Brian Rinaldi — Developer Experience Engineer / LaunchDarkly at Independent
What You Need to Know About the Serverless Edge
September 5, 2023
11:00
Performance
🇬🇧 English
Performance
How and why ($) to improve web performance in 2023
About
During this talk about web performance, you will discover how to make your website faster and more usable, and how this leads to an improvement in user experience and an increase of visibility of your site on search engines, even reducing digital marketing costs.
Andrea will share his extensive web performance experience and provide practical, high-impact, and easily applicable tips on how to improve performance in 2023.
Watch the full talk
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From the recording
Talk in brief
A field-oriented guide to improving web performance with evidence from real users rather than relying only on a fast development machine. The talk explains browser-collected field data, Core Web Vitals, and a prioritized set of changes with broad impact: optimize delivery through a CDN, reduce unnecessary JavaScript and long main-thread work, and reserve layout space for late-loading content. The emphasis is practical prioritization—measure the actual audience, fix the largest bottleneck, and verify the result under realistic devices and networks.
Key takeaways
- 01
Measure the experience inside real browsers
Field data captures the devices, networks, and interactions customers actually encounter, complementing controlled laboratory tests.
Watch from 6:21 - 02
Segment performance by real conditions
Aggregates can hide slow devices or connections, so teams should inspect representative audience groups and important journeys.
Watch from 11:05 - 03
Prioritize changes with proven broad impact
Large web datasets help identify interventions that are more likely to improve meaningful metrics across many pages.
Watch from 15:51 - 04
Reduce server and delivery latency
A CDN and an efficient origin can shorten the wait for documents and resources before rendering can begin.
Watch from 20:45 - 05
Reserve space to prevent layout movement
Explicit dimensions for images and embedded content let the browser construct a stable layout before resources arrive.
Watch from 30:55
Read edited transcript highlights
These concise notes were edited from automatic captions and checked against the talk structure. They are not a verbatim transcript.
Performance starts with the audience’s reality
A crawler or laboratory tool can reproduce a useful scenario, but customers browse with different devices, networks, caches, and behaviors. Browser field data captures those conditions at scale. Teams should use laboratory tests to diagnose repeatably and field data to understand whether the problem is common, severe, and visible on the journeys that matter.
Watch from 6:21One average can conceal many slow experiences
A global metric combines fast desktops, constrained phones, stable broadband, and intermittent mobile connections. That aggregate can look acceptable while a valuable audience segment struggles. Break results down by device class, geography, connection, template, and journey when possible, and test on representative equipment rather than the most convenient local setup.
Watch from 11:05Prioritization should follow likely user impact
Performance backlogs easily fill with small technical improvements. Evidence from large collections of real pages can identify patterns with broader effects and help teams begin with the bottleneck most likely to change the experience. After each intervention, measure again; a generic recommendation only becomes useful when the site’s own data confirms the gain.
Watch from 15:51Delivery time delays everything after it
The browser cannot render a document it has not received. An efficient origin, appropriate caching, compression, and a content delivery network can reduce the initial wait and bring resources closer to customers. Infrastructure does not replace page-level optimization, but slow delivery creates a floor that frontend changes alone cannot overcome.
Watch from 20:45Stable layouts require dimensions in advance
When an image or embed arrives without reserved space, the browser initially treats it as having no height and moves surrounding content later. Explicit dimensions or aspect ratios allow layout to be calculated before download completes. This simple contract improves visual stability and protects customers from clicking an element that suddenly changes position.
Watch from 30:55
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