diff --git a/packages/nodes-base/credentials/MailchimpApi.credentials.ts b/packages/nodes-base/credentials/MailchimpApi.credentials.ts
index e2e98964da..c6a6462bc1 100644
--- a/packages/nodes-base/credentials/MailchimpApi.credentials.ts
+++ b/packages/nodes-base/credentials/MailchimpApi.credentials.ts
@@ -13,11 +13,5 @@ export class MailchimpApi implements ICredentialType {
 			type: 'string' as NodePropertyTypes,
 			default: '',
 		},
-		{
-			displayName: 'Datacenter',
-			name: 'datacenter',
-			type: 'string' as NodePropertyTypes,
-			default: '',
-		},
 	];
 }
diff --git a/packages/nodes-base/nodes/Mailchimp/GenericFunctions.ts b/packages/nodes-base/nodes/Mailchimp/GenericFunctions.ts
index fdf44bdc82..6f0aeb0e8c 100644
--- a/packages/nodes-base/nodes/Mailchimp/GenericFunctions.ts
+++ b/packages/nodes-base/nodes/Mailchimp/GenericFunctions.ts
@@ -7,9 +7,8 @@ import {
 	IExecuteSingleFunctions
 } from 'n8n-core';
 
-export async function mailchimpApiRequest(this: IHookFunctions | IExecuteFunctions | IExecuteSingleFunctions | ILoadOptionsFunctions, resource: string, method: string, body: any = {}, headers?: object): Promise<any> { // tslint:disable-line:no-any
+export async function mailchimpApiRequest(this: IHookFunctions | IExecuteFunctions | IExecuteSingleFunctions | ILoadOptionsFunctions, endpoint: string, method: string, body: any = {}, headers?: object): Promise<any> { // tslint:disable-line:no-any
 	const credentials = this.getCredentials('mailchimpApi');
-	const datacenter = credentials!.datacenter as string;
 
 	if (credentials === undefined) {
 		throw new Error('No credentials got returned!');
@@ -17,13 +16,19 @@ export async function mailchimpApiRequest(this: IHookFunctions | IExecuteFunctio
 
 	const headerWithAuthentication = Object.assign({}, headers, { Authorization: `apikey ${credentials.apiKey}` });
 
-	const endpoint = 'api.mailchimp.com/3.0';
+	if (!(credentials.apiKey as string).includes('-')) {
+		throw new Error('The API key is not valid!');
+	}
+
+	const datacenter = (credentials.apiKey as string).split('-').pop();
+
+	const host = 'api.mailchimp.com/3.0';
 
 	const options: OptionsWithUri = {
 		headers: headerWithAuthentication,
 		method,
-		uri: `https://${datacenter}.${endpoint}${resource}`,
-		json: true
+		uri: `https://${datacenter}.${host}${endpoint}`,
+		json: true,
 	};
 
 	if (Object.keys(body).length !== 0) {
diff --git a/packages/nodes-base/nodes/Mailchimp/Mailchimp.node.ts b/packages/nodes-base/nodes/Mailchimp/Mailchimp.node.ts
index a214fd41de..187512ff29 100644
--- a/packages/nodes-base/nodes/Mailchimp/Mailchimp.node.ts
+++ b/packages/nodes-base/nodes/Mailchimp/Mailchimp.node.ts
@@ -1,26 +1,27 @@
+import * as moment from 'moment';
+
 import {
 	IExecuteSingleFunctions,
 } from 'n8n-core';
 import {
 	IDataObject,
+	ILoadOptionsFunctions,
 	INodeTypeDescription,
 	INodeExecutionData,
 	INodeType,
-	ILoadOptionsFunctions,
 	INodePropertyOptions,
 } from 'n8n-workflow';
 import {
 	mailchimpApiRequest,
-	validateJSON
+	validateJSON,
 } from './GenericFunctions';
-import * as moment from 'moment';
 
 enum Status {
 	subscribe = 'subscribe',
 	unsubscribed = 'unsubscribe',
 	cleaned = 'cleaned',
 	pending = 'pending',
-	transactional = 'transactional'
+	transactional = 'transactional',
 }
 
 interface ILocation {
@@ -78,7 +79,7 @@ export class Mailchimp implements INodeType {
 						description: 'Add member to list',
 					},
 				],
-				default: '',
+				default: 'member',
 				required: true,
 				description: 'Resource to consume.',
 			},
@@ -101,7 +102,7 @@ export class Mailchimp implements INodeType {
 						description: 'Create a new member on list',
 					},
 				],
-				default: '',
+				default: 'create',
 				description: 'The operation to perform.',
 			},
 			{
@@ -114,7 +115,7 @@ export class Mailchimp implements INodeType {
 				displayOptions: {
 					show: {
 						resource: [
-							'member'
+							'member',
 						],
 						operation: [
 							'create',
@@ -124,7 +125,7 @@ export class Mailchimp implements INodeType {
 				default: '',
 				options: [],
 				required: true,
-				description: 'List of lists'
+				description: 'List of lists',
 			},
 			{
 				displayName: 'Email',
@@ -215,7 +216,7 @@ export class Mailchimp implements INodeType {
 				displayOptions: {
 					show: {
 						resource:[
-							'member'
+							'member',
 						],
 						operation: [
 							'create',
@@ -298,12 +299,12 @@ export class Mailchimp implements INodeType {
 				name: 'locationFieldsUi',
 				type: 'fixedCollection',
 				placeholder: 'Add Location',
-				default: false,
+				default: {},
 				description: `Subscriber location information.n`,
 				displayOptions: {
 					show: {
 						resource:[
-							'member'
+							'member',
 						],
 						operation: [
 							'create',
@@ -324,7 +325,7 @@ export class Mailchimp implements INodeType {
 								type: 'string',
 								required: true,
 								description: 'The location latitude.',
-								default: ''
+								default: '',
 							},
 							{
 								displayName: 'Longitude',
@@ -332,7 +333,7 @@ export class Mailchimp implements INodeType {
 								type: 'string',
 								required: true,
 								description: 'The location longitude.',
-								default: ''
+								default: '',
 							},
 						],
 					}
@@ -343,7 +344,7 @@ export class Mailchimp implements INodeType {
 				name: 'mergeFieldsUi',
 				placeholder: 'Add Merge Fields',
 				type: 'fixedCollection',
-				default: '',
+				default: {},
 				typeOptions: {
 					multipleValues: true,
 				},
@@ -366,19 +367,19 @@ export class Mailchimp implements INodeType {
 						name: 'mergeFieldsValues',
 						displayName: 'Field',
 						typeOptions: {
-							multipleValueButtonText: 'Add Field'
+							multipleValueButtonText: 'Add Field',
 						},
 						values: [
 							{
-								displayName: 'Merge Field Name',
+								displayName: 'Field Name',
 								name: 'name',
 								type: 'string',
 								required: true,
 								description: 'Merge Field name',
-								default: ''
+								default: '',
 							},
 							{
-								displayName: 'Merge Field Value',
+								displayName: 'Field Value',
 								name: 'value',
 								required: true,
 								type: 'string',
@@ -394,20 +395,20 @@ export class Mailchimp implements INodeType {
 				name: 'mergeFieldsJson',
 				type: 'json',
 				typeOptions: {
-					alwaysOpenEditWindow: true
+					alwaysOpenEditWindow: true,
 				},
 				default: '',
 				description: '',
 				displayOptions: {
 					show: {
 						resource:[
-							'member'
+							'member',
 						],
 						operation: [
 							'create',
 						],
 						jsonParameters: [
-							true
+							true,
 						],
 					},
 				},
@@ -417,20 +418,20 @@ export class Mailchimp implements INodeType {
 				name: 'locationJson',
 				type: 'json',
 				typeOptions: {
-					alwaysOpenEditWindow: true
+					alwaysOpenEditWindow: true,
 				},
 				default: '',
 				description: '',
 				displayOptions: {
 					show: {
 						resource:[
-							'member'
+							'member',
 						],
 						operation: [
 							'create',
 						],
 						jsonParameters: [
-							true
+							true,
 						],
 					},
 				},
@@ -442,7 +443,6 @@ export class Mailchimp implements INodeType {
 	methods = {
 		loadOptions: {
 
-
 			// Get all the available lists to display them to user so that he can
 			// select them easily
 			async getLists(this: ILoadOptionsFunctions): Promise<INodePropertyOptions[]> {
@@ -552,7 +552,7 @@ export class Mailchimp implements INodeType {
 			}
 		}
 		return {
-			json: response
+			json: response,
 		};
 	}
 }
diff --git a/packages/nodes-base/package.json b/packages/nodes-base/package.json
index 4c1afc425f..8b87d9e255 100644
--- a/packages/nodes-base/package.json
+++ b/packages/nodes-base/package.json
@@ -42,8 +42,8 @@
             "dist/credentials/HttpHeaderAuth.credentials.js",
             "dist/credentials/Imap.credentials.js",
             "dist/credentials/LinkFishApi.credentials.js",
-			"dist/credentials/MailgunApi.credentials.js",
-			"dist/credentials/MailchimpApi.credentials.js",
+            "dist/credentials/MailchimpApi.credentials.js",
+            "dist/credentials/MailgunApi.credentials.js",
             "dist/credentials/MandrillApi.credentials.js",
             "dist/credentials/MattermostApi.credentials.js",
             "dist/credentials/MongoDb.credentials.js",
@@ -98,8 +98,8 @@
             "dist/nodes/If.node.js",
             "dist/nodes/Interval.node.js",
             "dist/nodes/LinkFish/LinkFish.node.js",
-			"dist/nodes/Mailgun/Mailgun.node.js",
-			"dist/nodes/Mailchimp/Mailchimp.node.js",
+            "dist/nodes/Mailchimp/Mailchimp.node.js",
+            "dist/nodes/Mailgun/Mailgun.node.js",
             "dist/nodes/Mandrill/Mandrill.node.js",
             "dist/nodes/Mattermost/Mattermost.node.js",
             "dist/nodes/Merge.node.js",