Realtime feedback on TimeToLargestContentfulPaint

Shopify Apps

Topic summary

Concern about diagnosing high Time to Largest Contentful Paint (LCP) in a Shopify app’s Admin performance report. LCP (Largest Contentful Paint) measures how quickly the main content becomes visible; the report flags it as too slow.

Key issues:

  • Data delay: Performance stats lag by 2 days (e.g., on the 26th only data for the 24th is available), hindering iteration.
  • Lack of diagnostics: The report provides no indication of root causes or which assets/components drive the long LCP.

Requested outcome: Guidance on how to obtain real-time or near real-time feedback to identify and fix the LCP problem, rather than waiting on delayed aggregated data.

Status: No solutions or next steps presented; the question remains open and unresolved.

Summarized with AI on December 26. AI used: gpt-5.
1

In my app’s admin performance, it indicated TimeToLargestContentfulPaint (LCP) was too long. And the data provided by Shopify has 2 days of lag, i.e. today is 26th, but it is showing stats for 24th.

It also gave no indication of what could be causing this high LCP.

How do I get realtime feedback? Otherwise it is impossible so solve this, I have wasted 1 week on it already.