A Crash Course in Functions

PubNub offers a Publish-Subscribe API that enables the rapid transmission of small messages between internet-connected devices, with messages typically delivered in under 0.25 seconds. This network is supported by multiple global points of presence, ensuring low latency and continued operation even if data centers fail. PubNub provides over 70 SDKs for various programming languages and devices, making it suitable for real-time, event-driven applications like chat messaging, live updates, IoT signaling, and more. Developers can enhance these capabilities through PubNub Functions, which allow the execution of custom code to augment, transform, or filter messages during transmission, enabling use cases such as real-time language translation, data analytics, and secure API calls. Functions are further categorized into four event handlers—Before Publish or Fire, After Publish or Fire, After Presence, and On Request—each serving unique purposes like mutating message contents, triggering alerts, or acting as a REST API. The Functions feature includes tools for securely storing API keys, managing application state, and integrating with third-party APIs, supported by a library of over 80 open-source Function event handlers available through the PubNub BLOCKS Catalog.