Message Delivery Guarantees

PubNub automatically handles Network Interruptions

Our automatic reconnection process is designed to handle brief network interruptions like driving through a tunnel, switching from WiFi to cellular, etc.

Every channel has its own dedicated message queue, which acts as a temporary buffer so clients can catch up automatically once they regain network connectivity. By default, each queue will hold a hundred messages for up to 20 minutes, but these values can be extended to thousands of messages per second for as long as needed, catering to even the most unreliable connection.

PubNub offers unlimited long-term storage

Enjoy unrestricted storage of both files and messages, allowing you to fetch historical data instantly regardless of how long it has been stored.  With vast amounts of data being stored, management of that storage is important - easy to do using PubNub’s flexible APIs.

PubNub has Ordered Message Queues

Every queued message has a serial identifier that uniquely locates that message within the queue, allowing us to guarantee message ordering on the server. Further, clients can define their own order sequence number (‘seqn’), received at all subscribers to provide full end-to-end message ordering.

As solutions scale, so will the number of message queues, but PubNub’s sophisticated Routing Mesh ensures subscribe API calls will always be directed to the correct backend container; this means we can guarantee that the correct message queue is ready in memory for the subscribing client, boosting performance.

PubNub will Bundle Transactions together, Reducing your Costs

Every time you make an API request with PubNub, for example, if you receive data from a channel subscription or retrieve messages from our persistent storage, we will compress and bundle those responses together without impacting performance.  

Since our transactions are billed in 2KB chunks, you can effectively combine multiple messages into a single transaction.  At the extreme, with 20-byte messages, you could fit 100 messages into a single transaction, meaning a 100x reduction in costs compared with services which bill per-message.