the.com/idempotence
do it once, do it a thousand times, get the exact same result — no bruises, no side effects.
means an operation that produces the same outcome no matter how many times you apply it, so repeating it changes nothing further.
from from latin idem (same) plus potence (power) — coined in 1870 by mathematician benjamin peirce while classifying algebraic laws, later smuggled into computer science by engineers tired of servers double-charging people.
math examplemultiplying by zero, forever, stays zero
web standardhttp put is meant to be idempotent, get too
real dangernon-idempotent retries caused actual duplicate bank charges
delete counts toodeleting an already-deleted item changes nothing further