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Ably vs PubNub

Let us help you discover why Ably is clearly the better choice.

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Why it matters?
Example pricing comparison: *
  • 100k customers per month
  • 200k sessions per month
  • 42 messages per session
  • 8.4m messages - pub/sub
  • 8.4m messages - history
  • Peak 5k connections (assumed from 100k customers)
* Based on example provided on PubNub's pricing page on 31 Aug 2018
$96.99 per month $452 per month  

Our flexible packages ensure we deliver value to our customers who pay for what they use, and automatically benefit from volume discounts.

See how much you can save
Simple usage based pricing  

Ably's pricing is simple and transparent. You pay for the messages, peak active channels and peak connections you use for the month. You can either pay for what you've used at the end of the month, or reserve capacity in advance each month and benefit from a discount.

PubNub packages, like Ably's are also transparent - you pay for the resources you use. However, pricing is based on transactions which are classified into 4 different types, making it difficult to predict ongoing costs.

See Ably's pricing calculator
Global datacenters locations 16 14

As we have 16 datacenters globally, we can ensure that your users always experience the lowest possible latency by connecting to the closest datacenter, and have complete availability by connecting to alternative healthy datacenters when necessary.

PubNub has datacenters in EU Central, EU West, Asia Pacific, US West, US East, South America.

Find out more about Ably's datacenters
Latency based routing

Both Ably and PubNub offer latency based routing that ensures users anywhere in the world connect to the closest datacenter available to them.

Find out more about Ably's latency based DNS
Binary encoded messages

Encoding messages in binary format is faster. It reduces bandwidth to send and receive messages, and streamlines the processing time for clients and servers when encoding and decoding messages.

PubNub does not support binary encoded messages.

Find out more about our binary protocol
Redundancy and Reliability
Mesh architecture / no central point of failure / self-healing cluster

The Ably platform is designed with no single point of failure and to be self-healing. All our customers benefit from their apps running on all of our datacenters providing resilience, reliability and low latencies globally.

PubNub's platform is also distributed.

Find out more about Ably's mesh architecture
Autonomous datacenters

Ably's servers are located in 16 datacenters covering 4 continents with each datacenter designed to operate as part of the global cluster when available, but operate autonomously when necessary.

Find out where Ably's servers are located
Data replicated in multiple regions Partial

Ably stores every message in at least two datacenters and separate geographical regions. This ensures that an outage in any datacenter or region cannot result in data loss.

PubNub only guarantees full data replication for their Pro (equivalent to our Enterprise) plans.

Find out about Ably's message delivery guarantee
QoS & message delivery guarantee Partial

Ably provides guaranteed message delivery and continuity across disconnections. Publishers only receive an ACK when data is persisted in two locations, and subscribers never lose data during brief disconnections as we maintain connection state for each client on our servers.

PubNub imposes a message queue limit of 100 messages so cannot guarantee that message recovery is possible and thus all subscribed clients will receive all published messages"

Find out about Ably's QoS and message delivery guarantee
100% uptime guarantee

Ably uniquely offers a 100% uptime guarantee to all Business and Enterprise customers. We stand by our 100% uptime promise - if we are unable to meet that goal, we offer refunds.

PubNub provides a 99.999% uptime SLA available for their Pro packages (equivalent to our Enterprise packages).

Find out about Ably's 100% uptime guarantee
WebHooks Partial

Ably's WebHooks provide a means to get messages, channel lifecycle and present events pushed to your servers over HTTP.

PubNub supports WebHooks if you request them manually through support, however they are limited to presence events and do not cover channel lifecycle events

Find out more about WebHooks
Serverless cloud function invocation Partial

Ably can trigger serverless functions on any third platforms such as Amazon Lambda, Microsoft Azure or Google Function.

PubNub allows you to run code on their own platform using their proprietary PubNub Functions. The code you can run in Blocks is limited to the Javascript API available in their system.

Find out more about Reactor Functions

Presence allows you to subscribe to events when users or devices enter or leave channels. This is a useful feature for collaborative apps, games and chat rooms.

In addition to the features that PubNub offer, Ably supports a configurable number of presence members. PubNub supports a default announcement of 20 members and a self-configurable maximum of 100 members per channel. Ably supports 200 by default and far more upon request.

Find out more about Presence
Message history

Ably's message history feature provides a means for clients or servers to retrieve messages that were previously published on a channel.

Find out more about our History API
Realtime data firehose

Stream your realtime data published within the Ably platform directly to another streaming or queueing service such as Amazon Kinesis, Apache Storm or Kafka.

Find out more about our Reactor Firehose
Reliable message ordering

Ably ensures that messages are delivered to persistently connected subscribers in the order they were published on each channel.

PubNub does not provide these guarantees and recommends you manage ordering yourself.

Find out more about reliable ordering
Push notifications

Both PubNub and Ably offer push notifications.

Find out more about Push Notifications
Message and worker queues

Data published into Ably's realtime system can be moved into traditional message queues for realtime or batch processing.

PubNub does not offer any message queuing features or ways to distribute data using once-only pattern to your server workers. However, PubNub has recently launched Blocks which appears to be an alternative function-as-a-service approach.

Find out more about our Queues
Custom domain endpoint (CNAME)

Ably supports custom domains for our Enterprise customers allowing them to connect to Ably using a CNAME such as "".

PubNub only provides support for custom CNAME for non-TLS connections as they do not serve up custom certificates for customers.

Find out more about our custom domains
Client libraries and protocol support
Native client libraries for every popular platform

Both Ably and PubNub offer a considerable range of client libraries for every popular platform.

View our client library SDKs
Ably protocol support

Ably's realtime protocol provides an efficient means to reliably and efficiently publish and subscribe to realtime data.

PubNub supports their own protocol.

See which libraries natively support the Ably protocol
PubNub protocol support

The Ably platform is designed to be protocol-agnostic and ensure protocol interoperability. We support PubNub's protocol and ensure interoperability with Ably's protocol and the other protocols we offer.

Learn more about our Protocol Adapters
MQTT support

The Ably platform is designed to be protocol-agnostic and ensure protocol interoperability. Ably supports MQTT.

PubNub supports MQTT.

Find out which protocols we support
SSE protocol support

The Ably platform is designed to be protocol-agnostic and ensure protocol interoperability. That's why we support SSE. PubNub does not support SSE.

Find out which protocols we support
White-label browser library

Ably can provide a white-labelled browser Javascript library with a namespace of your choosing and no reference to Ably in the code.

PubNub does not, as far as we are aware, offer white-label libraries.

Find out about our white-label libraries
Continuity and connection state recovery Partial

Ably provides continuity for clients that become disconnected for reasons such as going through a tunnel or changing networks. Ably stores the connection state for each client on its servers so that clients that reconnect within two minutes can resume their connection and receive all messages published whilst they were disconnected.

PubNub imposes a message backlog limit of 100 messages so cannot guarantee that message recovery is possible. Also, PubNub provides no indication as to whether you have recovered all messages or not which makes it very difficult for developers to build apps that rely on this feature.

Find out more about connection state recovery
1st class WebSocket support

PubNub uses HTTP as the transport for their client libraries. A WebSocket compliant interface is provided in some libraries, however this is just a wrapper around an underlying HTTP transport.

View our supported transports
Fallback to Comet (XHR) and Long Polling for older browsers

Whilst most modern devices support WebSockets, there are situations where the device or the network environment requires use of HTTP transports.

View our supported transports
TLS connection

Both Ably and PubNub offer TLS connections ensuring that all data in transit is encrypted.

Find out more about SSL/TLS
Token based authentication

Token based authentication ensures your private key is never shared and instead a short-lived token is used to authenticate.

Ably allows configurable policies and an identity to be embedded in a token ensuring you have complete control over what actions your users can perform such as limiting which channels they can subscribe or publish to.

PubNub offers an authentication scheme called PAM that allows granular permissions to be configured per client. These permissions are stored on PubNub's servers however which means it is your responsibility to keep a client's permissions in sync with PubNub at all times.

Find out more about Ably's authentication
JSON Web Token support

Using JWT allows for easy integration with your existing authentication systems, along with ensuring your private key is never shared.

Ably allows for not only Ably Tokens to be embedded within JWTs, but also for JWTs to be signed by Ably API keys and used themselves for authentication.

PubNub does not support JWT.

Find out more about using JWT with Ably
Configurable private key permissions

Ably provides support for private API keys with configurable permissions including restrictions on channels or operations.

PubNub does not support configurable permissions for keys.

Find out more about API keys
Configurable channel permissions

Ably provides channel rules providing you with the flexibility to maintain control of your channels, such as requiring SSL/TLS or only identified authenticated clients on a channel.

PubNub too allows channel rules to be configured.

Find out more about channel rules
Encrypted message payloads

Ably's AES encryption allows messages to be encrypted using the provided private key before they are published to Ably. As a result, messages are practically impossible intercept and view for anyone including Ably. For very sensitive data, this ensures you can safely use us knowing your payloads are always secure and opaque.

PubNub too provides AES encryption in its libraries.

Find out more about Ably's encryption
Other important stuff
Theme tune

Unfortunately at Ably we've not had the time to create a theme tune. We're working hard to play catch-up to PubNub on this front :)

See and hear PubNub's theme tune

* All information regarding our competitors was obtained on or before January 2016. It is therefore possible that some of this information may now be out of date. If you believe that any of this information is incorrect, please get in touch with us so that we can correct it immediately.

Migrating to Ably

Join the others and upgrade your realtime platform.

  • PubNub protocol adapter - migrate in minutes

    Ably's platform is designed to be protocol agnostic and supports amongst other protocols, the PubNub protocol. Customers wishing to move across to Ably can do so progressively by using their existing PubNub client library integrations directly with the Ably platform.

    Find out more about protocol adapters
    Find out more about protocol adapters
  • Technical migration assistance

    We're happy to offer technical assistance from our engineering team to customers moving across from PubNub.

    Get in touch for help
    Get in touch for help

Some customers who have already migrated over from PubNub to Ably...