Gmail API Send Email: A Comprehensive Guide for Developers

The Gmail API is a powerful tool provided by Google, enabling developers to interact programmatically with Gmail mailboxes. With the Gmail API, developers can read, compose, send, and manage emails directly within their applications, offering a seamless integration with Gmail’s vast ecosystem.

Understand API for Gmail

This API is particularly beneficial for software developers working on customer relationship management (CRM) systems, applicant tracking systems (ATS), integration platform as a service (iPaaS) solutions, and outreach tools. By leveraging the Gmail API, these systems can automate email processes, enhance communication workflows, and provide a more integrated user experience.

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What is Gmail API Send Email?

enable gmail api

Sending emails via the Gmail API involves using HTTP requests to interact with Gmail’s backend systems. Instead of manually composing and sending emails through the Gmail interface, developers can automate the process within their applications.

The API provides endpoints that allow developers to create and send email messages in various formats, including plain text, HTML, and emails with attachments. It also supports more advanced features like threading and managing email labels, making it a comprehensive solution for programmatic email communication.

enable gmail api

Why Use Gmail API for Sending Emails?

Using the Gmail API for sending emails offers several advantages:

send email

Automation
Automate routine email tasks, saving time and reducing manual errors.

send email

Customization
Customize email content dynamically based on user data or application state.

send email

Integration
Integrate email sending directly into your app’s workflow, enhancing user experience.

send email

Scalability
Efficiently manage high-volume email sending, ideal for applications that require large-scale email communication.

Setting Up Gmail API for Sending Emails

1. Google's New OAuth Verification Process Overview

Google has a OAuth Verification process, mandating third-party applications to submit an application to Google for verifying their use of Google user data. You need to undergo Google’s app verification process, application whitelisting, and/or a security assessment.
While not experts in building and configuring Google Projects, we aim to assist you based on our experience in supporting other Unipile clients through the verification process
Feel free to reach out for guidance as you navigate through the ever-changing terrain of Google’s requirements and ensure a seamless integration of Google APIs into your application via Unipile.

To begin your development, you must complete the initial phase, which involves “Creating a Google Developers Console Account and Project”. Once your development is complete, you can then proceed to the second phase: “Generate your Demonstration Video”. Following that, you can move on to “Whitelisting & Security Review for Restricted Scopes”.

2. Create Google Developers Console Account and Project

Sign up on the Google Developers Console and either create a new project or use an existing Google project.

3. Navigation Menu - APIs & Services - 'Credentials'

Navigate to the ‘Credentials’ section in the Google Developers Console.
Create ‘OAuth Client ID’ credentials to gain access to your enabled APIs:
Application type: Web application
Name: Your internal name
Add 2 Authorised redirect URIs:
https://{{YOUR_DSN}}/api/v1/hosted/google_auth_request_callback (you can find your DSN in top right of Unipile Dashboard, example https://api1.unipile.com:13211/api/v1/hosted/google_auth_request_callback
https://{{YOUR_DSN less port}}/api/v1/hosted/google_auth_request_callback/port{{YOUR_DSN less domain}} (you can find your DSN in top right of Unipile Dashboard, example https://api1.unipile.com/api/v1/hosted/google_auth_request_callback/port13211

Click “CREATE”
Add Client ID and Client Secret to Unipile Dashboard > Settings > Google OAuth

4. Navigation Menu - APIs & Services - Library

Go to the ‘Library’ section in the Google Developers Console.
Enable Required API Libraries:
Search for and enable all API Libraries that your application will need: Gmail API

6. Navigation Menu - APIs & Services - OAuth Consent Screen

Throughout the implementation, you may keep your Google Project in different states:

‘User Type’ as ‘Internal’: In this mode, your app is limited to Google Workspace users within your organization.
‘User Type’ as ‘External’ & ‘Publishing Status’ as ‘In Testing’:
Note: While ‘In Testing,’ you need to add Test Users. Tokens expire in 7 days and require users to re-authenticate.
For more information on Publishing Status, click here.
For details on User Types, click here.

Ensure that you select the appropriate User Type and Publishing Status based on your project’s testing and deployment phase.

5. Navigation Menu - APIs & Services - Enabled APIS and Services

Access the ‘Enabled APIS and Services’ section in the Google Developers Console.
Check Enabled APIs: Review and verify the full list of APIs you have enabled within your Google Project.
The Dashboard provides an overview of all the enabled APIs, allowing you to confirm the status of your selected APIs for your project. Use this section to ensure that the necessary APIs are enabled for a seamless integration with your application.

 

7. OAuth Consent Screen Section - App Information

Ensure the following information is provided:

Enter Your Application Name: Specify your application name.
User Support Email: Include an email address for users to contact with questions about their consent. Recommend using an alias or distribution list with relevant parties included.
Add Your App Logo: Upload your application logo for visual identification.

Completing this information in the OAuth consent screen section is essential for users to understand and trust your application during the consent process. Include accurate details and branding elements for a smooth user experience.

8. OAuth consent screen section - App Domain

Provide the following information under the App Domain section:

Application Homepage URL: Add the URL for your application’s homepage.
Ensure that it is a true homepage and not just a ‘login’ page.
Application Privacy Policy Link: Include a link to your application’s Privacy Policy.
Important: Ensure your legal team reviews the Privacy Policy to meet Google’s specific requirements, particularly from the ‘Limited Use’ section of the provided document.
Application Terms of Service Link: Add a link to your application’s Terms of Service.

9. OAuth consent screen section - Authorized Domains

Follow these steps to add authorized domains:

  • Add your app domain utilized in your Google Project. Ensure your domain is the production-level one, not the dev/staging domain.
  • Add unipile.com domain

10. OAuth consent screen section - Developer Contact Information
  • Enter an Email Address:
    • Provide an email address for developer contact information.
    • Important: This should be a distribution list email address, ensuring all relevant parties receive Google Verification-related emails and notifications about any changes to your project. Keep this distribution list up-to-date as team members come and go.
  • Post-Verification Monitoring:
    • After submission for verification, closely monitor the Google project for any action items from Google.
    • Note: Google sends emails to this address, but they may end up in spam folders or be blocked by servers. Regularly check for updates to avoid missing important communications.

Make sure to enter an actively monitored and regularly checked email address to stay informed about your Google project’s status and any required actions post-verification.

11. Scopes section
Follow these steps to add required scopes:

  • Click on the ‘ADD OR REMOVE SCOPE ‘ button to access the menu.
  • Add the following scopes (if they don’t appear in the list, refresh the page) :
    ./auth/gmail.send
    ./auth/gmail.labels
    ./auth/gmail.readonly
    ./auth/gmail.modify (not needed if you dont want move or delete email. You will have to demonstrate to Google you really use it. Inform us to remove it on your Unipile account manually)

    12. Generate your Demonstration Video

    You may proceed with this step only once your integration is fully completed and operational in production.

    Produce and host a demonstration video that adheres to Google’s stipulations. To validate your app with Google, you must also submit a video showcasing your app’s functionality. This video should be uploaded as an ‘Unlisted’ YouTube video for verification purposes, and only one video link is permissible.

    Before crafting the video

    • Your app and OAuth flow are presented in English, as indicated in Google documentation under “Apps requesting sensitive scopes” and “Apps requesting restricted scopes.”
    • The demonstration is conducted in a production-level domain.
    • In your Google Project settings, navigate to Navigation Menu -> APIs & Services -> OAuth Consent Screen and confirm the following:
      • Publishing status is set to “In Production.”
      • User Type is designated as “External.”
    Authentication
    • Display your application’s homepage with the complete URL, emphasizing its production status.
    • Illustrate how a Google customer can connect their account emphasizing the use of the official Google sign-in button.
    • During the authentication flow, when presenting the OAuth process screen, highlight the URL and drag across to reveal the CLIENT ID in the URL.
    Functionality
    • Sequentially showcase each set of scopes being requested, tailoring them to your specific use case.
    • Demonstrate bi-directional functionality by showing synchronization between your application and Gmail. Use separate tabs to toggle between your application and each relevant section of Gmail. For example, sending an email through your application, illustrating how changes are synced in Sent mail list on Gmail, and in the other way displaying the receipt of an incoming email within your app.

    By following these guidelines, your demo video will effectively convey the authentication process and the functional capabilities of your application in sync with Google services.

    After creating your video demo and ensuring it complies with all the criteria outlined, kindly share the YouTube video URL with your us. We can assist in the review process or you can proceed to submit your app for verification directly.

    Please note the following steps:

    • Add the final video to your Google Project as an ‘unlisted’ YouTube video link.
    • Submit the YouTube video URL to your Customer Success Manager for review.
    • Following the review, proceed with the app verification submission.

    Keep in mind that the verification process duration may vary. After submission, it can take anywhere from 2 to 8 weeks, depending on Google’s submission queue and the number of remediation rounds they deem necessary. Stay informed and coordinate with us throughout the verification process.

    13. Whitelisting & Security Review for Restricted Scopes

    If your application utilizes restricted scopes, additional steps are required. Here’s a brief overview of what to anticipate:

    Google Security Assessment
    To ensure the security of user data, apps requesting access to restricted scope Google user data must undergo a security assessment. This assessment is crucial for verifying that all apps accessing Google user data can handle data securely and delete user data upon request. The detailed assessment process is outlined on the CASA (Cloud Application Security Assessment) site.

    Google categorizes your app as either Tier 2 or Tier 3

    Tier 2 (Self Scanned – Lab Verified) >> Most Common
    Option of Free OR paid (third-party assessor)
    CASA Tier 2 Process
    Tier 3 (Lab Scanned – Lab Verified)
    Paid – Must be completed by a third-party assessor
    After receiving your Tier classification, Google will provide instructions and tools for completing the assessment. Refer to the provided link for Google Security Assessment Information and scroll down to the Security Assessment FAQs for more detailed information. Ensure compliance with this process to demonstrate your app’s capability in handling user data securely when utilizing restricted scopes.

    Google Security Assessment Information

    Yearly Security Re-assessment for Apps with Restricted Scopes
    Apps that access restricted scopes must undergo a yearly re-verification process for compliance and complete a security assessment every 12 months to maintain access to verified restricted scopes. This process ensures ongoing adherence to security standards and safeguards user data.

    If, at any point, you introduce a new restricted scope that hasn’t been previously assessed and approved, your app may require reassessment at that time.

    The Google review team will initiate contact via email when it’s time for your app to recertify. It is crucial to keep your Project Owner and Project Editor information up-to-date in your Cloud Console. This ensures that the right members of your team receive notifications about this annual enforcement, allowing for timely and smooth compliance with the re-assessment requirements. Stay vigilant and promptly respond to communications from Google to uphold the security and compliance of your app. Check Google FAQ for more information.

    Whitelisting Option
    If you prefer an alternative to the standard verification and security review processes, you have the option to have your application whitelisted. This allows you to bypass the usual procedures, but it is important to note that this option is applicable only if your application meets very specific criteria. While most use cases do not fulfill these criteria, we have outlined the requirements below for you to assess whether whitelisting might be suitable for your application.

    Requirements:

    Majority of Customers using Google Workspace:
    The majority of your customers should use Google Workspace (formerly GSuite) accounts, i.e., have email addresses with the format @company.com.
    Whitelisting requires action by end users’ administrators to allow access. You need to provide to your users’ administrators your Google projet Client ID. They have open their Console: https://admin.google.com/ac/owl/list?tab=configuredApps and allow you client_id.
    Limited Personal Gmail Account Usage:
    Fewer than 100 personal Gmail accounts (@gmail.com addresses) should be able to authenticate into this flow.
    Unverified projects have a 100 (lifetime) user limit per project. When whitelisted, Google Workspace accounts do not count against this limit. However, personal Gmail accounts will always count towards this limit.
    Free Trial Users and Whitelisting:
    Free trial users must use their Workspace email address and whitelist the application.
    Keep in mind that whitelisting is a workaround solution and might not be suitable for all use cases. Evaluate these requirements carefully to determine if your application aligns with the criteria for whitelisting. If so, take the necessary steps to meet these requirements and explore this alternative approach.

    Leveraging Gmail API Send Email Features for CRM, ATS, Outreach Tools, and iPaaS

    CRM Systems

    The Gmail API allows CRM platforms to automate email communication, track interactions, and enhance customer engagement. By using the list email and start new email features, CRMs can automatically log customer emails, send personalized messages, and ensure all communication is centralized within the system.

    ATS Platforms

    enable gmail api

    Applicant Tracking Systems (ATS) can utilize the Gmail API to streamline candidate communication. Features like webhook notifications and email list management ensure timely updates on applicant interactions, automate bulk email sending, and help recruiters stay organized by categorizing emails with labels.

    enable gmail api

    iPaaS Solutions

    Integration Platform as a Service (iPaaS) solutions can integrate the Gmail API to automate email-based workflows across different applications. By leveraging the list and get label features, iPaaS platforms can categorize emails, trigger specific workflows, and ensure smooth data integration across connected systems, enhancing overall operational efficiency.

    What Are the Key Features of Gmail API Send Email?

    The Gmail API Send Email offers essential features like listing emails, starting new emails, managing labels through list and get operations, and setting up webhook notifications for real-time updates. These capabilities streamline email management and integration for developers.

    List All Emails

    list email gmail api

    Easily retrieve and display a list of emails from a user’s Gmail account, enabling efficient email management and search functionality within your application.

    Start New Email

    Programmatically compose and send new emails directly from your app, automating communication and improving user engagement.

    List and Get Label

    Manage Gmail labels by listing and retrieving label details, helping organize and categorize emails for better workflow management.

    Webhook

    Set up webhook notifications to receive real-time updates on email activity, ensuring timely responses and actions within your application.

    Why Use Gmail API for Integrating Advanced Email Features?

    Integrating advanced email features into your applications is made swift and effortless with Unipile’s provision of ready-to-use code snippets. Developers can now bypass the intricacies of starting from scratch, leveraging these pre-written codes to quickly tap into the full suite of Gmail API functionalities. Whether it’s automating email flows, parsing email data, or syncing with other software, Unipile’s reliable codebase serves as a springboard to a rapid and seamless integration, ensuring a shorter development cycle and a smoother path to deployment. This practical approach not only saves valuable coding hours but also reduces the complexity of implementing sophisticated email solutions.

    1 Icon

    Connect your users accounts
    Provide users with access to connect their accounts through just one API call, which generates a secure, direct login link for them.

    deliverability Icon

    Get and list user emails in your app
    Select the methods for retrieving data and implementing the message history feature in your app, ensuring real-time synchronization.

    Discover the Full Range of Unipile’s Gmail Integration Capabilities

    Email Features

    Gmail
    Gmail

    Outlook
    Outlook

    IMAP
    IMAP

    Account connection
    Hosted Auth: White label email auth Check Check Check
    Custom auth: Connect user with credentials Check
    Gmail or Microsoft OAuth: Use your App Oauth screen Check Check
    Send/Receive
    Email sending API Check Check Check
    Email listing API Check Check Check
    Organize
    Email deletion API Check Check Check
    Email moving API Check Check Check
    Email folder listing API Check Check Check
    Email folder retrieval API Check Check Check
    Webhooks
    Email webhook for new messages Check Check Check
    Email open and click tracking API Check Check Check

    Unipile vs Self-Integration: Save Time and Get Support

    Discover the clear advantages of choosing Unipile’s streamlined integration services over managing the process independently. With Unipile’s Hosted Auth, you can boost your system’s security by centralizing the management of sensitive credentials and achieve seamless integration across various email providers with universal compatibility. This approach not only reduces maintenance efforts but also accelerates development, ensuring a reliable, efficient, and user-friendly authentication experience with just a single link.

    One Link Hosted Auth vs. Full OAuth Flow

    Unipile’s Hosted Auth simplifies the email integration process by automating the detection and authentication of email providers. This drastically cuts down on development complexity and saves significant time. By optimizing the initial setup, this modern method guarantees ongoing reliability and security of your connections, allowing developers to focus on improving the user experience rather than dealing with backend challenges.

    Future of Gmail API in Software Development

    Trends in API-Driven Email Communication

    Personalization: Expect more advanced personalization features as APIs integrate with AI and machine learning tools.

    Automation: Increased use of automation for tasks like email sequencing and A/B testing.

    The Role of AI and Machine Learning in Gmail API

    AI and machine learning are set to revolutionize how Gmail API is used:

    Predictive Analytics: AI can help predict the best times to send emails and the likelihood of a response.

    Content Optimization: Machine learning algorithms can suggest improvements to email content for better engagement.

    Expanding Versatility: Unipile’s Integration with Microsoft and IMAP

    Microsoft Graph API

    microsoft oauth api

    To link Microsoft accounts with Unipile using OAuth, first register your application in Azure Active Directory (AAD). Then, configure Unipile to work with your AAD application ID. Should any issues arise during the setup or registration with Azure AD, our support team is on hand to offer prompt assistance and comprehensive instructions.

    IMAP API

    microsoft oauth api

    For integrating IMAP accounts with Unipile, start by configuring your server settings and choosing the appropriate authentication method within Unipile. Next, input the necessary IMAP server details to establish a connection. If you encounter any issues during configuration, our support team is available to guide you through the process, ensuring a successful integration.

    FAQs

    What is Gmail API Send Email and how does it work?

    Gmail API Send Email allows developers to send emails programmatically using HTTP requests. This feature enables the creation and sending of emails in various formats, including plain text, HTML, and emails with attachments, directly from within applications.

    Why should developers use the Gmail API for sending emails instead of other methods?

    Using the Gmail API for sending emails offers automation, customization, seamless integration into workflows, and scalability. This makes it ideal for managing large-scale email communications efficiently and reducing manual errors.

    How can I set up the Gmail API for sending emails in my application?

    To set up the Gmail API, you need to create a project in the Google Developers Console, enable the Gmail API, and configure OAuth credentials for authentication. This setup process allows your application to securely interact with Gmail’s backend systems.

    What are the key features of Gmail API Send Email that benefit CRM, ATS, and iPaaS tools?

    Key features include listing emails, starting new emails, managing labels, and setting up webhook notifications. These features streamline email management, automate communications, and enhance integration capabilities in CRM, ATS, and iPaaS tools.

    What challenges might developers face when integrating advanced email features with the Gmail API?

    Developers might encounter challenges such as managing OAuth authentication, handling API quotas, and ensuring secure transmission of email data. However, using pre-written code snippets and following best practices can simplify the integration process.

    How does Gmail API support the future of email communication in software development?

    Gmail API is evolving with trends in personalization and automation. Integrating AI and machine learning with the Gmail API enables predictive analytics, content optimization, and more sophisticated email management, driving the future of API-driven communication in software development.

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