Software Alternatives & Startups

Postmark VS Ably

Compare Postmark VS Ably and see what are their differences

Postmark

Postmark is the easiest and most reliable way to be sure your important transactional emails get to the inbox. Simply & reliably parse recieved email to JSON for your webapp.

Rating
0 reviews
Pricing
Open source
Ably

The realtime platform that just works. We power more WebSocket connections than any other pub/sub platform, serving over 2 billion devices monthly.

Rating
0 reviews
Pricing
Freemium Free trial
Note: These products don't have any matching categories. If you think this is a mistake, please edit the details of one of the products and suggest appropriate categories.

Which is more popular?

Based on our record, Postmark should be more popular than Ably. It has been mentioned 58 times since March 2021.

social mentions
58 vs 26
Email Marketing popularity
100% vs 0%
alternatives listed
240+ vs 139

Base details

Website, pricing, platforms and company facts side by side.

Postmark
Ably
Website postmarkapp.com ably.com
Pricing
Open source Official pricing
Freemium Free trial Official pricing
Company Startup from the United States Startup from the United Kingdom · 50 - 99 employees · 2016
Listed in

About Postmark and Ably

In their own words, as submitted to SaaSHub.

Postmark
Ably

No description of Postmark yet.

We help teams deliver resilient AI UX and high-performance live experiences that stay fast and in sync worldwide. We provide the global realtime layer for AI agents, chat, notifications, live dashboards, and collaboration - engineered to handle peak demand without self-managed infrastructure....

Read more about Ably

Features and specs

What each product offers, as listed by its team.

Postmark 7 features
Ably 8 features
  • High Delivery Rates
    Postmark is known for its high email delivery rates, ensuring that transactional emails reach inboxes promptly.
  • Fast Sending Speed
    Emails through Postmark are processed and sent very quickly, which is crucial for transactional emails requiring immediate delivery.
  • User-Friendly Interface
    The platform has an intuitive and easy-to-navigate interface, making it accessible for users of varying technical skills.
  • Detailed Analytics
    Postmark provides comprehensive analytics, including open rates, click rates, and delivery logs, enabling detailed tracking of email performance.
  • Reliable API
    Postmark offers a highly reliable and well-documented API, facilitating seamless integration with various applications.
  • Top-Notch Customer Support
    The service is praised for its responsive and knowledgeable customer support team, available to assist with any issues.
  • Emphasis on Security
    Postmark prioritizes email security with features like two-factor authentication and SSL encryption.

Possible disadvantages

  • Cost
    Postmark's pricing can be relatively high compared to some other email service providers, particularly for larger email volumes.
  • Lack of Marketing Email Features
    Postmark is primarily designed for transactional emails and lacks many advanced features needed for marketing emails, such as list segmentation and complex automation workflows.
  • Rate Limits
    Postmark imposes rate limits on sending emails, which might be a constraint for businesses with very high or bursty email volumes.
  • Limited Template Customization
    While Postmark allows for the use of email templates, the customization options are more limited compared to specialized email design tools.
  • Geographical Limits
    Postmark's server locations are primarily based in the U.S., which may affect email delivery speeds in other regions.
  • Lack of SMS Integration
    Postmark does not offer SMS sending capabilities, which may be a drawback for businesses looking to consolidate their communication channels.
  • Scalability
    Ably is designed to handle a massive number of concurrent connections and messages, making it scalable for both small and large applications.
  • Real-time Messaging
    Ably provides robust real-time messaging capabilities with low latency, supporting use-cases like live chat, gaming, and real-time data streaming.
  • Global Presence
    Ably has a globally distributed network, ensuring low latency and high availability for users around the world.
  • Advanced Features
    It offers advanced features such as message history, presence, and push notifications, which can enhance the functionality of real-time applications.
  • Security
    Ably includes built-in security features such as TLS encryption, token-based authentication, and private channels to ensure secure communication.
  • Extensive Documentation
    The service provides extensive and well-organized documentation, making it easier for developers to integrate and utilize its features.
  • SDKs and Libraries
    Ably offers a wide range of SDKs and libraries for different programming languages and platforms, easing the development process.
  • Reliable Delivery
    It ensures reliable message delivery with features like message queuing and message de-duplication.

Possible disadvantages

  • Complexity
    Due to its wide range of advanced features, the initial learning curve can be steep for new users.
  • Cost
    For large-scale applications or extensive use of advanced features, the costs can add up, making it potentially expensive.
  • Vendor Lock-in
    Relying heavily on Ably’s platform-specific features may result in vendor lock-in, making it challenging to switch to other services in the future.
  • Dependence on Internet Connection
    As a cloud-based service, Ably’s performance is highly dependent on the quality and reliability of the internet connection.
  • Third-party Integration
    While Ably offers various integration options, integrating certain third-party services may require additional custom development or may not be as seamless.

Analysis

An editorial look at what each product does well and who it suits.

Postmark
Ably

Overall verdict

  • Yes, Postmark is considered a good option for those needing a reliable and efficient transactional email service. It stands out due to its focus on speed, deliverability, and ease of use for both developers and businesses.

Why this product is good

  • Postmark is praised for its reliable email delivery service, which is specifically designed for transactional emails. It offers fast delivery times, extensive real-time tracking, and detailed analytics. Additionally, Postmark provides a user-friendly API and robust documentation, making it easy for developers to integrate and maintain. The service is known for its strong focus on sending emails quickly and efficiently, with a low probability of ending up in spam folders.

Recommended for

  • Businesses needing efficient and reliable transactional email delivery.
  • Developers looking for easy API integration and robust documentation.
  • Organizations requiring real-time email tracking and detailed analytics.
  • Companies prioritizing quick email deliverability and avoiding spam filters.

Overall verdict

  • Ably is a reliable and efficient real-time messaging platform, well-suited for applications requiring high performance and scalability. It is generally well-regarded within the developer community for its ease of use and robust feature set.

Why this product is good

  • Features
    Ably provides a comprehensive suite of features such as pub/sub messaging, presence, and history.
  • Security
    It implements robust security practices including TLS encryption, token-based authentication, and private channels.
  • Integration
    Supports numerous protocols and provides SDKs for various programming languages, making it easy to integrate with different systems.
  • Reliability
    Ably offers high availability and low latency, ensuring messages are delivered in real-time.
  • Scalability
    The platform can handle millions of active connections and is designed for horizontal scaling.

Recommended for

  • developers building real-time applications like chat apps, dashboards, or multiplayer games
  • businesses in need of a scalable solution for live updates and notifications
  • teams looking for a platform with strong security and compliance credentials
  • organizations requiring integration with existing development workflows and tools

Videos

Walkthroughs and reviews on video.

Postmark 1 video + Add
Ably 3 videos + Add

Using Postmark to send email from Darkroom Booth

How to build a collaborative environment around your product

More videos

  • - How to build an avatar stack with Ably Spaces
  • - Ably 101: Serverless WebSockets at scale

Category popularity

How often each product is chosen within a category, 0–100% relative to the other.

Score bands 0–20 21–40 41–50 51–60 61–100
Postmark
Ably
100% 100%
0% 0%
0% 0%
100% 100%
100% 100%
0% 0%
0% 0%
100% 100%

User comments

Share your experience with using Postmark and Ably. For example, how are they different and which one is better?

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Reviews and articles

External articles and on-site reviews we used to compare the two products.

Postmark no reviews yet
Ably no reviews yet

We have no reviews of Ably yet. Be the first one to post

Social recommendations and mentions

Recommendations tracked on public social media and blogs since March 2021.

Postmark 58 mentions
Ably 26 mentions
  • 7 Best Email APIs for Developers in 2026 (Compared)
    Postmark has been doing one thing for over a decade: getting transactional email into inboxes fast. It separates transactional and broadcast traffic into different "message streams" so marketing sends don't damage your password-reset... - Source: dev.to / 12 days ago
  • 7 SMTP APIs Worth Knowing in 2026, and Where I'd Start
    Postmark has been doing exactly one thing since 2010: transactional email, done carefully. It enforces a hard separation between transactional and bulk/marketing sending streams (you can't mix them on the same account), which is exactly... - Source: dev.to / about 1 month ago
  • Congrats to the Winners of Postmark Challenge: Inbox Innovators!
    We want to shout out Postmark for sponsoring this challenge. Postmark's developer-focused API and reliable inbound email parsing made these innovative projects possible, allowing the community to focus on creativity rather than email... - Source: dev.to / over 1 year ago

View more

  • AWS us-east-1 outage: How Ably’s multi-region architecture held up
    During this week’s AWS us-east-1 outage, Ably maintained full service continuity with no customer impact. This was our multi-region architecture working exactly as designed; error rates were negligibly low and unchanged throughout. Any... - Source: dev.to / 12 months ago
  • Real-Time Sync Alternatives: Vaultrice vs. localStorage, DIY, Firebase, Pusher
    Services like Pusher and Ably are experts in real-time messaging. They provide robust APIs for pub/sub channels, allowing you to broadcast events to clients reliably. - Source: dev.to / about 1 year ago
  • CometChat Alternatives – Comparing the Top 10 Competitors
    Ably is a real-time infrastructure platform that focuses on delivering low-latency, reliable messaging across global distributed systems. It's designed for developers building event-driven applications, including chat, but also supports... - Source: dev.to / over 1 year ago

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Alternatives to Postmark and Ably

When comparing Postmark and Ably, you can also consider the following products.

  • Mailgun

    A set of powerful APIs that enable you to send, receive and track email from your app effortlessly whether you use Python, Ruby, PHP, C#, Node.js or Java.

    Compare Mailgun to Postmark or Ably:

  • Pusher

    Pusher is a hosted API for quickly, easily and securely adding scalable realtime functionality via WebSockets to web and mobile apps.

    Compare Pusher to Postmark or Ably:

  • Resend

    Email for developers

    Compare Resend to Postmark or Ably:

  • Socket.io

    Realtime application framework (Node.JS server)

    Compare Socket.io to Postmark or Ably:

  • Brevo

    Innovative online Email Marketing solution to manage your contacts, create & send your newsletters and track your results. More than 80 000 clients. Best prices and attractive features.

    Compare Brevo to Postmark or Ably:

  • PubNub

    PubNub is a real-time messaging system for web and mobile apps that can handle API for all platforms and push messages to any device anywhere in the world in a fraction of a second without having to worry about proxies, firewalls or mobile drop-offs.

    Compare PubNub to Postmark or Ably: