diff --git a/src/reverseproxy.js b/src/reverseproxy.js
index 0ab403211..38a68a6a8 100644
--- a/src/reverseproxy.js
+++ b/src/reverseproxy.js
@@ -554,24 +554,24 @@ async function writeAppConfig(app) {
     assert.strictEqual(typeof app, 'object');
 
     let appDomains = [];
-    appDomains.push({ domain: app.domain, fqdn: app.fqdn, type: 'primary' });
+    appDomains.push({ domain: app.domain, fqdn: app.fqdn, type: apps.SUBDOMAIN_TYPE_PRIMARY });
 
     app.redirectDomains.forEach(function (redirectDomain) {
-        appDomains.push({ domain: redirectDomain.domain, fqdn: redirectDomain.fqdn, type: 'alternate' });
+        appDomains.push({ domain: redirectDomain.domain, fqdn: redirectDomain.fqdn, type: apps.SUBDOMAIN_TYPE_REDIRECT });
     });
 
     app.aliasDomains.forEach(function (aliasDomain) {
-        appDomains.push({ domain: aliasDomain.domain, fqdn: aliasDomain.fqdn, type: 'alias' });
+        appDomains.push({ domain: aliasDomain.domain, fqdn: aliasDomain.fqdn, type: apps.SUBDOMAIN_TYPE_ALIAS });
     });
 
     for (const appDomain of appDomains) {
         const bundle = await getCertificatePath(appDomain.fqdn, appDomain.domain);
 
-        if (appDomain.type === 'primary') {
+        if (appDomain.type === apps.SUBDOMAIN_TYPE_PRIMARY) {
             await writeAppNginxConfig(app, appDomain.fqdn, bundle);
-        } else if (appDomain.type === 'alternate') {
+        } else if (appDomain.type === apps.SUBDOMAIN_TYPE_REDIRECT) {
             await writeAppRedirectNginxConfig(app, appDomain.fqdn, bundle);
-        } else if (appDomain.type === 'alias') {
+        } else if (appDomain.type === apps.SUBDOMAIN_TYPE_ALIAS) {
             await writeAppNginxConfig(app, appDomain.fqdn, bundle);
         }
     }
@@ -582,24 +582,24 @@ async function configureApp(app, auditSource) {
     assert.strictEqual(typeof auditSource, 'object');
 
     let appDomains = [];
-    appDomains.push({ domain: app.domain, fqdn: app.fqdn, type: 'primary' });
+    appDomains.push({ domain: app.domain, fqdn: app.fqdn, type: apps.SUBDOMAIN_TYPE_PRIMARY });
 
     app.redirectDomains.forEach(function (redirectDomain) {
-        appDomains.push({ domain: redirectDomain.domain, fqdn: redirectDomain.fqdn, type: 'alternate' });
+        appDomains.push({ domain: redirectDomain.domain, fqdn: redirectDomain.fqdn, type: apps.SUBDOMAIN_TYPE_REDIRECT });
     });
 
     app.aliasDomains.forEach(function (aliasDomain) {
-        appDomains.push({ domain: aliasDomain.domain, fqdn: aliasDomain.fqdn, type: 'alias' });
+        appDomains.push({ domain: aliasDomain.domain, fqdn: aliasDomain.fqdn, type: apps.SUBDOMAIN_TYPE_ALIAS });
     });
 
     for (const appDomain of appDomains) {
         const { bundle } = await ensureCertificate(appDomain.fqdn, appDomain.domain, auditSource);
 
-        if (appDomain.type === 'primary') {
+        if (appDomain.type === apps.SUBDOMAIN_TYPE_PRIMARY) {
             await writeAppNginxConfig(app, appDomain.fqdn, bundle);
-        } else if (appDomain.type === 'alternate') {
+        } else if (appDomain.type === apps.SUBDOMAIN_TYPE_REDIRECT) {
             await writeAppRedirectNginxConfig(app, appDomain.fqdn, bundle);
-        } else if (appDomain.type === 'alias') {
+        } else if (appDomain.type === apps.SUBDOMAIN_TYPE_ALIAS) {
             await writeAppNginxConfig(app, appDomain.fqdn, bundle);
         }
     }
@@ -640,16 +640,16 @@ async function renewCerts(options, auditSource, progressCallback) {
     for (const app of allApps) {
         if (app.runState === apps.RSTATE_STOPPED) continue; // do not renew certs of stopped apps
 
-        appDomains.push({ domain: app.domain, fqdn: app.fqdn, type: 'primary', app: app, nginxConfigFilename: path.join(paths.NGINX_APPCONFIG_DIR, app.id + '.conf') });
+        appDomains.push({ domain: app.domain, fqdn: app.fqdn, type: apps.SUBDOMAIN_TYPE_PRIMARY, app: app, nginxConfigFilename: path.join(paths.NGINX_APPCONFIG_DIR, app.id + '.conf') });
 
         app.redirectDomains.forEach(function (redirectDomain) {
             const nginxConfigFilename = path.join(paths.NGINX_APPCONFIG_DIR, `${app.id}-redirect-${redirectDomain.fqdn}.conf`);
-            appDomains.push({ domain: redirectDomain.domain, fqdn: redirectDomain.fqdn, type: 'alternate', app: app, nginxConfigFilename });
+            appDomains.push({ domain: redirectDomain.domain, fqdn: redirectDomain.fqdn, type: apps.SUBDOMAIN_TYPE_REDIRECT, app: app, nginxConfigFilename });
         });
 
         app.aliasDomains.forEach(function (aliasDomain) {
             const nginxConfigFilename = path.join(paths.NGINX_APPCONFIG_DIR, `${app.id}-alias-${aliasDomain.fqdn.replace('*', '_')}.conf`);
-            appDomains.push({ domain: aliasDomain.domain, fqdn: aliasDomain.fqdn, type: 'alias', app: app, nginxConfigFilename });
+            appDomains.push({ domain: aliasDomain.domain, fqdn: aliasDomain.fqdn, type: apps.SUBDOMAIN_TYPE_ALIAS, app: app, nginxConfigFilename });
         });
     }
 
@@ -676,11 +676,11 @@ async function renewCerts(options, auditSource, progressCallback) {
         // reconfigure since the cert changed
         if (appDomain.type === 'webadmin' || appDomain.type === 'webadmin+mail') {
             await writeDashboardNginxConfig(bundle, `${settings.dashboardFqdn()}.conf`, settings.dashboardFqdn());
-        } else if (appDomain.type === 'primary') {
+        } else if (appDomain.type === apps.SUBDOMAIN_TYPE_PRIMARY) {
             await writeAppNginxConfig(appDomain.app, appDomain.fqdn, bundle);
-        } else if (appDomain.type === 'alternate') {
+        } else if (appDomain.type === apps.SUBDOMAIN_TYPE_REDIRECT) {
             await writeAppRedirectNginxConfig(appDomain.app, appDomain.fqdn, bundle);
-        } else if (appDomain.type === 'alias') {
+        } else if (appDomain.type === apps.SUBDOMAIN_TYPE_ALIAS) {
             await writeAppNginxConfig(appDomain.app, appDomain.fqdn, bundle);
         } else {
             throw new BoxError(BoxError.INTERNAL_ERROR, `Unknown domain type for ${appDomain.fqdn}. This should never happen`);