Performance budgets are an essential but under-appreciated part of product success and team health. Most partners we work with are not aware of the real-world operating environment and make inappropriate technology choices as a result. We set a time budget of less than 5 seconds first-load Time-to-Interactive and less than two seconds for subsequent loads. We further constrain ourselves to a baseline device and network configuration to measure progress. 2017's global baseline is a ~$200 Android device on a 400Kbps link with a 400ms round-trip-time ('RTT'). This translates to ~130-170KB of critical-path resources, depending on composition; the more JS you include, the smaller the bundle must be.
The Performance Inequality Gap
As long as we continue to build only for wealthy users, the dream of a web for everyone will continue to recede before our eyes, leaving a once vibrant ecosystem a ghost-town. Creating a better web starts with respecting the limits of the hardware and networks that most of the world's users carry. This is a deep dive into those constraints, their progression, and what they mean for web developers and the tool vendors that support them.
What we're doing now isn't working. Not by a long shot.
A lot has changed since 2017 we I last estimated a global baseline for total page resource limits of 120-170KiB. Thanks to progress in networks and browsers (but not devices), the new baseline is much more generous: ~100KiB of HTML/CSS/fonts and ~300-350KiB of JS. But the devil's in the footnotes, and modern web development practices push the median page well above these guidelines.
Is there a generic, unform way to think about web performance? What is web performance? What's it for? A humble attempt to answer those very deep questions. [republished]
Despite advances in browser tooling, automated evaluation, lab tools, guidance, and runtimes, modern teams struggle to deliver even decent performance with today's popular frameworks. This is not a technical problem per se. It's a management issue, and one that teams can conquer with the right frame of mind and support.