Buried at the end of this year's instalment of my semi-annual series on network and device reality is a mystery: multiple, independent data sets from the Web Performance community indicate sites built as Single-Page Applications ("SPAs") receive, on average, only one (1) "soft navigation" for every

PerfPlanetCal is a curated calendar of web performance events, conferences, and meetups around the world. Through event listings, PerfPlanetCal offers insights into web performance topics, including performance optimization techniques, browser performance tools, and user experience metrics. Developers and performance enthusiasts can discover opportunities to network with peers, learn from industry experts, and stay updated with the latest trends in web performance.

Web Performance Calendar

Real-world data from multiple sources reveals that Single-Page Applications (SPAs) average only one soft navigation per hard page load, suggesting users don't generate long sessions. This challenges the fundamental trade-off SPAs offer: accepting higher upfront JavaScript costs for faster subsequent interactions. If sessions are truly this shallow, SPA architectures may represent an industry-wide mistake outside specific use cases like document editing or chat. The web performance community needs to investigate whether this data accurately reflects reality, understand what interactions are being measured, and use these insights to steer teams toward more appropriate architectures based on actual session depth rather than FOMO-driven technology choices.

The Curious Case of the Shallow Session SPAs