Latency

Definition

The time delay between a client making a request and receiving a response, representing the round-trip travel time of a data packet across the network.

What Problem It Solves

Latency tracking solves the problem of diagnosing slow user experiences by measuring the literal round-trip time of data packets. Understanding latency allows developers to optimize network routing, reduce database queries, and position assets closer to users via CDNs.

What Happens If Not Used

Without monitoring and optimizing latency, applications feel slow and sluggish regardless of bandwidth. This causes poor user experiences, reduced user engagement, and ultimately leads to high abandonment rates and loss of revenue.

Easy Wording

The waiting time or "lag"—how long it takes for a message to travel from your device to the server and back.

Layman Example

If you shout into a canyon, latency is the time that passes between you shouting and hearing the echo bounce back.

Technical Example

We can measure latency using the ping utility in the terminal:

ping google.com

Which yields:

Reply from 142.250.190.46: bytes=32 time=15ms TTL=117

The time=15ms represents the latency (15 milliseconds) of packet transmission.