What is Latency?
The time it takes for data to travel from A to B. High latency = laggy app. Low latency = magic.
Latency is simply delay — the time it takes for data to travel from one point to another and back. Picture shouting into a tunnel and waiting for the echo. Latency is how long you stand there before the answer comes back. On the web it is usually measured in milliseconds (thousandths of a second), and it determines how fast something feels to use.
It is important to distinguish latency from bandwidth. Bandwidth is how much data can move at once — like how wide the motorway is. Latency is how long the journey takes — like how far you have to drive. You can have a very wide motorway and still wait a long time if the destination is on the other side of the world. That is why an app can feel sluggish even on fast internet: the information simply has a distance to travel.
Low latency is what you notice when everything just flows — a button you press responds instantly, a page loads before you blink. High latency is that irritating little pause that makes everything feel laggy and slow.
Why is latency important for your business?
Latency affects how fast and professional your digital presence feels — and that affects whether visitors stay or click away. A sluggish website or checkout makes customers lose patience and leave, often without even thinking about why. Low latency is not just about technology; it is about keeping customers and revenue.
For services where speed matters — booking systems, e-commerce, logged-in portals — the difference between fast and slow can be the difference between a happy customer and a lost sale.
Latency in practice
Say you run an online shop and the server hosting the site is in the US. Every time a customer clicks, the request crosses the Atlantic and back — that adds latency and makes the site slower, even for your neighbour down the street. The fix is often to place content on servers closer to the customer, for example via a CDN (a network of servers spread geographically) so data has a shorter path to travel.
Another common example: a checkout that loads slowly at every step. The customer fills in details, waits, waits again — and abandons. Here you can often cut latency through smarter technology choices, and suddenly the whole purchase feels smooth.
Common questions about Latency
What does latency mean?
Latency is delay — the time it takes for data to travel between two points and back. It is usually measured in milliseconds. Low latency makes an app feel fast and responsive; high latency makes it laggy.
What is the difference between latency and bandwidth?
Bandwidth is how much data can move at once, like the width of a motorway. Latency is how long the journey takes. You can have fast internet (high bandwidth) and still experience delay if latency is high.
What is good latency?
Generally, latency under 100 milliseconds feels fast for the web, and under 50 milliseconds feels very good. What counts as good depends on the use case — games and real-time services need lower latency than a normal web page.
Related terms
Serverless
There are still servers — you just do not need to worry about them. Someone else has the headache. You have the app.
API
Application Programming Interface. Think of a waiter who takes your order (request) and brings the food (data) from the kitchen (server).
Cache
Stored data that loads instantly instead of being fetched again. Often the reason your site feels fast — or why changes do not show up.
CDN
Content Delivery Network — copies of your site spread around the world so it loads quickly wherever your visitors are.
Cloud
Someone else's computers. Servers in massive data centres you rent instead of own — AWS, Google Cloud, Azure.
Database
Where all your data lives — users, orders, everything. Lose the database and you lose everything, which is why we back it up.