diff --git a/app/src/main/java/com/github/gotify/login/LoginActivity.java b/app/src/main/java/com/github/gotify/login/LoginActivity.java
new file mode 100644
index 0000000..469581a
--- /dev/null
+++ b/app/src/main/java/com/github/gotify/login/LoginActivity.java
@@ -0,0 +1,177 @@
+package com.github.gotify.login;
+
+import android.content.DialogInterface;
+import android.content.Intent;
+import android.os.Build;
+import android.os.Bundle;
+import android.view.View;
+import android.widget.Button;
+import android.widget.EditText;
+import android.widget.ProgressBar;
+
+import com.github.gotify.R;
+import com.github.gotify.Settings;
+import com.github.gotify.Utils;
+import com.github.gotify.api.Api;
+import com.github.gotify.api.Callback;
+import com.github.gotify.api.ClientFactory;
+import com.github.gotify.client.ApiClient;
+import com.github.gotify.client.ApiException;
+import com.github.gotify.client.api.TokenApi;
+import com.github.gotify.client.api.UserApi;
+import com.github.gotify.client.model.Client;
+import com.github.gotify.client.model.VersionInfo;
+import com.github.gotify.init.InitializationActivity;
+import com.github.gotify.log.Log;
+import com.github.gotify.log.UncaughtExceptionHandler;
+import com.squareup.okhttp.HttpUrl;
+
+import androidx.appcompat.app.AlertDialog;
+import androidx.appcompat.app.AppCompatActivity;
+import butterknife.BindView;
+import butterknife.ButterKnife;
+import butterknife.OnClick;
+import butterknife.OnTextChanged;
+
+public class LoginActivity extends AppCompatActivity {
+
+    @BindView(R.id.username)
+    EditText usernameField;
+
+    @BindView(R.id.gotify_url)
+    EditText urlField;
+
+    @BindView(R.id.password)
+    EditText passwordField;
+
+    @BindView(R.id.checkurl)
+    Button checkUrlButton;
+
+    @BindView(R.id.login)
+    Button loginButton;
+
+    @BindView(R.id.checkurl_progress)
+    ProgressBar checkUrlProgress;
+
+    @BindView(R.id.login_progress)
+    ProgressBar loginProgress;
+
+    private Settings settings;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        UncaughtExceptionHandler.registerCurrentThread();
+        setContentView(R.layout.activity_login);
+        Log.i("Entering " + getClass().getSimpleName());
+        ButterKnife.bind(this);
+        settings = new Settings(this);
+    }
+
+    @OnTextChanged(R.id.gotify_url)
+    public void onUrlChange() {
+        usernameField.setVisibility(View.INVISIBLE);
+        passwordField.setVisibility(View.INVISIBLE);
+        loginButton.setVisibility(View.INVISIBLE);
+    }
+
+    @OnClick(R.id.checkurl)
+    public void doCheckUrl() {
+        String url = urlField.getText().toString();
+        if (HttpUrl.parse(url) == null) {
+            Utils.showSnackBar(LoginActivity.this, "Invalid URL (include http:// or https://)");
+            return;
+        }
+
+        checkUrlProgress.setVisibility(View.VISIBLE);
+        checkUrlButton.setVisibility(View.INVISIBLE);
+
+        final String fixedUrl = url.endsWith("/") ? url.substring(0, url.length() - 1) : url;
+
+        Api.withLogging(ClientFactory.versionApi(fixedUrl)::getVersionAsync)
+                .handleInUIThread(this, onValidUrl(fixedUrl), onInvalidUrl(fixedUrl));
+    }
+
+    private Callback.SuccessCallback<VersionInfo> onValidUrl(String url) {
+        return (version) -> {
+            settings.url(url);
+            checkUrlProgress.setVisibility(View.INVISIBLE);
+            checkUrlButton.setVisibility(View.VISIBLE);
+            checkUrlButton.setText(getString(R.string.found_gotify_version, version.getVersion()));
+            usernameField.setVisibility(View.VISIBLE);
+            usernameField.requestFocus();
+            passwordField.setVisibility(View.VISIBLE);
+            loginButton.setVisibility(View.VISIBLE);
+        };
+    }
+
+    private Callback.ErrorCallback onInvalidUrl(String url) {
+        return (exception) -> {
+            checkUrlProgress.setVisibility(View.INVISIBLE);
+            checkUrlButton.setVisibility(View.VISIBLE);
+            Utils.showSnackBar(LoginActivity.this, versionError(url, exception));
+        };
+    }
+
+    @OnClick(R.id.login)
+    public void doLogin() {
+        String username = usernameField.getText().toString();
+        String password = passwordField.getText().toString();
+
+        loginButton.setVisibility(View.INVISIBLE);
+        loginProgress.setVisibility(View.VISIBLE);
+
+        ApiClient client = ClientFactory.basicAuth(settings.url(), username, password);
+        Api.withLogging(new UserApi(client)::currentUserAsync)
+                .handleInUIThread(this, (user) -> newClientDialog(client), this::onInvalidLogin);
+    }
+
+    private void onInvalidLogin(ApiException e) {
+        loginButton.setVisibility(View.VISIBLE);
+        loginProgress.setVisibility(View.INVISIBLE);
+        Utils.showSnackBar(this, getString(R.string.wronguserpw));
+    }
+
+    private void newClientDialog(ApiClient client) {
+        EditText clientName = new EditText(this);
+        clientName.setText(Build.MODEL);
+
+        new AlertDialog.Builder(this)
+                .setTitle(R.string.create_client_title)
+                .setMessage(R.string.create_client_message)
+                .setView(clientName)
+                .setPositiveButton(R.string.create, doCreateClient(client, clientName))
+                .setNegativeButton(R.string.cancel, this::onCancelClientDialog)
+                .show();
+    }
+
+    public DialogInterface.OnClickListener doCreateClient(ApiClient client, EditText nameProvider) {
+        return (a, b) -> {
+            Client newClient = new Client().name(nameProvider.getText().toString());
+            Api.<Client>withLogging((cb) -> new TokenApi(client).createClientAsync(newClient, cb))
+                    .handleInUIThread(this, this::onCreatedClient, this::onFailedToCreateClient);
+        };
+    }
+
+    private void onCreatedClient(Client client) {
+        settings.token(client.getToken());
+        Utils.showSnackBar(this, getString(R.string.created_client));
+        startActivity(new Intent(this, InitializationActivity.class));
+        finish();
+    }
+
+    private void onFailedToCreateClient(ApiException e) {
+        Utils.showSnackBar(this, getString(R.string.create_client_failed));
+        loginProgress.setVisibility(View.INVISIBLE);
+        loginButton.setVisibility(View.VISIBLE);
+    }
+
+    private void onCancelClientDialog(DialogInterface dialog, int which) {
+        loginProgress.setVisibility(View.INVISIBLE);
+        loginButton.setVisibility(View.VISIBLE);
+    }
+
+    private String versionError(String url, ApiException exception) {
+        return getString(R.string.version_failed, url + "/version", exception.getCode());
+    }
+}
diff --git a/app/src/main/res/layout/activity_login.xml b/app/src/main/res/layout/activity_login.xml
new file mode 100644
index 0000000..3625112
--- /dev/null
+++ b/app/src/main/res/layout/activity_login.xml
@@ -0,0 +1,145 @@
+<?xml version="1.0" encoding="utf-8"?>
+<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:fillViewport="true">
+
+    <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+        xmlns:app="http://schemas.android.com/apk/res-auto"
+        xmlns:tools="http://schemas.android.com/tools"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:background="@drawable/gradient"
+        android:orientation="vertical"
+        tools:context=".login.LoginActivity"
+        tools:layout_editor_absoluteY="25dp">
+
+        <ProgressBar
+            android:id="@+id/checkurl_progress"
+            android:layout_width="49dp"
+            android:layout_height="wrap_content"
+            android:layout_marginStart="8dp"
+            android:layout_marginEnd="8dp"
+            android:layout_weight="1"
+            android:minWidth="40dp"
+            android:minHeight="40dp"
+            android:visibility="invisible"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintHorizontal_bias="0.501"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toTopOf="@+id/checkurl" />
+
+        <ProgressBar
+            android:id="@+id/login_progress"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:minWidth="40dp"
+            android:minHeight="40dp"
+            android:visibility="invisible"
+            app:layout_constraintEnd_toEndOf="@+id/checkurl"
+            app:layout_constraintStart_toStartOf="@+id/login"
+            app:layout_constraintTop_toTopOf="@+id/login" />
+
+        <ImageView
+            android:id="@+id/gotify_logo_image"
+            android:layout_width="0dp"
+            android:layout_height="180dp"
+            android:layout_alignParentTop="true"
+            android:layout_alignParentEnd="true"
+            android:layout_alignParentRight="true"
+            android:layout_marginStart="8dp"
+            android:layout_marginTop="16dp"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toTopOf="parent"
+            app:srcCompat="@drawable/gotify"
+            android:contentDescription="@string/gotify_logo" />
+
+        <EditText
+            android:id="@+id/gotify_url"
+            android:layout_width="0dp"
+            android:layout_height="42dp"
+            android:layout_alignParentTop="true"
+            android:layout_centerHorizontal="true"
+            android:layout_marginTop="8dp"
+            android:ems="10"
+            android:hint="@string/gotify_url"
+            android:inputType="textUri"
+            android:singleLine="true"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@+id/gotify_logo_image"
+            app:layout_constraintWidth_max="280dp"
+            tools:text="Gotify URL" />
+
+        <EditText
+            android:id="@+id/username"
+            android:layout_width="0dp"
+            android:layout_height="47dp"
+            android:layout_marginStart="8dp"
+            android:layout_marginTop="8dp"
+            android:layout_marginEnd="8dp"
+            android:ems="10"
+            android:hint="@string/username"
+            android:inputType="textPersonName"
+            android:visibility="invisible"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@+id/checkurl"
+            app:layout_constraintWidth_max="280dp"
+            tools:text="Username"/>
+
+        <EditText
+            android:id="@+id/password"
+            android:layout_width="0dp"
+            android:layout_height="50dp"
+            android:layout_marginStart="8dp"
+            android:layout_marginTop="8dp"
+            android:layout_marginEnd="8dp"
+            android:ems="10"
+            android:hint="@string/password"
+            android:inputType="textPassword"
+            android:visibility="invisible"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@+id/username"
+            app:layout_constraintWidth_max="280dp"
+            tools:text="Password" />
+
+        <Button
+            android:id="@+id/login"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_marginStart="8dp"
+            android:layout_marginTop="8dp"
+            android:layout_marginEnd="8dp"
+            android:background="@color/colorPrimaryDark"
+            android:textColor="@android:color/white"
+            android:text="@string/login"
+            android:visibility="invisible"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@+id/password"
+            app:layout_constraintWidth_max="280dp" />
+
+        <Button
+            android:id="@+id/checkurl"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_marginStart="8dp"
+            android:layout_marginTop="8dp"
+            android:layout_marginEnd="8dp"
+            app:layout_constraintWidth_max="280dp"
+            android:background="@color/colorPrimaryDark"
+            android:text="@string/check_url"
+            android:textColor="@android:color/white"
+            android:visibility="visible"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@+id/gotify_url" />
+
+    </androidx.constraintlayout.widget.ConstraintLayout>
+</ScrollView>