Slow is the new downtime. What you once feared from a downed website — decreased conversion rates, lower page ranks, abandoned carts — now applies to a slow-loading experience. Problem is, slow is more nuanced than downtime; that is, while downtime is binary — the site’s either up or it isn’t — slow is in the eye of its beholder. It’s why asking what makes a slow website gets the same shrug from a developer as asking them how long an afternoon is.

Performance monitoring is great because it lets you see whether your application is fast or slow, and which parts need speeding up. For Node developers, those “parts” are most often endpoints handling incoming requests. Since the introduction of our performance monitoring offering in July 2020, Node devs have been able to use the Sentry SDK, @sentry/node, to measure the total time it takes to process each request, but we made some significant improvements since then.