Note: I'll try to include the most relevant metrics on the Part 4 of my Front End Developer Automation series. If you'd like to collaborate, please let me know @papaponmx.
For me the depending on the topic, some of those are:
<meta>tags presence and confirm that they include relevant content.
- Validate all
- First meaningful paint.
- Number, size and latency of initial requests and their relevance.
- Font sizes and images size on mobile devices.
- Color contrast ratio.
- Can I traverse the app just with the keyboard?
What are yours?