Knowledge MaxxingError budget
An error budget is the amount of allowable failure implied by a service-level objective, such as the total downtime still permitted while still meeting a 99.9% target.
Prerequisite: Service-level objective
What matters
Thinking in terms of a budget reframes reliability as something to be spent deliberately, for example on releasing new features faster, rather than as a goal to maximize without limit.
Example
A 99.9% objective over a month implies roughly 43 minutes of allowed downtime, which is the team's error budget to spend or preserve for that period.
Common misconception
An error budget being 'spent' is not automatically a crisis; it's an expected, planned allowance that a team can choose how to use, not an emergency by default.
Recall question
What does an error budget represent relative to a service's stated objective?