What is an Error Budget?
⚡
Quick Answer
An error budget is the allowed amount of unreliability — the gap between 100% and your SLO (e.g., a 99.9% SLO allows ~43 minutes of downtime per month). It is the budget of risk you can spend on change.
Detailed Answer
Error budgets turn reliability into a shared decision tool: if the budget is healthy, teams ship faster and take more risk; if it is exhausted, they freeze risky changes and focus on stability. This aligns dev (velocity) and ops (reliability) around one objective number instead of arguing.
💡
Interview Tip
Explain how the budget arbitrates velocity vs stability — that operational use is the point interviewers want.
error-budgetslosre