The Most Popular PubNub Alternatives: A Comprehensive Guide

Looking for more flexible, cost-effective, or feature-rich alternatives to Pubnub? This guide will assist you by providing a detailed comparison of top Pubnub competitors to help you make an informed decision.

Aarathy Sundaresan • Oct 27, 2023

For businesses relying on real-time chat to enhance user engagement and retention, selecting the ideal chat sdk platform is a critical decision. Whilst PubNub has been a well-known choice, there are also other viable alternatives.

In this blog, we will explore some of the top alternatives to PubNub. But first, let's take a closer look at how PubNub works and some of the main reasons why businesses look for alternatives to PubNub.

PubNub : A Quick Overview

PubNub is a real-time infrastructure-as-a-service (IaaS) company offering a cloud-based platform enabling developers to build, manage, and scale real-time applications. Its key offering is a real-time publish/subscribe (pub/sub) messaging API.

In the pub/sub model, messages are dispatched to specific 'channels' or 'topics', and then received by subscribers to these channels. This model allows for scalability and network dynamics, with publishers (senders of messages) and subscribers (receivers), functioning independently. This means that a new chat message or a live game score update can be pushed out to interested users in real-time at scale.

However, the pub/sub approach democratises the construction of real-time messaging systems, leading to a significant amount of custom development. As a result, businesses may find themselves building some chat features and the chat UI from scratch - a potentially time-consuming and complex process. In the following sections, we'll delve deeper into the challenges faced when using PubNub and other pub/sub based solutions for building real-time messaging applications.

PubNub's Perfomance Limitations

  1. 01.

    Uneven message ordering

    PubNub does not guarantee that messages will be delivered to subscribers in the exact same order in which they were published. While it provides mechanisms for maintaining order, developers need to implement additional logic to ensure message sequencing, which always proved to be complex.

  2. 02.

    Lack of a reliable message delivery method

    Pubnub has a message queue size of 100. If a user experiences a temporary loss of connectivity and published messages exceeds this limit, older messages may be discarded and remain undelivered upon the user's subsequent reconnection.

  3. 03.

    PubNub's Pub/Sub model typically does not persist messages

     If a subscriber is offline or not subscribed to a channel when a message is published, they may miss that message. Developers may need to implement additional systems for message persistence and offline message delivery.

  4. 04.

    No in-built user presence indicators

    Unlike other real-time messaging platforms like CometChat that offer built-in user presence features, PubNub does not have a native mechanism for automatically detecting user's online or offline status. Instead, developers must design, implement, and maintain their own system for this purpose. This could consume developer’s time and efforts and could also add complexity.

PubNub's Security Limitations

  1. 01.

    Lack of Authentication and Security: 

    PubNub offers no inbuilt authentication or security, potentially making it unsuitable for applications requiring strict access control, and forcing developers to create their own authentication and authorization layers which would incur significant dev time and cost.

  2. 02.

    Potential for Unwanted Messages: 

    In an open pub/sub model, there is a risk of receiving unwanted or spam messages. Without proper controls, channels can be prone to unsolicited messages, which can affect user experience and necessitate filtering mechanisms.

  3. 03.

    Absence of robust compliance standards

    PubNub's pub/sub model lacks inbuilt security and privacy measures, burdening developers with the task of ensuring regulatory compliance. In sectors like healthcare and finance, where sensitive data is handled, privacy and compliance are critical. This can be complex, time-consuming, and non-compliance carries the risk of heavy fines and reputational damage.

  4. 04.

    Channel naming conflicts

    Since channel names are typically chosen by users or developers, there's a possibility of naming conflicts or channels with similar names. This can lead to confusion and potential issues in message deliver

PubNub's Pricing Limitations

Navigating PubNub's pricing can be a tricky task due to its multiple variables and complex structure. They offer an array of plans including a Free plan for up to 200 Monthly Active Users (MAUs), a Starter plan ($49/month for up to 1000 MAUs), and a customizable Pro plan. However, each plan comes with stringent transaction limits, turning the cost-effective plans into a potential financial black hole as your scale increases.

Adding to the complexity is PubNub's decision to charge separately for customer support services, which is a departure from the norm set by other vendors, such as CometChat, who bundle these in. PubNub offers three tiers of support—Standard, Gold, and Platinum—each providing an escalating degree of service at a corresponding cost. To avail comprehensive services such as Slack support, phone support, customers need to invest in the Platinum plan which comes with a hefty $1500 per month price tag.

Lastly, PubNub’s overage charges can quickly add up and become costly at scale, leading to unpredictable and potentially inflated monthly bills, which is particularly concerning for growing businesses.

PubNub's extendability limitations

While PubNub has its strengths, its lack of extendability can become a hurdle for businesses aiming to offer comprehensive real-time engagement solutions.

Firstly, a glaring omission in PubNub's offerings is the absence of a native voice or video solution. This means businesses looking to incorporate real-time voice or video chat into their applications must rely on integrating third-party solutions, which can be a complex and time-consuming task.

Secondly, PubNub's focus is not on providing a deep, holistic solution. This can hinder businesses trying to weave chat experiences seamlessly into their core product offerings. The lack of depth in the solution can result in a disjointed user experience and increased development efforts to bridge any gaps.

Lastly, PubNub's webhooks leave much to be desired. With only basic offerings such as presence webhooks, businesses may find it challenging to trigger core product actions based on chat events. This primitive approach to webhooks can limit the ways in which real-time chat can be used to enhance interactivity and user engagement within an application.

6 Popular alternatives to PubNub


CometChat is a robust chat API & in-app messaging SDK provider that enables businesses to add chat and video, voice calling features into their mobile apps and websites.

CometChat offers a range of solutions that serve various use cases such as one-on-one chat, group conversations, voice & video calling, and more.

It can be easily incorporated into different types of applications, including team collaboration tools, online marketplaces, dating apps, healthcare apps, e-learning platforms, gaming apps, and more.

Key features of CometChat include:

  • Highly Customizable: Our chat sdks and pre-buit UI components can be tailored to suit the specific needs of different businesses.

  • Rich Engagement Features: Features like message reactions, typing indicators, presence indicators, read receipts, file sharing, and more.

  • Advanced moderation tools: CometChat provides advanced moderation tools like data masking, content moderation, user banning to ensure user safety and compliance with platform rules.

  • Support for Different Platforms: CometChat supports different platforms, including Android, iOS, and the web.

  • Easy Integration: CometChat offers several options for integration, including UI Kits, SDKs, and Widgets, allowing businesses to choose the best fit for their needs.

  • Scalability: CometChat is designed to scale with businesses as they grow, ensuring that the chat experience remains smooth, even with an increase in users.

  • Innovative pricing: In addition to the standard MAU based pricing, we also provide usage-based pricing for enterprise businesses.

CometChat is trusted by thousands of customers globally, from small startups to big enterprises, due to its ease of use, robust features, and reliability.

See how Boatyard overcame their challenges with maintaining an in-house real time chat system by using CometChat

Learn how leveraged CometChat's Presence Webhook to refine their real-time matchmaking algorithm

Find out how NoBrokerHood overcame their user adoption challenge and enhanced community interaction by adding real time chat


Sendbird is a technology company that provides chat API and messaging SDKs. It enables developers to add real-time chat, voice, and video functionalities to their platforms, facilitating user-to-user, group, and channel communication.

Sendbird's solutions serve various use cases across several industries, including gaming, online communities, marketplaces, on-demand services, live-video streaming, and more.


  • Multi-platform support

  • Real-time messaging and calling

  • Comprehensive documentation


  • Sendbird's pricing is not scale friendly and they also charge a heft overage fee.

  • Primitive UI kits that lacks business logic.

  • Extensive development time

Here is a more detailed article with a complete list of Sendbird's limitations and how it compares with its' peers.


StreamChat is a service provided by Stream, a technology company that offers scalable APIs for building social networks, activity feeds, and chat applications.

StreamChat provides API and SDKs that developers can use to add real-time messaging capabilities to their mobile apps or websites. It supports one-to-one messaging, group chat, and large channel messaging.

It includes features such as automated moderation to safeguard against inappropriate content, a profanity filter, and message flagging. It also supports rich messages allowing for inline images and attachments, emojis, markdown, URL enrichment, and more.

However, it's important to note that the platform's customization options, while available, may not be as extensive as some competitors, potentially limiting highly tailored user interfaces.

Additionally, while StreamChat offers solid technical support, the responsiveness and depth of support may vary depending on the subscription tier.


Ably is real-time data delivery platform and messaging service, equipped with a suite of APIs and developer tools.

Like Pubnub, Ably also employs a publish-subscribe (pub/sub) messaging model, Ably enables efficient dissemination of data by allowing it to be published to specific channels, ensuring subscribers receive timely updates.

This adaptability positions Ably as a valuable asset across various applications, ranging from messaging apps and collaborative tools to online gaming, live streaming.

However, it's essential to take into account Ably's usage-based pricing model, where costs can escalate with increased application traffic and usage. Managing high data transfer or message volume can potentially result in substantial expenses, necessitating a comprehensive understanding of Ably's pricing structure and its implications for your budget.

Depending on the nature of the transmitted data, developers may also need to implement additional security measures to ensure data privacy and regulatory compliance, such as adhering to GDPR or HIPAA standards.

Socket.IO is a JavaScript library that enables real-time, bidirectional, and event-based communication between web clients and servers.

The main capabilities provided by Socket.IO include:

Real-Time Analytics: Push data to clients that gets represented as real-time counters, charts, or logs.

Binary Streaming: Starting in 1.0, it's possible to send any blob back and forth, including images, audio files, and video files.

Instant Messaging and Chat: Socket.IO's "room" and "namespace" concepts can be used to divide chat users into different rooms or functions.

Document Collaboration: Many users can interact with the same document and see changes in real-time.

Its event-driven complexity can make development and debugging more intricate, and its resource demands might not align with lightweight or resource-constrained projects.

Moreover,'s compatibility can be less certain in older browsers and unconventional network setups, and ensuring robust security measures is imperative in real-time applications.

Scalability challenges may arise with large deployments, and staying abreast of backward compatibility when updating the library can pose additional hurdles. While offers powerful real-time capabilities, developers should weigh these potential downsides against their project requirements and undertake thorough planning and maintenance to harness its benefits effectively.

Firebase by Google

Firebase by Google offers robust real-time communication capabilities through its Firestore and Realtime Database services. Firestore provides a scalable and flexible NoSQL database with real-time data synchronization, allowing developers to build collaborative and responsive applications such as chat apps, live dashboards, and multiplayer games. Firebase's Realtime Database, though older, similarly enables real-time data updates and synchronization.

Advantages include seamless integration with other Firebase services, straightforward setup, and strong offline support. However, potential disadvantages include limited querying capabilities, scalability challenges with high write loads, and the need for careful data structuring to optimize performance. Nonetheless, Firebase remains a popular choice for real-time communication in web and mobile applications due to its ease of use and strong ecosystem support.

Aarathy Sundaresan

Content Marketer , CometChat

Aarathy is a B2B SaaS Content Marketer at CometChat, excited about the convergence of technology and writing. Aarathy is eager to explore and harness the power of tech-driven storytelling to create compelling narratives that captivate readers. Outside of her professional pursuits, she enjoys the art of dance, finding joy and personal fulfillment.