diff --git a/core/server/services/members/config.js b/core/server/services/members/config.js
index 017af9bd01..23b5cf0e8a 100644
--- a/core/server/services/members/config.js
+++ b/core/server/services/members/config.js
@@ -1,8 +1,14 @@
+const errors = require('@tryghost/errors');
+const tpl = require('@tryghost/tpl');
 const {URL} = require('url');
 const crypto = require('crypto');
 const createKeypair = require('keypair');
 const path = require('path');
 
+const messages = {
+    incorrectKeyType: 'type must be one of "direct" or "connect".'
+};
+
 class MembersConfigProvider {
     /**
      * @param {object} options
@@ -92,7 +98,7 @@ class MembersConfigProvider {
      */
     getStripeKeys(type) {
         if (type !== 'direct' && type !== 'connect') {
-            throw new Error();
+            throw new errors.IncorrectUsageError(tpl(messages.incorrectKeyType));
         }
 
         const secretKey = this._settingsCache.get(`stripe_${type === 'connect' ? 'connect_' : ''}secret_key`);
diff --git a/core/server/services/members/importer/importer.js b/core/server/services/members/importer/importer.js
index d460f95ed9..83180ad963 100644
--- a/core/server/services/members/importer/importer.js
+++ b/core/server/services/members/importer/importer.js
@@ -2,6 +2,8 @@ const moment = require('moment-timezone');
 const path = require('path');
 const fs = require('fs-extra');
 const membersCSV = require('@tryghost/members-csv');
+const errors = require('@tryghost/errors');
+const tpl = require('@tryghost/tpl');
 const GhostMailer = require('../../mail').GhostMailer;
 const urlUtils = require('../../../../shared/url-utils');
 const db = require('../../../data/db');
@@ -9,6 +11,11 @@ const emailTemplate = require('./email-template');
 const jobsService = require('../../jobs');
 const labsService = require('../../../../shared/labs');
 
+const messages = {
+    filenameCollision: 'Filename already exists, please try again.',
+    jobAlreadyComplete: 'Job is already complete.'
+};
+
 const ghostMailer = new GhostMailer();
 module.exports = class MembersCSVImporter {
     /**
@@ -71,7 +78,7 @@ module.exports = class MembersCSVImporter {
         const pathExists = await fs.pathExists(outputFilePath);
 
         if (pathExists) {
-            throw new Error('Maybe we need better name generation');
+            throw new errors.DataImportError(tpl(messages.filenameCollision));
         }
 
         const rows = await membersCSV.parse(inputFilePath, headerMapping, defaultLabels);
@@ -102,7 +109,7 @@ module.exports = class MembersCSVImporter {
         const job = await this.getJob(id);
 
         if (job.status === 'complete') {
-            throw new Error('Job is already complete');
+            throw new errors.BadRequestError(tpl(messages.jobAlreadyComplete));
         }
 
         const rows = membersCSV.parse(job.filename);
@@ -178,8 +185,8 @@ module.exports = class MembersCSVImporter {
                 };
             } catch (error) {
                 // The model layer can sometimes throw arrays of errors
-                const errors = [].concat(error);
-                const errorMessage = errors.map(({message}) => message).join(', ');
+                const errorList = [].concat(error);
+                const errorMessage = errorList.map(({message}) => message).join(', ');
                 await trx.rollback();
                 return {
                     ...resultAccumulator,
diff --git a/core/server/services/members/service.js b/core/server/services/members/service.js
index 33fa24339a..bda20885b6 100644
--- a/core/server/services/members/service.js
+++ b/core/server/services/members/service.js
@@ -1,3 +1,5 @@
+const errors = require('@tryghost/errors');
+const tpl = require('@tryghost/tpl');
 const MembersSSR = require('@tryghost/members-ssr');
 const db = require('../../data/db');
 const MembersConfigProvider = require('./config');
@@ -12,6 +14,12 @@ const config = require('../../../shared/config');
 const ghostVersion = require('@tryghost/version');
 const _ = require('lodash');
 
+const messages = {
+    noLiveKeysInDevelopment: 'Cannot use live stripe keys in development. Please restart in production mode.',
+    sslRequiredForStripe: 'Cannot run Ghost without SSL when Stripe is connected. Please update your url config to use "https://".',
+    remoteWebhooksInDevelopment: 'Cannot use remote webhooks in development. See https://ghost.org/docs/webhooks/#stripe-webhooks for developing with Stripe.'
+};
+
 // Bind to settings.edited to update systems based on settings changes, similar to the bridge and models/base/listeners
 const events = require('../../lib/common/events');
 
@@ -69,16 +77,16 @@ const membersService = {
         if (env !== 'production') {
             if (!process.env.WEBHOOK_SECRET && membersConfig.isStripeConnected()) {
                 process.env.WEBHOOK_SECRET = 'DEFAULT_WEBHOOK_SECRET';
-                logging.warn('Cannot use remote webhooks in development. See https://ghost.org/docs/webhooks/#stripe-webhooks for developing with Stripe.');
+                logging.warn(tpl(messages.remoteWebhooksInDevelopment));
             }
 
             if (paymentConfig && paymentConfig.secretKey.startsWith('sk_live')) {
-                throw new Error('Cannot use live stripe keys in development. Please restart in production mode.');
+                throw new errors.IncorrectUsageError(tpl(messages.noLiveKeysInDevelopment));
             }
         } else {
             const siteUrl = urlUtils.getSiteUrl();
             if (!/^https/.test(siteUrl) && membersConfig.isStripeConnected()) {
-                throw new Error('Cannot run Ghost without SSL when Stripe is connected. Please update your url config to use "https://"');
+                throw new errors.IncorrectUsageError(tpl(messages.sslRequiredForStripe));
             }
         }
     },
diff --git a/core/server/services/members/stripe-connect.js b/core/server/services/members/stripe-connect.js
index ab9545a9a7..4dd27f6cc1 100644
--- a/core/server/services/members/stripe-connect.js
+++ b/core/server/services/members/stripe-connect.js
@@ -1,7 +1,13 @@
+const errors = require('@tryghost/errors');
+const tpl = require('@tryghost/tpl');
 const {Buffer} = require('buffer');
 const {randomBytes} = require('crypto');
 const {URL} = require('url');
 
+const messages = {
+    incorrectState: 'State did not match.'
+};
+
 const STATE_PROP = 'stripe-connect-state';
 
 const liveClientID = 'ca_8LBuZWhYshxF0A55KgCXu8PRTquCKC5x';
@@ -45,7 +51,7 @@ async function getStripeConnectOAuthUrl(setSessionProp, mode = 'live') {
  * @param {string} encodedData - A string encoding the response from Stripe Connect
  * @param {(prop: string) => Promise<any>} getSessionProp - A function to retrieve data from the current session
  *
- * @returns {Promise<{secret_key: string, public_key: string, livemode: boolean}>}
+ * @returns {Promise<{secret_key: string, public_key: string, livemode: boolean, display_name: string, account_id: string}>}
  */
 async function getStripeConnectTokenData(encodedData, getSessionProp) {
     const data = JSON.parse(Buffer.from(encodedData, 'base64').toString());
@@ -53,7 +59,7 @@ async function getStripeConnectTokenData(encodedData, getSessionProp) {
     const state = await getSessionProp(STATE_PROP);
 
     if (state !== data.s) {
-        throw new Error('State did not match');
+        throw new errors.NoPermissionError(tpl(messages.incorrectState));
     }
 
     return {