# Performance monitoring and budgets — Web Performance Optimization

Source: https://www.skillbyai.com/en/web-performance/web-perf-21

> Set performance budgets and establish continuous monitoring to maintain performance standards.

## Setting performance budgets

Define limits: JavaScript <250KB gzipped, CSS <50KB, images <500KB, LCP <2.5s, INP <200ms. Tools: bundlesize, performancebudget.io. Fail CI/CD if budgets are exceeded to prevent regressions.

## Continuous performance monitoring

Use services: Vercel Analytics, Sentry, New Relic, Google Analytics 4 (Web Vitals). Track metrics over time. Set alerts for regressions. Monitor real user metrics across browsers, devices, regions. Correlate performance with conversion rates.

## Budget enforcement strategies

Automate checks in CI/CD pipeline. Use performance budgets as guardrails, not hard limits. Educate team on tradeoffs. Track budgets over time. Adjust budgets based on business goals and competitive analysis.

Quick check

**Quiz:** What is a reasonable JavaScript budget?

- [ ] <1MB uncompressed
- [x] <250KB gzipped
- [ ] >1MB is acceptable
- [ ] <10MB per page

*Answer:* <250KB gzipped. A gzipped JavaScript budget near 250KB keeps parse and execution time manageable.