What does idempotent mean?
Idempotent is a technical adjective for an operation, function, or action that can be repeated without producing an additional effect. In other words, applying an idempotent operation once, twice, or many times leaves the system in the same state as applying it once. The term is especially important in computing, where it describes safe network requests, database operations, and transformations that can be retried without creating duplicate records. It is also used in mathematics for functions or transformations that remain unchanged when composed with themselves. Idempotence is a desirable property when software must handle unreliable networks, retries, or repeated user actions. Although the word is specialized, the underlying idea is straightforward: doing the same thing again does not make things go further. It should not be confused with identical, which describes two things as being the same, or immutable, which describes something that cannot change.
adjectiveDenoting an operation or action that can be applied repeatedly without changing the result beyond its first application. In computing and mathematics, an idempotent operation has the same effect whether it is performed once or many times.
- Relating to an operation or action that can be repeated one or more times with the same result as the first application.
- Relating to a mathematical function or transformation whose composition with itself is equal to the function itself.
"The request is idempotent, so retrying it after a network failure will not create duplicate records."
"The developer designed the endpoint to be idempotent, allowing clients to retry it safely."
"For an idempotent function, applying the function twice gives the same result as applying it once."
An idempotent operation is the computing equivalent of a reset button: pressing it again changes nothing.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does idempotent come from?
The word combines Latin idem, meaning “the same,” with Latin potent, meaning “powerful” or “having power.” It was developed in English for mathematical and computational contexts to describe operations whose repetition does not alter the result. Its Latin relatives include identical and identity, which also derive from idem.
Related word forms
How idempotent is actually used
The term is primarily used in computing, mathematics, and systems engineering. It describes a property of an operation, function, or transformation rather than of an ordinary physical action.
Easily confused with idempotent
Identical means exactly the same, whereas idempotent describes an operation that can be repeated without changing the result.
Immutable means unable to change, whereas idempotent means repeated application produces the same result.