With the right email API, you can easily send and receive emails in your application, allowing you to focus on building critical, differentiating communications features that drive in-app engagement and maximize retention.
This post will review some of the best email APIs on the market, cover the most important features, and discuss different pricing models and how they work so you can make an informed decision about the right one for you.
What are email APIs?
Email APIs (Application Programming Interfaces for emails) are a set of protocols and tools that allow developers to integrate email functionality into their applications. With an email API, users can send and receive emails, retrieve email messages, manage email addresses, and perform other email-related tasks all within an organization’s platform.
Using incoming emails to trigger certain actions (e.g., creating a task in a project management app when an email is received)
Retrieving information about emails, such as subject lines and sender addresses
Track contact lists
Report on key metrics like open rate and clickthrough rate (CTR)
There are several categories of email APIs available, including web APIs, SMTP (Simple Mail Transfer Protocol) APIs, POP (Post Office Protocol) APIs, and IMAP (Internet Message Access Protocol) APIs.
Each of these protocols has its own set of features and capabilities, and developers can choose the one that best fits their needs. Using an API means developers can connect their apps to email providers in minutes – without any coding required.
SMTP vs. web API
SMTP APIs and web APIs are application programming interfaces that allow different software systems to communicate with each other.
SMTP APIs allow you to interact with email servers and services programmatically and can be used to send automated emails, receive and parse emails, and manage email lists.
Web APIs enable communication between various applications, services, and systems. They can be used to retrieve data, perform tasks, and interact with other systems in various ways. These APIs are typically implemented using HTTP and JSON and are often used to build integrations between different software systems or to expose data or functionality to developers.
Types of email APIs
Transactional vs. contextual
Transactional APIs are best for businesses that need to send out a massive volume of emails in quick succession that require very little customization. These types of APIs are best suited for automated marketing updates, promotional offers, and transactional notifications.
Contextual APIs are best for businesses that need to send and receive emails in a conversational context. These APIs facilitate personalized interactions such as sales outreach, customer service inquiries, or tailored newsletters. Conversational APIs allow users to send messages directly from their own address, customize each message with HTML and images, as well as use analytics tracking to measure engagement rates – all while ensuring high deliverability rates.
Sending vs. receiving
Email Sending APIs allow you to automate email messages and tailor them according to your business’s needs. Both transactional and contextual APIs support sending capabilities.
Receiving APIs allow organizations to receive emails from customers or other third parties. You can connect your existing email service with an external provider to receive more emails at once without having to manage each message manually.
Transactional APIs can offer support for receiving email, but if you’re sending and receiving messages within the context of a conversation, contextual APIs provide a far better end-user experience.
Benefits of using email APIs
Some of the key benefits of using email APIs include:
Email deliverability
Businesses and organizations can increase the deliverability of their emails by ensuring that they follow best practices for sending emails. This includes obtaining permission from recipients before sending emails, using a reputable and properly configured email server, and following guidelines for spam filtering.
With improved email deliverability, you can send directly from your users’ inboxes and avoid proxy sends.
Personalization
APIs allow companies to incorporate personalization into email campaigns by allowing them to access and use data about the recipient, such as their name, location, or past interactions with the business. This data can be used to create personalized email subject lines, content, and calls to action tailored to the individual recipient.
Analytics
An email API can provide a range of analytics and tracking capabilities, such as real-time email tracking, open and click-through rates, and conversion tracking. This helps businesses and organizations assess the effectiveness of their email campaigns.
Seamless integrations
Email APIs allow developers to integrate email functionality into their applications or websites easily. For example, eCommerce websites can use native email integrations to send confirmation emails or personalized product recommendations to customers, while CRM systems can also use email APIs to send automated outbound cadences and follow-ups.
Cost & time savings
By integrating their existing email service with third-party services, businesses can save money and time by streamlining the process of sending emails from their app. Email APIs abstract away the burden of building email features on your own, saving thousands of developer hours and allowing you to launch new capabilities in weeks or months.
Plus, these APIs drastically reduce the ongoing maintenance burden, bug resolution, and accounting for unforeseeable customer edge cases that every integration requires.
In short, APIs let you reinvest your team’s time and energy into delivering differentiating features that drive engagement and boost retention.
Best email APIs
As businesses continue to rely on email for communication and customer service, having an effective way to receive and send emails is essential. This is where the best email APIs come in.
Let us explore 11 of the best options available on the market and discuss their key features, capabilities, and pricing.
Nylas
How it works: Nylas is the best email API in 2023 because it is the fastest and easiest way to connect to your users’ inboxes and stand up engaging email capabilities. The Nylas platform enables businesses to save thousands of developer hours and build powerful email, calendar, and contacts features so you can focus on your customers, not infrastructure.
Additionally, the Nylas Email API provides companies with industry-leading 99.9% deliverability, ensuring your users’ messages land in the inbox, not SPAM. Nylas is also well known for its highly secure, scalable architecture and highly responsive customer support team.
Key features:
Universal API that connects to 100% of email service providers
Stand-up bi-directional sync and full Create, Read, Update, Delete (CRUD) capabilities
Access to powerful unstructured email data
Send directly from your users’ inboxes vs proxy sends, with Nylas’ industry-leading 99.6% deliverability
Message tracking and analytics
Smart compose and intelligent endpoints
Dedicated and responsive customer success team
Pricing:
Nylas offers a full-service API platform including an email API, calendar API, and contact API. Pricing plans vary by the number of connected accounts (end users).
To choose the best plan for your business, talk to an expert to get a quote today.
SMTP.com
How it works: SMTP.com is a transactional API solution that enables IT professionals and developers to integrate email into their web applications. Businesses can tailor their emails according to the recipient’s preferences, such as geographic location, device type, etc. Additionally, users can track their email campaigns in real time with analytics.
How it works: Sendgrid provides users with a transactional email API for managing their emails, enabling businesses to reach a wider audience reach. Sendgrid’s analytics allows users to monitor email campaigns and measure their success. The platform also offers tracking features, such as open rates, click-through rates, and more.
ESSENTIALS (40K, 100K Packages): $14.95 to $29.95/month
PRO (100K, 300K, 700K, 1.5M, 2.5M Packages): $89.95 to $949.95/month
Premier Plan: Contact SendGrid for a quote
Amazon SES
How it works: Amazon SES is a transactional email service provider that can integrate into email-sending applications. Amazon SES offers analytics to measure deliverability rates, open rates, click-through rates, and more. Amazon SES includes security features against attackers and phishing scams.
How it works: Mailgun is a cloud-based email service that allows users to send and track transactional emails. The platform enables businesses to customize emails according to the recipient’s preferences, such as language or device type.
Mailgun’s analytics dashboard provides information about the performance of emails, including open rates, click-through rates, and more. Users can also use Mailgun’s drag-and-drop editor to create HTML emails.
How it works: Postmark is an email delivery service designed to allow developers to send marketing and transactional email with high deliverability.
Postmark also provides users with various API-based tools for monitoring deliverability and preventing bounces. In addition, the platform provides businesses with templates for password resets, welcome emails, receipts, invoices, user invitations, and more.
Key features:
Spam Blocker
Email Monitoring
Data Recovery
Response Management
Signature Management
Pricing:
Postmark offers eight pricing levels:
10,000 emails: $10/month
50,000 emails: $50/month
125,000 emails: $100/month
300,000 emails: $200/month
700,000 emails: $400/month
1.5M emails: $700/month
3M emails: $900/month
5M emails: $1,200/month
7. SparkPost
How it works: Sparkpost is an email delivery platform that helps businesses predict and monitor ISP responses, email bounce rates, and spam traps in real time. The inbox tracker enables marketers to create and send emails using subject line prediction, blacklist monitoring, and brand impersonation protection methods.
Additionally, users can configure two-factor authentication and SSL encryption to provide a secure user experience. SparkPost also comes with an API that allows businesses to integrate the system with other third-party solutions.
Key features:
Single email verification
Spam detection
Syntax check
Real-time alerts
Webhooks integration
Pricing:
Sparkpost has four pricing models:
Starter: $20/month
Premier 100K messages: $75/month
Premier 250K messages: $170/month
Premier 1M messages: $525/month
8. Mailchimp
How it works: Mailchimp is a web-based marketing automation service that allows users to share newsletters on social networks and track customer engagements. Mailchimp offers a marketing API, transactional emails, and an API-first commerce stack. Organizations can manage audiences, integrate data, and send timely email campaigns.
Key features:
Automated Scheduling
Email Tracking
Collaboration Tools
Social Marketing
Click Tracking
Pricing:
Mailchimp offers four pricing levels:
Free: $0
Essentials: $13/month
Standard: $20/month
Premium: $350/month
9. Mailmodo
How it works: Mailmodo is an API that helps companies design, test, and deliver emails on different devices and browsers. It provides a platform to create professional email campaigns from scratch or existing templates.
Mailmodo is a no-code ESP solution that has all the features of a traditional ESP, like email analytics, sending transactional campaigns, email automation and drip emails with customer journeys, drag-and-drop email editor, useful integrations with CRMs, connectors, marketing tools, and more.
Looking for a specific email API? Here are some of the best email API options for sending, receiving, and more.
Best Email API for Google integration
Nylas
SendGrid
Postmark
Best Email API service for developers
Nylas
SMTP.com
Email Engine
Best free email API
The following APIs offer free plans:
Mailgun
Sendinblue
Mailchimp
Best REST Email API to send emails
Nylas
Mailchimp
Amazon SES
Best receiving email API
Nylas
Mailmodo
SparkPost
Nylas allows organizations to sync, send, and receive emails, while many other options only provide sending capabilities.
Choose the best email API
There are many excellent email APIs on the market that can help businesses and organizations to improve their email communications and marketing efforts.
With its universal connectivity, bi-directional sync, and unparalleled reliability, Nylas is a top choice for businesses and developers looking to stand up engaging, embedded email capabilities in their applications.
Whether you need to send automated emails, track real-time performance, or personalize your messaging, Nylas has the tools and capabilities you need to succeed.
Email and Contacts API 
Calendar API & Scheduler 
Notetaker API 
Agent Accounts 
Sales & CRM 
Recruiting & ATS 
Healthcare
Financial
Legal
Real Estate
Education
Field Services
Docs
SDKs
Tutorials
API status
Changelog
Support
