What are the best deliverability APIs to use?

Summary

A wide range of APIs are available for enhancing email deliverability, covering various aspects from sending and tracking to verification, testing, and monitoring. Email service providers like Mailjet, SendGrid, Postmark, SparkPost, Mailgun, AWS SES, Google Gmail, and Microsoft Outlook offer APIs for sending emails, tracking deliverability metrics, and managing contacts/queues. Specialized services like EmailConsul, Inbox Monster, ZeroBounce, Hunter.io, Email Hippo, GlockApps, MailerQ, Mailosaur, and Spam Resource provide APIs for email validation, list cleaning, deliverability testing, blocklist monitoring, seed list testing, and feedback loop processing. These APIs aim to improve inbox placement, sender reputation, and overall email performance.

Key findings

  • Comprehensive Solutions: Many APIs offer comprehensive solutions, including sending, tracking, and analytics, to manage email deliverability effectively.
  • Verification and Cleaning: Email verification and list cleaning APIs are crucial for maintaining a clean email list and improving sender reputation by removing invalid addresses.
  • Testing and Monitoring: Deliverability testing APIs help monitor inbox placement, identify deliverability issues, and improve email performance across various ISPs and blocklists.
  • Authentication: APIs from major providers offer configuration options for authentication protocols like SPF, DKIM, and DMARC to enhance sender reputation.
  • Feedback Loops: Some APIs automate feedback loop (FBL) processing, enabling senders to manage complaints and remove subscribers who mark emails as spam efficiently.

Key considerations

  • Specific Needs: Assess your specific needs and challenges related to email deliverability to choose the most suitable API.
  • Integration: Consider the ease of integration with your existing email infrastructure and workflows.
  • Scalability: Ensure the API can scale to accommodate future growth in email volume and complexity.
  • Pricing: Evaluate pricing models and plans to find a cost-effective solution that aligns with your budget.
  • Reporting and Analytics: Check the depth and quality of reporting and analytics provided by the API to identify and address deliverability issues effectively.
  • Authentication Protocols: Implement and properly configure authentication protocols like SPF, DKIM, and DMARC to maximize deliverability benefits.
  • Blocklist Monitoring and FBL: Ensure real-time monitoring of blocklists and efficient processing of feedback loops to promptly address any negative impact on your sender reputation.

What email marketers say
11Marketer opinions

Several APIs and services offer solutions for enhancing email deliverability. These solutions encompass email sending and tracking (Mailjet, SendGrid, Postmark, SparkPost, Mailgun), email verification and list cleaning (ZeroBounce, Hunter.io, Email Hippo), and deliverability testing (GlockApps). Some services like EmailConsul and Inbox Monster provide comprehensive API suites. Each API offers unique features for monitoring, managing, and optimizing email deliverability.

Key opinions

  • Diverse Solutions: A wide range of APIs cater to different aspects of email deliverability, from sending and tracking to verification and testing.
  • Comprehensive Suites: Some platforms provide comprehensive API suites, offering a one-stop solution for various deliverability needs.
  • Real-time Analytics: Many APIs offer real-time analytics to monitor email performance and identify potential issues.
  • Email Verification: Email verification and list cleaning APIs are crucial for maintaining a clean email list and improving sender reputation.
  • Testing and Monitoring: Deliverability testing APIs help monitor inbox placement and identify deliverability issues across different ISPs.

Key considerations

  • Specific Needs: Assess specific deliverability challenges (e.g., sending volume, list hygiene) to choose the most suitable API.
  • Feature Set: Evaluate the features offered by each API (e.g., tracking, analytics, verification) to ensure they align with requirements.
  • Integration: Consider the ease of integration with existing systems and workflows.
  • Scalability: Ensure the API can scale to accommodate future growth and increased email volume.
  • Pricing: Compare pricing models and plans to find a cost-effective solution.
Marketer view

Email marketer from Email Hippo shares that their email list cleaning API helps to identify and remove invalid or risky email addresses, improving deliverability and protecting sender reputation.

February 2022 - Email Hippo
Marketer view

Email marketer from Postmark focuses on transactional emails, offering an API with fast delivery, detailed analytics, and tools to monitor and improve deliverability for critical messages.

May 2023 - Postmark
Marketer view

Email marketer from SendGrid explains their Email API provides scalable infrastructure, deliverability tools, and real-time analytics to ensure emails reach their intended recipients.

May 2022 - SendGrid
Marketer view

Email marketer from SparkPost highlights their robust Email API which provides advanced deliverability features, real-time analytics, and global infrastructure to ensure high inbox placement rates.

December 2021 - SparkPost
Marketer view

Email marketer from Hunter.io talks about their Email Verification API, which helps ensure the accuracy of email addresses, reducing bounce rates and improving sender reputation.

October 2023 - Hunter.io
Marketer view

Marketer from Email Geeks shares that EmailConsul has an API with domain/IP monitoring, GP, SNDS, Seedlisting, DMARC, and ESP log monitoring.

June 2024 - Email Geeks
Marketer view

Marketer from Email Geeks mentions that Inbox Monster has a comprehensive suite of APIs and offers a demo of the solution.

April 2024 - Email Geeks
Marketer view

Email marketer from Mailgun shares that their Transactional Email API delivers reliable email sending, detailed analytics, and powerful features for managing email deliverability.

March 2024 - Mailgun
Marketer view

Email marketer from Mailjet Blog highlights their Send API, which allows users to send emails, track deliverability, and manage contacts, offering a comprehensive solution for email sending needs.

June 2022 - Mailjet Blog
Marketer view

Email marketer from GlockApps explains that their Email Deliverability Testing API helps monitor inbox placement, identify deliverability issues, and improve email performance across various ISPs.

June 2023 - GlockApps
Marketer view

Email marketer from ZeroBounce details that their Email Validation API offers real-time email verification, helping to improve deliverability by identifying and removing invalid email addresses.

November 2021 - ZeroBounce

What the experts say
3Expert opinions

Deliverability APIs offer several key features including real-time blocklist monitoring for quick identification and remediation of IP/domain listings, seed list testing to gain insights into inbox placement across different ISPs, and automated feedback loop (FBL) processing for efficient complaint management and subscriber removal.

Key opinions

  • Blocklist Monitoring: APIs enable real-time monitoring of blocklists, allowing senders to promptly address listing issues.
  • Seed List Testing: Deliverability APIs facilitate seed list testing to evaluate inbox placement rates across various ISPs.
  • Automated FBL Processing: Some APIs automate feedback loop processing, streamlining complaint management and subscriber removal.

Key considerations

  • Real-time Alerts: Ensure the API provides timely alerts for blocklist appearances to enable quick action.
  • Seed List Coverage: Check the API's seed list coverage to ensure it includes a representative sample of ISPs relevant to your audience.
  • FBL Integration: Verify seamless integration of the API with your existing email infrastructure for efficient FBL processing.
Expert view

Expert from Spam Resource explains that one key use of deliverability APIs is to monitor blocklists in real time. This allows senders to quickly identify if their IPs or domains have been listed and take corrective action.

February 2025 - Spam Resource
Expert view

Expert from Spam Resource explains that some deliverability APIs offer automated feedback loop (FBL) processing. This helps senders to efficiently manage complaints and remove subscribers who mark emails as spam.

September 2022 - Spam Resource
Expert view

Expert from Spam Resource shares that deliverability APIs can be utilized for seed list testing. By sending emails to a network of seed addresses and analyzing the results, senders can gain insights into inbox placement rates at different ISPs.

March 2022 - Spam Resource

What the documentation says
5Technical articles

Various email service providers and tools offer APIs to enhance email deliverability. AWS SES provides authentication options and feedback loops. Google's Gmail API allows programmatic sending and deliverability reporting. Microsoft Graph API enables sending via Outlook and deliverability tracking in Microsoft 365. MailerQ offers an MTA with API for managing queues and optimizing sending strategies. Mailosaur's API focuses on automated email testing and deliverability monitoring.

Key findings

  • Platform Integration: APIs often integrate deeply with existing email platforms (AWS, Google, Microsoft) for seamless deliverability management.
  • Authentication: Support for authentication protocols (SPF, DKIM, DMARC) is common to improve sending reputation.
  • Monitoring Tools: Comprehensive deliverability reports and monitoring tools are frequently included.
  • Testing APIs: APIs exist specifically for automated email testing to ensure proper formatting and delivery.
  • Queue Management: MTAs offer APIs for managing email queues and optimizing sending strategies.

Key considerations

  • Ecosystem Alignment: Choose an API that aligns with your existing email infrastructure and ecosystem.
  • Authentication Setup: Properly configure authentication protocols to maximize deliverability benefits.
  • Reporting Depth: Evaluate the level of detail provided in deliverability reports to identify and address issues.
  • Testing Capabilities: Consider the testing capabilities offered by the API to ensure email quality.
  • Customization: Determine the level of customization and control over sending strategies offered by the API.
Technical article

Documentation from Mailosaur details their Email Testing API is designed for automated email testing and deliverability monitoring, helping developers ensure their emails are properly formatted and delivered.

January 2024 - Mailosaur
Technical article

Documentation from Google describes the Gmail API that enables users to send emails programmatically, manage drafts, and access detailed deliverability reports within the Gmail ecosystem.

December 2024 - Google Developers
Technical article

Documentation from Microsoft details the Graph API, which allows users to send emails through Outlook, manage email settings, and track deliverability statistics within the Microsoft 365 environment.

August 2023 - Microsoft Graph Documentation
Technical article

Documentation from AWS explains the SES API allows users to send emails and monitor deliverability metrics. It offers configuration options for authentication (SPF, DKIM, DMARC) and feedback loops to improve sending reputation.

September 2021 - AWS Documentation
Technical article

Documentation from MailerQ details their high-performance Message Transfer Agent (MTA) that offers an API for managing email queues, monitoring deliverability, and optimizing email sending strategies.

June 2023 - MailerQ Documentation