diff --git a/src/routes/domains.js b/src/routes/domains.js
index 48b4ba281..02401dd09 100644
--- a/src/routes/domains.js
+++ b/src/routes/domains.js
@@ -25,7 +25,7 @@ function add(req, res, next) {
     if (req.body.fallbackCertificate && (!req.body.key || typeof req.body.key !== 'string')) return next(new HttpError(400, 'fallbackCertificate.key must be a string'));
 
     domains.add(req.body.domain, req.body.zoneName || req.body.domain, req.body.config, req.body.fallbackCertificate || null, function (error) {
-        if (error && error.reason === DomainError.ALREADY_EXISTS) return next(new HttpError(400, error.message));
+        if (error && error.reason === DomainError.ALREADY_EXISTS) return next(new HttpError(409, error.message));
         if (error && error.reason === DomainError.BAD_FIELD) return next(new HttpError(400, error.message));
         if (error && error.reason === DomainError.INVALID_PROVIDER) return next(new HttpError(400, error.message));
         if (error) return next(new HttpError(500, error));
diff --git a/src/routes/test/domains-test.js b/src/routes/test/domains-test.js
new file mode 100644
index 000000000..67d5ed0ad
--- /dev/null
+++ b/src/routes/test/domains-test.js
@@ -0,0 +1,240 @@
+'use strict';
+
+/* global it:false */
+/* global describe:false */
+/* global before:false */
+/* global after:false */
+
+var async = require('async'),
+    config = require('../../config.js'),
+    database = require('../../database.js'),
+    expect = require('expect.js'),
+    nock = require('nock'),
+    superagent = require('superagent'),
+    server = require('../../server.js');
+
+var SERVER_URL = 'http://localhost:' + config.get('port');
+
+var USERNAME = 'superadmin', PASSWORD = 'Foobar?1337', EMAIL ='silly@me.com';
+var token = null;
+
+var DOMAIN_0 = {
+    domain: 'cloudron.com',
+    zoneName: 'cloudron.com',
+    config: { provider: 'noop' }
+};
+
+var DOMAIN_1 = {
+    domain: 'foobar.com',
+    config: { provider: 'noop' }
+};
+
+describe('Domains API', function () {
+    this.timeout(10000);
+
+    before(function (done) {
+        // we test digitalocean here
+        config.set('provider', 'digitalocean');
+        config.set('fqdn', 'example.com');
+
+        async.series([
+            server.start.bind(null),
+            database._clear.bind(null),
+
+            function (callback) {
+                superagent.post(SERVER_URL + '/api/v1/cloudron/activate')
+                        .query({ setupToken: 'somesetuptoken' })
+                        .send({ username: USERNAME, password: PASSWORD, email: EMAIL })
+                        .end(function (error, result) {
+                    expect(result).to.be.ok();
+                    expect(result.statusCode).to.equal(201);
+
+                    // stash token for further use
+                    token = result.body.token;
+
+                    callback();
+                });
+            },
+        ], done);
+    });
+
+    after(function (done) {
+        async.series([
+            database._clear.bind(null),
+            server.stop.bind(null)
+        ], done);
+    });
+
+    describe('add', function () {
+        it('fails with missing domain', function (done) {
+            superagent.post(SERVER_URL + '/api/v1/domains')
+                    .query({ access_token: token })
+                    .send({})
+                    .end(function (error, result) {
+                expect(result.statusCode).to.equal(400);
+
+                done();
+            });
+        });
+
+        it('fails with invalid domain', function (done) {
+            superagent.post(SERVER_URL + '/api/v1/domains')
+                    .query({ access_token: token })
+                    .send({ domain: 'abc' })
+                    .end(function (error, result) {
+                expect(result.statusCode).to.equal(400);
+
+                done();
+            });
+        });
+
+        it('fails with unknown provider', function (done) {
+            var scope = nock(config.apiServerOrigin()).get('/api/v1/helper/public_ip').reply(200, { ip: '127.0.0.1' });
+
+            superagent.post(SERVER_URL + '/api/v1/domains')
+                    .query({ access_token: token })
+                    .send({ domain: 'cloudron.com', config: { provider: 'doesnotexist' }})
+                    .end(function (error, result) {
+                expect(result.statusCode).to.equal(400);
+                expect(scope.isDone()).to.be.ok();
+
+                done();
+            });
+        });
+
+        it('succeeds', function (done) {
+            var scope = nock(config.apiServerOrigin()).get('/api/v1/helper/public_ip').reply(200, { ip: '127.0.0.1' });
+
+            superagent.post(SERVER_URL + '/api/v1/domains')
+                    .query({ access_token: token })
+                    .send(DOMAIN_0)
+                    .end(function (error, result) {
+                expect(result.statusCode).to.equal(201);
+                expect(scope.isDone()).to.be.ok();
+
+                done();
+            });
+        });
+
+        it('succeeds for second domain without zoneName', function (done) {
+            var scope = nock(config.apiServerOrigin()).get('/api/v1/helper/public_ip').reply(200, { ip: '127.0.0.1' });
+
+            superagent.post(SERVER_URL + '/api/v1/domains')
+                    .query({ access_token: token })
+                    .send(DOMAIN_1)
+                    .end(function (error, result) {
+                expect(result.statusCode).to.equal(201);
+                expect(scope.isDone()).to.be.ok();
+
+                done();
+            });
+        });
+
+        it('fails for already added domain', function (done) {
+            var scope = nock(config.apiServerOrigin()).get('/api/v1/helper/public_ip').reply(200, { ip: '127.0.0.1' });
+
+            superagent.post(SERVER_URL + '/api/v1/domains')
+                    .query({ access_token: token })
+                    .send(DOMAIN_0)
+                    .end(function (error, result) {
+                expect(result.statusCode).to.equal(409);
+                expect(scope.isDone()).to.be.ok();
+
+                done();
+            });
+        });
+    });
+
+    describe('list', function () {
+        it('succeeds', function (done) {
+            superagent.get(SERVER_URL + '/api/v1/domains')
+                    .query({ access_token: token })
+                    .end(function (error, result) {
+                expect(result.statusCode).to.equal(200);
+                expect(result.body.domains).to.be.an(Array);
+                // includes currently the implicitly added config.fqdn()
+                expect(result.body.domains.length).to.equal(3);
+
+                expect(result.body.domains[0].domain).to.equal(DOMAIN_0.domain);
+                expect(result.body.domains[1].domain).to.equal(config.fqdn());
+                expect(result.body.domains[2].domain).to.equal(DOMAIN_1.domain);
+
+                done();
+            });
+        });
+    });
+
+    describe('get', function () {
+        it('fails for non-existing domain', function (done) {
+            superagent.get(SERVER_URL + '/api/v1/domains/' + DOMAIN_0.domain + DOMAIN_0.domain)
+                    .query({ access_token: token })
+                    .end(function (error, result) {
+                expect(result.statusCode).to.equal(404);
+
+                done();
+            });
+        });
+
+        it('succeeds', function (done) {
+            superagent.get(SERVER_URL + '/api/v1/domains/' + DOMAIN_0.domain)
+                    .query({ access_token: token })
+                    .end(function (error, result) {
+                expect(result.statusCode).to.equal(200);
+                expect(result.body.domain).to.equal(DOMAIN_0.domain);
+
+                done();
+            });
+        });
+    });
+
+    describe('delete', function () {
+        it('fails without password', function (done) {
+            superagent.delete(SERVER_URL + '/api/v1/domains/' + DOMAIN_0.domain + DOMAIN_0.domain)
+                    .query({ access_token: token })
+                    .end(function (error, result) {
+                expect(result.statusCode).to.equal(400);
+
+                done();
+            });
+        });
+
+        it('fails with wrong password', function (done) {
+            superagent.delete(SERVER_URL + '/api/v1/domains/' + DOMAIN_0.domain + DOMAIN_0.domain)
+                    .query({ access_token: token })
+                    .send({ password: PASSWORD + PASSWORD })
+                    .end(function (error, result) {
+                expect(result.statusCode).to.equal(403);
+
+                done();
+            });
+        });
+
+        it('fails for non-existing domain', function (done) {
+            superagent.delete(SERVER_URL + '/api/v1/domains/' + DOMAIN_0.domain + DOMAIN_0.domain)
+                    .query({ access_token: token })
+                    .send({ password: PASSWORD })
+                    .end(function (error, result) {
+                expect(result.statusCode).to.equal(404);
+
+                done();
+            });
+        });
+
+        it('succeeds', function (done) {
+            superagent.delete(SERVER_URL + '/api/v1/domains/' + DOMAIN_0.domain)
+                    .query({ access_token: token })
+                    .send({ password: PASSWORD })
+                    .end(function (error, result) {
+                expect(result.statusCode).to.equal(204);
+
+                superagent.get(SERVER_URL + '/api/v1/domains/' + DOMAIN_0.domain)
+                        .query({ access_token: token })
+                        .end(function (error, result) {
+                    expect(result.statusCode).to.equal(404);
+
+                    done();
+                });
+            });
+        });
+    });
+});