Latency
Definition.
Latency: The delay before a transfer of data begins following an instruction for its transfer.
In More Detail
Latency is time-to-first-response, and it is distinct from throughput. A system can move a lot of data and still feel slow, which is why 'we have plenty of bandwidth' does not answer a complaint about sluggishness.
Physical distance sets a floor you cannot optimise past, which is the argument for putting servers and CDN edges near users. Above that floor, the usual wins are removing round trips rather than speeding any single one up — one query that returns what you need beats five that each wait on the last.
In Practice
This is one of the practical reasons timezone and server-region choice matters for international clients — hosting a backend in a region close to your actual user base cuts real, measurable latency versus defaulting to wherever is cheapest.
Related Terms
Browse the full software development glossary, or see the frequently asked questions.
If you are working out whether this applies to your own project, the case studies show where it turned up in real builds, services lists what I take on, and pricing gives the starting figures.
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