Creating a Gmail integration using custom connectors

Creating a Gmail integration using custom connectors

Hello everyone!

Greetings from Deluge. Following up on our series aimed at exploring the capabilities of Deluge, today we'll take an in-depth look into the Deluge custom connections that can be created across Zoho services.

Deluge boasts an extensive range of over 260 built-in integrations spanning more than 35 Zoho services. These integrations streamline data access and modification with these services, from a single point in Zoho, without having to toggle between services. However, we understand that the needs of our users vary widely, and sometimes existing integrations may not cover every scenario.

That's where custom connections come in. Think of them as the Swiss Army Knife of integrations, enabling connections with hundreds of services—such as Gmail and Outlook—and seamlessly integrating them with your favorite Zoho services. With custom connections, you have the power to build your own integrations with virtually any third-party service and tailor them to meet your requirements. Moreover, since the custom connections use the OAuth 2.0 authentication mechanism, you're getting best-in-class security while integrating with third-party services.

What are connections? 
Before we dive into the details of custom connectors, let's take a glimpse at what connections are in Deluge. Connections are a means to connect your Zoho account and any third-party accounts you wish to integrate with. Once a connection is created and connected, you can use it in Deluge integration tasks or invokeURL scripts to perform REST operations on the target service from the required Zoho service. For more information, visit our Connections help doc.
Use case 
Assume the sales team of an organization uses Zoho CRM for managing leads, customer retention, and customer acquisition, and uses Gmail for communication purposes, like following up with potential clients via email.   While the system works as is, it's time-consuming and prone to error, so an integration between Gmail and Zoho CRM is necessary to improve efficiency.

A custom connection to your Google account will enable you to sync your Zoho CRM and Google accounts, allowing you to perform actions related to your Google account from Zoho CRM. For example, you can invoke the connection using the invokeURL task in Zoho CRM and send an email to your leads from your Gmail address.

Steps to configure the Google custom connection

Configuration video

Configuration steps
Creating Google OAuth credentials
  1. Visit
  2. Click the dropdown and choose the required project.
  3. Navigate to the hamburger menu on the left and click APIs and services -> Library.
  4. You'll be taken to the API library page. Navigate to the Google Workspace section and click Gmail API.
  5. Next, click Enable on the Gmail API product details page.
  6. In order to use this API, you'll need to create credentials. Click CREATE CREDENTIALS.
  7. On the Create credentials page, choose Gmail API in the Select an API dropdown and User Data under the What data will you be accessing? section. Click Next.
  8. Next, on the OAuth consent screen, enter the App name, User support email, and Developer contact email address. Then click Save and Continue.
  9. Next, under the Scopes section, click the ADD OR REMOVE SCOPES button.
  10. In the Update selected scopes pane, search and select the gmail.readonly scope. Click Update, and then click Save and continue.

  11. Now, under the OAuth Client ID section, choose Web application in the Application type dropdown. Then name your app.

  12. Enter as the Authorized redirect URI.
  13. Click Create and download your credentials. This Client ID and others will be required later, while creating a connection in Zoho CRM.
  14. Navigate to the OAuth consent screen and click Add users under Test users. Enter the user's email address and click Save.
Creating a custom connector for Gmail
  1. Now the action shifts to Zoho CRM. Navigate to -> Settings -> Connections.
  2. Choose Custom Services and click Create Service.
  3. On the Create Service screen, choose OAuth 2.0 as the Authentication type and Header as the Parameter.
  4. Enter the Client ID, Client Secret, and Authorize URL generated from Google as shown in step 12 above.
    Tip: Having the Offline access type will allow your application to refresh tokens even when the user is not actively using the application.
  5. Then enter as the Access token URL and Refresh token URL.
  6. Specify the necessary scopes like read and create, etc. and then click Create Service.
  7. On the next page, click Create Connection. Give the connection name and choose the scopes. Then click Create and Connect.
  8. Finally, authenticate the connection on the Google accounts page. Your custom connection will be created, and the two services can be integrated!
Now that the connection between Zoho CRM and Gmail has been established, you can use the invokeURL task to access and modify data in Gmail using the different APIs.

You can use the below code in invokeURL task to get the latest emails from Gmail.

userId = "";
get_gmail = invokeurl
url: ""+userId+"/messages"
type: GET
connection : "connectionname"
messageID = get_gmail.get("messages").get(0).get("id");

get_gmail_withID = invokeurl
url: ""+userId+"/messages/"+messageID
type: GET
connection : "connectionname"

Content_of_the_mail = get_gmail_withID.get("snippet");
info "Mail Content : " + Content_of_the_mail;

gmail_values = get_gmail_withID.get("payload").get("headers");
for each headers in gmail_values
if ( headers.get("name") == "Subject" )
info "Subject of the Mail : " + headers.get("value");
if ( headers.get("name") == "From" )
info "From Address : " + headers.get("value");



And that's a wrap for today! We hope you found this post informative and start using custom connections to experience the full capabilities of Deluge and Zoho.

Kindly let us know if you have any questions, feedback, or suggestions in the comments, or write to us at!
The Deluge Team

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