Performance
Speed Lens
See exactly which app is costing you conversions.
★ 4.8 rating3,400+ installsFree plan availableShopify & Shopify Plus
What It Does
Per-app attribution
Every script on the page is traced back to the app that injected it, with its cost in milliseconds.
Real user monitoring
Field data from actual customer sessions, segmented by device and connection type — not lab scores.
Regression alerts
Get notified when a theme change or app install pushes any template out of the green.
Template-level breakdown
Home, collection, product, and cart tracked separately, because they fail for different reasons.
The problem with Lighthouse
A lab score on your laptop tells you very little about what a customer on a three-year-old Android over patchy 4G experiences. Speed Lens collects field data from real sessions and segments it the way it actually varies: by device class, connection, and template.
Attribution is the useful part
Knowing your LCP is 4.2 seconds is not actionable. Knowing that 1.6 seconds of it comes from a review widget you could replace with a theme section is.
Speed Lens traces every script back to its source app and gives you a ranked list of what to remove, replace, or defer — sorted by the time you would get back.
Free tier
The free plan covers one store with seven days of history, which is enough to run an audit. Paid plans add alerting, longer retention, and per-template trend history.
Screenshots
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5.0 Rating
50+ Brands
Shopify Plus Partner
