Glossary

Error budget

The amount of unreliability an SLO allows over a period: with a 99.9% target, 0.1% of requests may fail. Spending it slows releases; saving it allows risk.

SLO
Service level objective: a target value or range for an SLI, such as 99.9% of requests succeeding over 30 days.
SLI
Service level indicator: a carefully defined quantitative measure of some aspect of service, such as the share of requests served successfully.

Sources

Google SRE book, ch. 3: Embracing Risk

Updated October 22, 2026.

Free for you and one backup · 3 apps · no card

Sleep through the small stuff.

Run one command in your repo. Pagerless shows every change before it makes it.

npx pagerless connect

Start free How it works

Error budget

Related terms

SLO

SLI

Sleep through the small stuff.