Comparing chat solutions

PubNub vs. Sendbird: Discover the right choice for your use case

A head-to-head comparison between Sendbird and PubNub for live chat use cases. Learn about their features, pros and cons, similarities, and differences.

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What is Sendbird?

Sendbird is a Platform-as-a-Service (PaaS) that provides APIs and SDKs to enable messaging, chat, and voice and video calling in web and mobile apps. 


The Sendbird Chat product is the primary Sendbird offering for building chat experiences. It’s an API-based service that gives developers tools to add realtime, 1-on-1, and group chat functionality to their apps.

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Pros and cons of Sendbird Chat

What are the key pros and cons of using Sendbird Chat?

Sendbird Chat advantages

  • Feature-rich chat API, with diverse capabilities, including voice and video support, message and user moderation, push notifications, reactions, mentions, typing indicators, user presence, and read receipts. 

  • Ready-made UI components for iOS, Android, React, and React Native, which helps save time versus building your own UI chat components. 

  • Managed infrastructure layer that’s supposedly able to scale to 1 million+ concurrent connections per client app.

  • Compliance with security standards such as SOC 2, ISO 27001, HIPAA/HITECH, and GDPR.

Sendbird Chat limitations

  • Chat often goes hand-in-hand with other realtime use cases, such as multiplayer collaboration (think of Figma-like products, where you can edit your design collaboratively, and chat with other users, all in realtime). However, Sendbird is very much a chat-centric solution; if you’re looking to build other realtime experiences alongside chat, Sendbird can’t help; you will have to use different technologies, which brings additional complexity and increased costs to your project. 

  • Sendbird Chat allows you to have a fixed number of monthly active chat users (MAUs) and concurrent (peak) connections. If you exceed the number of allowed MAUs & peak connections, you will be charged overages. However, there’s no transparency about exactly how much you will be charged. This is perhaps not the “friendliest” pricing model, especially if you’re dealing with a high number of users and traffic spikes.  

  • While Sendbird infrastructure is deployed across 8 datacenters, you are required to choose a single region (datacenter) for an app to reside in. All chat traffic must therefore be routed through a single datacenter, regardless of a user’s location. This has negative implications on performance (increased latency), reliability, and availability. It’s probably one of the reasons why Sendbird provides a 99.9% uptime SLA by default. This SLA may not be reliable enough for critical use cases, such as healthcare chat. 

  • Sendbird Chat offers a limited number of client SDKs (7 in total), with no support for languages like Java, Go, PHP, Python, or Ruby. It’s also worth mentioning that Sendbird has very limited options when it comes to integrations. It essentially only allows you to configure webhooks, but it offers no pre-built integrations with other components, like databases, event streaming platforms (e.g., Kafka), or serverless platforms.

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What is PubNub?

The PubNub Data Stream Network (PubNub for short) is a PaaS that allows developers to build and deliver realtime interactivity in web and mobile apps, for use cases such as live chat, multi-user collaboration, and IoT device control. PubNub provides pub/sub APIs, realtime SDKs, and a globally-distributed network of datacenters.


Specifically for chat use cases, PubNub offers Chat SDKs and Chat UI Components, which are built on top of the core PubNub platform. 

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Pros and cons of PubNub Chat

What are the key pros and cons of using PubNub Chat?

PubNub Chat advantages

  • Provides globally-distributed infrastructure spanning 15 datacenters, with data replication in multiple regions to protect against single points of failure.

  • APIs and SDKs with diverse capabilities for building chat experiences with features like typing indicators, read receipts, reactions, mentions, and mute/ban users.

  • 99.999% uptime SLA (exclusively for customers with the Pro package).

  • Compliance with GDPR, SOC 2, CCPA, and HIPAA (the latter is only available for Pro customers). 

PubNub Chat limitations

  • PubNub does not guarantee that messages reach subscribers in the exact same order in which they are published. Message delivery is not guaranteed either - there’s a queue limit of 100 messages. If more than 100 messages are published while a chat user temporarily loses connectivity (e.g., driving through a tunnel), older messages will get discarded, and will never be delivered to the user once they reconnect. 

  • HTTP long polling is used for realtime communication between PubNub servers and chat clients. Note that long polling is an inferior option to other realtime transports. For example, compared to WebSockets, long polling is more resource intensive, and has higher latencies.  

  • There’s a lack of transparency around pricing. There’s no way to calculate how much you would be charged per month, as there is not enough publically available pricing information, nor are there any pricing examples/estimates. You are forced to contact sales to find out more.

  • Compared to other chat solutions, PubNub Chat offers a limited number of client SDKs (6), with no support for languages and platforms like Java, Go, PHP, or Python. Similarly, PubNub Chat components are available exclusively for React and React Native. 

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PubNub Chat vs Sendbird Chat: feature comparison

The purpose of this comparison is to help you make a more informed decision when it comes to choosing the best chat solution for your project. We’ll cover a set of topics we think are essential to ask of any technology that helps you deliver chat experiences.

Note: This comparison was created based on documentation and resources freely available online from Sendbird and PubNub. The content was last updated on 9 Feb 2023 for Sendbird Chat, and on 20 Feb 2023 for PubNub Chat. Be sure to double-check everything before you make any decisions. If you do find anything incorrect or out of date, then please let us know.

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Performance, reliability, scalability, and messaging guarantees

Before considering anything else, you need to trust your chat provider can deliver a dependable service at scale. Performance, reliability, scalability, and superior messaging guarantees are critical factors for any solution that enables the building of chat applications. These characteristics directly impact the user experience and can make or break the success of any chat experience.


Sendbird Chat

PubNub Chat

Uptime guarantee


This amounts to roughly 8h 40m of service downtime/unavailability per year. 

99.999% uptime SLA for customers with the Pro package.

Unclear if any SLA is provided for the Starter and Free tiers.



PubNub advertises sub-250ms worldwide latencies.


Claims it can scale to 1 million+ concurrent connections per client app.

Public chat channels can sustain up to 100K users.

Private chat channels are limited to 20k users.

Claims it can handle unlimited concurrent connections and unlimited channels.

Infrastructure / datacenters

The Sendbird infrastructure consists of 8 datacenters distributed in different regions (US West & East, Europe, Asia Pacific, Australia).

PubNub has 15 datacenters distributed globally.

Multi-region architecture


You are required to choose a single AWS data center for an app to reside in. This can lead to increased latency, and negatively impacts reliability and availability - if the region goes down, then all apps hosted there are affected.


PubNub has a globally-available mesh architecture with no central point of failure. Additionally, PubNub supports latency-based routing and multi-region data replication.

Guaranteed message ordering


We have not identified any documentation that indicates whether or not Sendbird Chat guarantees message ordering.


PubNub does not guarantee message order and in general does not guarantee that messages are stored or sent in the exact same order in which they are published.

Guaranteed message delivery


We have not identified any documentation that indicates what kind of messaging semantics are supported by Sendbird Chat.


PubNub is not a guaranteed message delivery service.

Automatic reconnections with continuity

Sendbird Chat SDKs supports automatic reconnections (for scenarios where clients briefly disconnect). 

However, it is unclear if upon reconnection no message will be lost, sent multiple times, or delivered out of order.

PubNub SDKs support automatic reconnections.

However, there’s a queue limit of 100 messages. If more than 100 messages are published while a chat user is disconnected, older messages will get discarded, and will never be delivered to the user once they reconnect.

Ship chat experiences you can trust to deliver at scale

Ably is a solid foundation for any chat app. Our platform offers <65 ms round trip latency for 99th percentile, guaranteed message ordering and (exactly-once) delivery, global fault tolerance, and a 99.999% uptime SLA. In addition, our multi-region infrastructure can scale to handle millions of concurrently-connected devices. 

Learn more about Ably’s guarantees and our globally-distributed infrastructure

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Chat features

It’s natural you’ll want to make sure the platform you choose for chat has a robust feature set, provides the functionality you need right now, and has the functionality to support you as you grow and your needs change. 


Sendbird Chat

PubNub Chat

1-to-1 chat



Group chat



Private and public group chat



Chat & UI components

Yes (React, React Native, iOS, and Android).

Yes (React, React Native).

Push notifications



Message history (persisted data)



Rewind / load previous messages



User presence



Advanced features

Diverse feature set, including:

- Typing indicators
- Message delivery receipts & read receipts
- Reactions
- User and channel mentions
- Unread message count
- Scheduled and offline messages
- Channel list
- Message and user moderation (e.g. profanity filter, mute user)
- Multimedia support (audio, video, photos)
- Offline messaging

You can implement various chat features, such as:

- Typing indicators
- Message delivery receipts & read receipts
- Reactions
- Mentions
- Unread message counts
- Mute/ban users
- Spam prevention
- Image and file sharing
- Update/delete messages

Deliver feature-rich chat experiences with Ably

1:1 and group messaging over pub/sub channels, presence, reactions, typing indicators, authentication, and many more. Get started in minutes with our chat apps reference guide.  

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Supported languages, integrations, and protocols

The modern internet is a web of different programming languages, platforms, protocols, and services built on top of other services. This isn’t likely to change anytime soon, so a chat provider that offers SDKs in different languages, 3rd party integrations, and multi-protocol capabilities is what you should be aiming for. 


Sendbird Chat

Stream Chat


Client SDKs:

- iOS
- Android (Kotlin)
- JavaScript
- Unreal
- Unity
- .NET
- Flutter

Client SDKs:

- React Native
- Flutter
- Swift
- Redux
- Kotlin
- Unity

3rd party integrations

Limited number of integrations:

- Chatbot interface that allows you to add your own chatbot that can send and receive messages.
- Custom webhooks to send data to your servers/systems.

Sendbird Chat offers no integrations with components like databases, event streaming platforms (e.g., Kafka), or serverless platforms.

PubNub offers integrations with tools such as:

- Agora and Vonage (for voice and video calls).
- Amazon SQS and Amazon Kinesis (for backend streaming).
- Cloudinary (image manipulation).
- Google Translate, Amazon Translate, Microsoft Translator (on-the-fly translations).
- Microsoft Azure Bot Service and Amazon Lex (chatbots).


WebSockets are used to maintain persistent connections between the Sendbird server and client SDKs. The documentation doesn’t indicate whether or not a fallback transport is supported (useful for environments where WebSocket connections are blocked).

The Sendbird Chat Platform API uses HTTP.

Sendbird Chat doesn’t support any other messaging protocols, such as MQTT, SSE, or AMQP. 

Unlike other chat solutions, PubNub doesn’t support WebSockets. Instead, HTTP long polling is the transport protocol used for communication between the PubNub server and client-side chat SDKs/components. 

PubNub also supports MQTT. 

Build chat experiences using your preferred tech stack with Ably’s help 

We offer 25+ client SDKs targeting all major languages, managed integrations with services like Kafka, Terraform, AWS Lambda, and multi-protocol capabilities (WebSockets, SSE, MQTT, and more).

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Security and compliance

Security and compliance are front of mind for many live chat use cases. Encryption, authentication, roles and permissions, and compliance with standards like SOC 2 are essential requirements for any chat solution.


Sendbird Chat

PubNub Chat


TLS/SSL and AES-256 encryption

TLS and AES-256 encryption.


Access tokens and ephemeral session tokens.

Also supports JWTs (but you will have to reach out to Sendbird support first to enable this functionality).

Secret keys (server-side), and tokens (including ephemeral ones) for clients connecting to PubNub.

There is no support for JWTs.

Configurable  chat roles & permissions




ISO 27001, HIPAA, GDPR, SOC 2.

GDPR, SOC 2, CCPA, HIPAA (the latter is only available for Pro customers).

Data governance

Data is stored by Sendbird.

Data can be stored by PubNub for any length of time (it comes at a cost, see the pricing and support section below for details).

You can use PubNub Functions to asynchronously move JSON messages to your own DB.

Deliver highly secure & compliant chat experiences with Ably

Benefit from flexible authentication (including API keys and JWTs) with fine-grained access controls, SSL/TLS, 256-bit AES & end-to-end encryption, and compliance with SOC 2, HIPAA, and EU GDPR. 

Learn more about Ably’s security and compliance.

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Pricing and support

Is the pricing model flexible, scalable, and clear? What support options are available?


Sendbird Chat

PubNub Chat

Free package

The free package allows a maximum of 100 monthly active chat users (MAUs) and 10 peak concurrent connections.

The free package allows you to build a proof of concept. There are no guarantees around latency, and there’s a 200 monthly active users (MAUs) limit.

Pricing model

There are 3 paid tiers: Starter (from $399/ month), Pro (from $599/ month), and Enterprise (custom pricing).  

The Starter and Pro tiers start from 5k MAUs, while the Enterprise tier is advertised as being suitable for use cases with millions of MAUs.

There are some feature availability differences between the 3 tiers. For example, the Starter tier can’t implement delivery receipts, and can only use limited chat moderation features. Another example - the Enterprise tier comes with paid add-ons (e.g., private dedicated servers) that aren’t available for the other tiers.    

Pricing increases as the number of MAUs increases. For example, the Starter package with 25K MAUs costs $1.199/ month. The Pro package with 25K MAUs is as expensive as $1.799/ month.

Note that there’s a cap on the number of peak concurrent connections: 5% of MAUs. If you exceed the number of MAUs or peak concurrent connections, you will have to pay for overages. It’s unclear how much you’ll be charged for overages, but it’s something to bear in mind if you have a growing number of MAUs, and you’re expecting bursts of chat clients connecting simultaneously.

There are 2 paid tiers: Starter (suitable for pilot or small-scale apps), and Pro (for larger-scale apps).

The Starter tier starts from $49/month + MAUs (it’s unclear how much you’ll be charged per user). This tier doesn’t include HIPAA compliance.

The pro plan offers custom pricing (MAUs / transaction pricing), depending on use case and scale. It’s impossible to estimate how much you would be charged without contacting sales, as there are no pricing examples provided. 

PubNub data storage comes with additional costs (irrespective of tier):

8$/GB/month for messages, message actions, permissions, metadata, key-value pairs (PubNub Functions), and channel groups

1.99$/GB/month for files

Note that 3 out of 4 support plans are paid (see below for details).

Customer support

The base customer support plan (which is included in any paid package) offers best-effort response time, irrespective of the issue’s priority. The base plan is available for 9 hours per day.

There are also 4 paid support plans (L1-L4). For example, L4 costs 10% of your monthly expenditure (or a minimum of $10.000/month). It comes with a guaranteed response time of 1-6 hours (depending on issue priority). L4 support is available 24/7, and there are some extra benefits (e.g., customer success manager).    

There are 4 support plans:

- Free support (available by default with all free and paid tiers). Done via email. There is no guaranteed response time or support availability.  

- Gold support (the greater of $500/month or 4% of usage bill). Support is available 24/5, and response time is guaranteed to be within 4 hours. In addition to email support, you have access to realtime operational dashboards.

- Platinum support (the greater of $1.500/month or 6% of usage bill). Support is available 24/7, with a 2-hour response time guarantee. Extra support channels include Slack and phone.

- Virtual event support ($399 /hour). It’s the package recommended for live streaming and entertainment apps. It comes with dedicated event support agents and realtime monitoring and dashboards.

Transparent, usage-based pricing to deliver chat experiences at scale

With Ably, you pay for the messages, peak active channels, and peak connections you use for the month. No hidden costs. Learn more about Ably’s pricing

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Sendbird vs PubNub: which platform has the best chat API?

This isn’t a question we can answer outright. Both Sendbird Chat and PubNub Chat have their pros and cons when it comes to delivering chat experiences. Here’s a recap of the major similarities:

  • Both Sendbird and PubNub are compliant with GDPR, SOC 2, and HIPAA. 

  • There are some question marks around data integrity (superior messaging QoS) with both solutions. PubNub does not guarantee message ordering and message delivery, especially when brief disconnections are involved. It’s unclear whether Sendbird can guarantee message ordering and delivery in poor/unstable network conditions.

  • Both Sendbird and PubNub have a rather opaque pricing model. With Sendbird, if you exceed the number of MAUs or peak concurrent connections allowed by your package, you will have to pay for overages. However, it’s unclear how much overages cost. With PubNub, you are forced to contact sales to find out how much it costs.

  • Both Sendbird Chat and PubNub Chat allow you to deliver 1:1 and group chat experiences with chat and messaging features like typing indicators, presence indicators, message delivery and read receipts, reactions, and mentions. 

And here are their main differences:

  • PubNub uses HTTP long polling for realtime communication between client and server, while Sendbird uses a superior alternative - WebSockets.

  • PubNub Chat seems to be a more scalable solution - it claims there’s no cap on the number of channels and concurrent users (connections). In contrast, Sendbird Chat can scale to 1 million+ concurrent connections per client app, and group chats are limited to a maximum of 20.000 users (private channels) / 100.000 users (public channels).

  • PubNub Chat is more reliable - it’s a multi-region solution, and it offers a 99.999% uptime SLA to customers with the Pro package. Meanwhile, Sendbird is a single-region solution; you have to choose a single region / datacenter for a chat app to reside in, and the uptime SLA is 99.9%.

It is ultimately up to you to decide if Sendbird Chat or PubNub Chat is the best choice for your specific chat use case. There are, of course, alternative solutions you can use to deliver chat experiences:

Some of them, like Ably, offer a comparable feature set, and superior guarantees around reliability, availability, data integrity, and performance at scale.

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Discover Ably, your PubNub & Sendbird alternative for shipping chat experiences at scale  

Ably is a realtime experience infrastructure provider. Our realtime APIs and SDKs help you build live chat experiences, without having to worry about managing and scaling messy realtime infrastructure. 

We offer flexible building blocks like pub/sub messaging, presence, and message interactions, so you can build rich 1:1 and group chat experiences, with features like online/offline status indicators, reactions, typing indicators, and read receipts. 

Our globally-distributed, multi-region infrastructure offers unrivaled guarantees around performance, data integrity, reliability, and scalability:

  • <65 ms median latency

  • Guaranteed message ordering and (exactly-once) delivery, even in unreliable network conditions

  • Redundancy at regional and global levels, with a 99.999% uptime SLA

  • Dynamic elasticity, with the ability to send billions of messages to millions of channels and chat users

Learn how Ably compares to Sendbird Chat and PubNub:

Ably vs Sendbird Ably vs PubNub


Power not only chat, but all your realtime use cases with Ably

Ably goes far beyond live chat. We can help you with many other realtime use cases: