Performance budget enforced in build

Without an enforced performance budget, bundle size drifts upward with each feature addition. A new charting library here, a heavier date picker there — after six months, your initial bundle has grown from 200KB to 600KB with no single commit being obviously culpable. ISO 25010:2011 time-behaviour captures the gradual degradation; an enforced budget makes the growth visible immediately, when a single PR pushes past the threshold, rather than during a quarterly performance audit.

Add size-limit to your project and configure it with a 250KB threshold for the initial JavaScript bundle. Wire it into your CI pipeline so PRs fail if they exceed the budget.

// .size-limit.json
[
  {
    "path": ".next/static/chunks/pages/index-*.js",
    "limit": "250 KB",
    "gzip": true
  }
]

In package.json scripts: "size": "size-limit", then add npm run size to your CI workflow after npm run build.

• ID: performance-budget-enforced

• Severity: low

• What to look for: Count all build config files. Enumerate any bundle size budget settings (size-limit, webpack performance hints). Check build config for bundle size budget settings. Look for webpack-bundle-analyzer with size warnings, or tools like size-limit. Verify build fails if bundle exceeds budget.

• Pass criteria: Performance budget is defined (e.g., max bundle size 250KB) and enforced. Build fails if budget is exceeded. Budget documented in repo. At least 1 budget defined with maximum 250KB for the initial bundle.

• Fail criteria: No performance budget defined, or budget is not enforced (doesn't fail build).

• Skip (N/A) when: Never — budgets help prevent gradual performance degradation.

• Cross-reference: For Lighthouse CI enforcement in CI/CD, see lighthouse-ci-configured.

• Detail on fail: "No bundle size budget configured" or "Budget defined as 500KB but not enforced — build succeeds even if bundle grows to 750KB"

• Remediation: Configure size-limit or webpack bundle analyzer with budget enforcement.

  // .size-limit.json — enforce bundle budget
  [{ "path": ".next/static/chunks/*.js", "limit": "250 KB", "gzip": true }]