Interaction Latency

Time from user tap to action successfully completed.

When to Use

• "Add to cart" button tapped → cart updated
• "Submit" button tapped → form processed
• "Like" button tapped → state changed
• Any tap that triggers async work

Measurement Pattern

TAP → START_SPAN → [async work] → END_SPAN

1. Capture tap timestamp
2. Start span with operation name
3. End span when action confirms success
4. Include success/failure outcome

Key Thresholds

| Rating | Duration | |--------|----------| | Good | <300ms | | Acceptable | <1s | | Poor | >1s |

Implementation

See references/ui-performance.md (Entry Point Latency section) for platform-specific code.

Common Mistakes

• Ending span on API call start (not completion)
• Not tracking failure cases
• Missing the tap timestamp (starting late)

Related Skills

• See skills/navigation-latency for screen-to-screen transitions (vs single-tap actions)
• Combine with skills/user-journey-tracking for friction detection on key interactions