diff --git a/app/Models/Configuration.php b/app/Models/Configuration.php
index 3a0617d92f..8f29c16dc0 100644
--- a/app/Models/Configuration.php
+++ b/app/Models/Configuration.php
@@ -29,6 +29,7 @@ use Illuminate\Database\Eloquent\SoftDeletes;
  * Class Configuration.
  *
  * @property string $data
+ * @property string $name
  */
 class Configuration extends Model
 {
diff --git a/routes/api.php b/routes/api.php
index 8083a43212..37a33015f7 100644
--- a/routes/api.php
+++ b/routes/api.php
@@ -130,7 +130,7 @@ Route::group(
 
         // Configuration API routes:
         Route::get('', ['uses' => 'ConfigurationController@index', 'as' => 'index']);
-        Route::put('', ['uses' => 'ConfigurationController@update', 'as' => 'update']);
+        Route::post('', ['uses' => 'ConfigurationController@update', 'as' => 'update']);
     }
 );
 
diff --git a/tests/Api/V1/Controllers/BudgetLimitControllerTest.php b/tests/Api/V1/Controllers/BudgetLimitControllerTest.php
index 1af35c2f91..47a222a80f 100644
--- a/tests/Api/V1/Controllers/BudgetLimitControllerTest.php
+++ b/tests/Api/V1/Controllers/BudgetLimitControllerTest.php
@@ -249,6 +249,7 @@ class BudgetLimitControllerTest extends TestCase
         // call API
         $response = $this->post('/api/v1/budget_limits', $data);
         $response->assertStatus(500);
+        $response->assertSee('Unknown budget.');
     }
 
     /**
@@ -324,6 +325,7 @@ class BudgetLimitControllerTest extends TestCase
         // call API
         $response = $this->put('/api/v1/budget_limits/' . $budgetLimit->id, $data);
         $response->assertStatus(500);
+        $response->assertSee('Unknown budget.');
     }
 
 }
\ No newline at end of file
diff --git a/tests/Api/V1/Controllers/CategoryControllerTest.php b/tests/Api/V1/Controllers/CategoryControllerTest.php
new file mode 100644
index 0000000000..4782bac76c
--- /dev/null
+++ b/tests/Api/V1/Controllers/CategoryControllerTest.php
@@ -0,0 +1,175 @@
+<?php
+/**
+ * CategoryControllerTest.php
+ * Copyright (c) 2018 thegrumpydictator@gmail.com
+ *
+ * This file is part of Firefly III.
+ *
+ * Firefly III is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Firefly III is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Firefly III. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+declare(strict_types=1);
+
+namespace Tests\Api\V1\Controllers;
+
+
+use FireflyIII\Models\Budget;
+use FireflyIII\Repositories\Category\CategoryRepositoryInterface;
+use Laravel\Passport\Passport;
+use Log;
+use Tests\TestCase;
+
+/**
+ *
+ * Class CategoryControllerTest
+ */
+class CategoryControllerTest extends TestCase
+{
+    /**
+     *
+     */
+    public function setUp(): void
+    {
+        parent::setUp();
+        Passport::actingAs($this->user());
+        Log::debug(sprintf('Now in %s.', \get_class($this)));
+    }
+
+    /**
+     * Delete a category.
+     *
+     * @covers \FireflyIII\Api\V1\Controllers\CategoryController
+     */
+    public function testDelete(): void
+    {
+        // mock stuff:
+        $repository = $this->mock(CategoryRepositoryInterface::class);
+
+        // mock calls:
+        $repository->shouldReceive('setUser')->once();
+        $repository->shouldReceive('destroy')->once()->andReturn(true);
+
+        // get category:
+        $category = $this->user()->categories()->first();
+
+        // call API
+        $response = $this->delete('/api/v1/categories/' . $category->id);
+        $response->assertStatus(204);
+    }
+
+    /**
+     * Show all categories
+     *
+     * @covers \FireflyIII\Api\V1\Controllers\CategoryController
+     */
+    public function testIndex(): void
+    {
+        $categories = $this->user()->categories()->get();
+        // mock stuff:
+        $repository = $this->mock(CategoryRepositoryInterface::class);
+
+        // mock calls:
+        $repository->shouldReceive('setUser')->once();
+        $repository->shouldReceive('getCategories')->once()->andReturn($categories);
+
+        // call API
+        $response = $this->get('/api/v1/categories');
+        $response->assertStatus(200);
+        $response->assertSee($categories->first()->name);
+    }
+
+    /**
+     * Show a single category.
+     *
+     * @covers \FireflyIII\Api\V1\Controllers\CategoryController
+     */
+    public function testShow(): void
+    {
+        $category = $this->user()->categories()->first();
+        // mock stuff:
+        $repository = $this->mock(CategoryRepositoryInterface::class);
+
+        // mock calls:
+        $repository->shouldReceive('setUser')->once();
+
+        // call API
+        $response = $this->get('/api/v1/categories/' . $category->id);
+        $response->assertStatus(200);
+        $response->assertSee($category->name);
+    }
+
+    /**
+     * Store a new category.
+     *
+     * @covers \FireflyIII\Api\V1\Controllers\CategoryController
+     */
+    public function testStore(): void
+    {
+        /** @var Budget $category */
+        $category = $this->user()->categories()->first();
+
+        // mock stuff:
+        $repository = $this->mock(CategoryRepositoryInterface::class);
+
+        // mock calls:
+        $repository->shouldReceive('setUser')->once();
+        $repository->shouldReceive('store')->once()->andReturn($category);
+
+        // data to submit
+        $data = [
+            'name'   => 'Some category',
+            'active' => '1',
+        ];
+
+        // test API
+        $response = $this->post('/api/v1/categories', $data);
+        $response->assertStatus(200);
+        $response->assertJson(['data' => ['type' => 'categories', 'links' => true],]);
+        $response->assertSee($category->name); // the amount
+        $response->assertHeader('Content-Type', 'application/vnd.api+json');
+    }
+
+    /**
+     * Update a category.
+     *
+     * @covers \FireflyIII\Api\V1\Controllers\CategoryController
+     */
+    public function testUpdate(): void
+    {
+        // mock repositories
+        $repository = $this->mock(CategoryRepositoryInterface::class);
+
+        /** @var Budget $category */
+        $category = $this->user()->categories()->first();
+
+        // mock calls:
+        $repository->shouldReceive('setUser');
+        $repository->shouldReceive('update')->once()->andReturn($category);
+
+        // data to submit
+        $data = [
+            'name'   => 'Some new category',
+            'active' => '1',
+        ];
+
+        // test API
+        $response = $this->put('/api/v1/categories/' . $category->id, $data, ['Accept' => 'application/json']);
+        $response->assertStatus(200);
+        $response->assertJson(['data' => ['type' => 'categories', 'links' => true],]);
+        $response->assertHeader('Content-Type', 'application/vnd.api+json');
+        $response->assertSee($category->name);
+    }
+
+
+}
\ No newline at end of file
diff --git a/tests/Api/V1/Controllers/ConfigurationControllerTest.php b/tests/Api/V1/Controllers/ConfigurationControllerTest.php
new file mode 100644
index 0000000000..ab958a1f2f
--- /dev/null
+++ b/tests/Api/V1/Controllers/ConfigurationControllerTest.php
@@ -0,0 +1,185 @@
+<?php
+/**
+ * ConfigurationControllerTest.php
+ * Copyright (c) 2018 thegrumpydictator@gmail.com
+ *
+ * This file is part of Firefly III.
+ *
+ * Firefly III is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Firefly III is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Firefly III. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+declare(strict_types=1);
+
+namespace Tests\Api\V1\Controllers;
+
+use FireflyConfig;
+use FireflyIII\Models\Configuration;
+use Laravel\Passport\Passport;
+use Log;
+use Tests\TestCase;
+
+/**
+ *
+ * Class ConfigurationControllerTest
+ */
+class ConfigurationControllerTest extends TestCase
+{
+    /**
+     *
+     */
+    public function setUp(): void
+    {
+        parent::setUp();
+        Passport::actingAs($this->user());
+        Log::debug(sprintf('Now in %s.', \get_class($this)));
+    }
+
+    /**
+     * Get configuration variables.
+     *
+     * @covers \FireflyIII\Api\V1\Controllers\ConfigurationController
+     */
+    public function testIndex(): void
+    {
+        $demoConfig       = new Configuration;
+        $demoConfig->name = 'is_demo_site';
+        $demoConfig->data = false;
+
+        $permConfig       = new Configuration;
+        $permConfig->name = 'permission_update_check';
+        $permConfig->data = -1;
+
+        $lastConfig       = new Configuration;
+        $lastConfig->name = 'last_update_check';
+        $lastConfig->data = 123456789;
+
+        $singleConfig       = new Configuration;
+        $singleConfig->name = 'single_user_mode';
+        $singleConfig->data = true;
+
+        FireflyConfig::shouldReceive('get')->withArgs(['is_demo_site'])->andReturn($demoConfig)->once();
+        FireflyConfig::shouldReceive('get')->withArgs(['permission_update_check'])->andReturn($permConfig)->once();
+        FireflyConfig::shouldReceive('get')->withArgs(['last_update_check'])->andReturn($lastConfig)->once();
+        FireflyConfig::shouldReceive('get')->withArgs(['single_user_mode'])->andReturn($singleConfig)->once();
+
+        $expected = [
+            'data' => [
+                'is_demo_site'            => false,
+                'permission_update_check' => -1,
+                'last_update_check'       => 123456789,
+                'single_user_mode'        => true,
+            ],
+        ];
+
+        $response = $this->get('/api/v1/configuration');
+        $response->assertStatus(200);
+        $response->assertExactJson($expected);
+        $response->assertHeader('Content-Type', 'application/vnd.api+json');
+    }
+
+
+    /**
+     * Get configuration variables.
+     *
+     * @covers \FireflyIII\Api\V1\Controllers\ConfigurationController
+     */
+    public function testIndexNotOwner(): void
+    {
+        Passport::actingAs($this->emptyUser());
+        $response = $this->get('/api/v1/configuration');
+        $response->assertStatus(500);
+        $response->assertSee('No access to method.');
+    }
+
+    /**
+     * Set configuration variables.
+     *
+     * @covers \FireflyIII\Api\V1\Controllers\ConfigurationController
+     */
+    public function testUpdate(): void
+    {
+        $data     = [
+            'name'  => 'permission_update_check',
+            'value' => 1,
+
+        ];
+
+        $demoConfig       = new Configuration;
+        $demoConfig->name = 'is_demo_site';
+        $demoConfig->data = false;
+
+        $permConfig       = new Configuration;
+        $permConfig->name = 'permission_update_check';
+        $permConfig->data = -1;
+
+        $lastConfig       = new Configuration;
+        $lastConfig->name = 'last_update_check';
+        $lastConfig->data = 123456789;
+
+        $singleConfig       = new Configuration;
+        $singleConfig->name = 'single_user_mode';
+        $singleConfig->data = true;
+
+        FireflyConfig::shouldReceive('get')->withArgs(['is_demo_site'])->andReturn($demoConfig)->once();
+        FireflyConfig::shouldReceive('get')->withArgs(['permission_update_check'])->andReturn($permConfig)->once();
+        FireflyConfig::shouldReceive('get')->withArgs(['last_update_check'])->andReturn($lastConfig)->once();
+        FireflyConfig::shouldReceive('get')->withArgs(['single_user_mode'])->andReturn($singleConfig)->once();
+        FireflyConfig::shouldReceive('set')->once()->withArgs(['permission_update_check',1]);
+
+
+        $expected = [
+            'data' => [
+                'is_demo_site'            => false,
+                'permission_update_check' => -1,
+                'last_update_check'       => 123456789,
+                'single_user_mode'        => true,
+            ],
+        ];
+
+        $response = $this->post('/api/v1/configuration', $data);
+        $response->assertStatus(200);
+        $response->assertExactJson($expected);
+    }
+
+    /**
+     * Set configuration variable that you're not allowed to change
+     *
+     * @covers \FireflyIII\Api\V1\Controllers\ConfigurationController
+     */
+    public function testUpdateInvalid(): void
+    {
+        $data     = [
+            'name'  => 'last_update_check',
+            'value' => 'true',
+        ];
+        $response = $this->post('/api/v1/configuration', $data);
+        $response->assertStatus(500);
+        $response->assertSee('You cannot edit this configuration value.');
+    }
+
+    /**
+     * Set configuration variables but you're  not the owner.
+     *
+     * @covers \FireflyIII\Api\V1\Controllers\ConfigurationController
+     */
+    public function testUpdateNotOwner(): void
+    {
+        Passport::actingAs($this->emptyUser());
+        $response = $this->post('/api/v1/configuration');
+        $response->assertStatus(500);
+        $response->assertSee('No access to method.');
+    }
+
+
+}
\ No newline at end of file