September 2019 Summaries

This article compares two popular choices for realtime applications - WebSockets and Server-Sent Event (SSE) APIs. WebSockets provide a full-duplex, low-latency, event-driven connection between the server and browser, ideal for realtime apps. They use a custom ws protocol to transport messages at a lower level than HTTP and are useful for applications that require data to be read from and written to the server such as chat apps or multiplayer games. WebSockets have bi-directional communication in realtime but may face issues with some enterprise firewalls and lack built-in support for reconnection. Server-Sent Events (SSEs) are based on Server-Sent DOM Events, allowing browsers to subscribe to a stream of events generated by a server using the EventSource interface. They use XHR streaming to transport messages over HTTP and are useful for apps that only require reading data from the server such as live stock or news tickers. SSEs have built-in support for reconnection, no issues with enterprise firewalls, but can't handle binary data and have a limit of six concurrent open connections per browser. The choice between WebSockets and Server-Sent Events depends on the use case. WebSockets are more complex and demanding but provide a full-duplex TCP connection useful for multiplayer games, chat apps, or location-based apps. SSEs are better for simple cases where you don't need two-way messaging such as read-only realtime apps like stock tickers or news updates.

Ably, a realtime data delivery platform, has been selected to power live scores for the Laver Cup, a fast-paced team tennis tournament with a global fan base and commercial partners. This follows two years of providing reliable scoring systems at the Australian Open Tennis Tournament, where Ably streamed live scores to 1.2 million viewers globally. The company's infrastructure supports the high-speed nature of play at the Laver Cup, enhancing commercial opportunities around fan engagement.

Over the last 18 months, Ably has seen significant growth in its data stream network, with daily message distribution increasing by almost 200%. The company's technology is used by various industries, including HubSpot, Turing Group, and Tennis Australia. Key product optimizations include enhanced interoperability, next-gen APIs, and improved reliability. Realtime API Management has been introduced through the Ably API Streamer, making it easy for developers to publish and manage realtime data streams as APIs. The Ably Open Data Streaming Program allows developers to leverage open realtime data for free, promoting the open data movement and supporting the community.