PubNub ensures reliable message delivery during poor network conditions or reconnections through message persistence and timetoken-based catch-up. Message persistence ensures no data is lost even if a device is offline for an extended period. Timetoken-based catch-up enables precise resumption, minimizing the risk of duplicate or missed messages. Built-in reconnection logic in the SDKs ensure that most network issues are handled seamlessly, so end users rarely notice disruptions. Additionally, the low client complexity—thanks to PubNub abstracting much of the logic within its SDKs.

With PubNub, there's no need to manually implement complex reconnection logic or message buffering

As a fully managed cloud platform, PubNub delivers global scalability and minimal operational overhead—but your app’s real-time features rely on internet connectivity and our infrastructure. While service disruptions are rare, they can impact live experiences. Our real-time network status is always available at status.pubnub.com

PubNub is purpose-built for real-time communication—not for heavy data storage or complex backend logic. That’s why we offer a wide range of eady-to-use integrations with databases, serverless platforms, auth providers, and more—so you can easily build complete, reliable, real-time applications.

Yes, PubNub has a global edge network with Points of Presence (PoPs) in key regions: North America, Asia, Europe, and South America. This ensures data is routed through the closest servers to users, minimizing latency and improving real-time performance.

On average, PubNub delivers messages in under 100 milliseconds worldwide, thanks to its optimized infrastructure and intelligent routing.

PubNub also offers a 99.999% uptime SLA (Service Level Agreement), meaning it's built for high availability and reliability, even under heavy load or across distributed geographies

PubNub utilizes a Publish/Subscribe (Pub/Sub) messaging model to deliver real-time communication across devices, eliminating the need for users to manage infrastructure. Publishers send messages to named channels (topics), and all subscribed clients receive them instantly. This decouples senders from receivers, enabling scalable, low-latency messaging with no need to handle servers, sockets, or scaling logic.

PubNub’s architectural foundation is a highly optimized, globally distributed Publish/Subscribe system designed for real-time messaging at planetary scale. It abstracts away the complexity of scaling, securing, and managing real-time infrastructure, allowing developers to focus purely on building applications that react instantly to data. By combining a robust Pub/Sub backbone with layers like user access control, message persistence (history), presence tracking (state detection), and edge functions (serverless), PubNub enables a broad range of real-time use cases (chat, live dashboards, multiplayer games, streaming & location tracking) with minimal development and operational overhead.

Channel-Based, Real-Time Pub/Sub Architecture

PubNub structures communication around string-based channels, enabling granular or broad message targeting. Channels can represent chat rooms, IoT devices, user sessions, or system events, allowing millions of concurrent streams without conflict.

Clients subscribed to a channel receive published messages within ~100 milliseconds (ultra-low latency), thanks to PubNub’s globally distributed edge network, which minimizes delay by routing through the nearest data center(PoP).

Unlike request/response systems, PubNub’s Pub/Sub model is asynchronous — messages are pushed to subscribers in real time, enabling use cases like chat, live dashboards, multiplayer games, and location tracking.

The decoupled architecture supports massive scalability: publishers don’t track subscribers, and channel topologies are dynamic. Edge-based stateless routing supports ephemeral messaging, while TLS and PubNub Access Manager (PAM) provide encryption and fine-grained, token-based access control.

Beyond core messaging, PubNub offers presence detection, message persistence, and PubNub Functions — a serverless layer injecting logic (e.g., filtering, enrichment, validation) directly into message streams without extra backend infrastructure.

This architecture powers real-world applications such as live support chat, IoT telemetry, collaborative editing, and real-time asset tracking.