Lingua-e
← Glossary

What does "side effect" mean in programming?

side effect is one of the most common terms in software development. This guide explains what it means, how it is used in practice, and why it matters, with real examples from the developer world.

Definition

Any operation a function performs beyond returning a value: writing to a database, modifying a variable outside its scope, logging to the console, or making a network request. Side effects make code harder to test and reason about. Functional programming aims to isolate side effects.

Example

"That function has a side effect: it modifies the global config object. That is why the test environment is leaking state."

Can you put this sentence in the right order?

Tap the words to place them here

Keep building your technical English

You just looked up what this word means. Lingua-e turns vocabulary like this into full practice: fill-in-the-blanks, listening, and real developer conversations.

Practice this for free

Related terms

Was this page helpful?