PIXI = require('pixi.js')
 
 export default class Node extends PIXI.Graphics {
-    constructor(node, tooltip) {
+    constructor(node, cluster, tooltip) {
         super()
         this.node = node
+        this.cluster = cluster
         this.tooltip = tooltip
     }
 
@@ -82,7 +83,7 @@ export default class Node extends PIXI.Graphics {
         var py = 20
         for (const pod of this.node.pods) {
             if (pod.namespace != 'kube-system') {
-                const podBox = Pod.getOrCreate(pod, this.tooltip) //new Pod(pod, this.tooltip)
+                const podBox = Pod.getOrCreate(pod, this.cluster, this.tooltip) //new Pod(pod, this.tooltip)
                 podBox.x = px
                 podBox.y = py
                 nodeBox.addChild(podBox.draw())
@@ -98,7 +99,7 @@ export default class Node extends PIXI.Graphics {
         py = 100
         for (const pod of this.node.pods) {
             if (pod.namespace == 'kube-system') {
-                const podBox = Pod.getOrCreate(pod, this.tooltip) //new Pod(pod, this.tooltip)
+                const podBox = Pod.getOrCreate(pod, this.cluster, this.tooltip) //new Pod(pod, this.tooltip)
                 podBox.x = px
                 podBox.y = py
                 nodeBox.addChild(podBox.draw())
diff --git a/app/src/pod.js b/app/src/pod.js
index 23b9948..e60eae4 100644
--- a/app/src/pod.js
+++ b/app/src/pod.js
@@ -5,15 +5,15 @@ export const ALL_PODS = {}
 
 export class Pod extends PIXI.Graphics {
 
-    constructor(pod, tooltip, register=true) {
+    constructor(pod, tooltip, cluster) {
         super()
         this.pod = pod
         this.tooltip = tooltip
         this.tick = null
         this._progress = 1
 
-        if (register) {
-            ALL_PODS[pod.namespace + '/' + pod.name] = this
+        if (cluster) {
+            ALL_PODS[cluster.cluster.api_server_url + '/' + pod.namespace + '/' + pod.name] = this
         }
     }
 
@@ -51,8 +51,8 @@ export class Pod extends PIXI.Graphics {
         }
     }
 
-    static getOrCreate(pod, tooltip) {
-        const existingPod = ALL_PODS[pod.namespace + '/' + pod.name]
+    static getOrCreate(pod, cluster, tooltip) {
+        const existingPod = ALL_PODS[cluster.cluster.api_server_url + '/' + pod.namespace + '/' + pod.name]
         if (existingPod) {
             existingPod.pod = pod
             existingPod.clear()
diff --git a/tox.ini b/tox.ini
new file mode 100644
index 0000000..2eab242
--- /dev/null
+++ b/tox.ini
@@ -0,0 +1,3 @@
+[flake8]
+max-line-length=120
+ignore=E402