---
title: "Heavy third-party footprint (perf/third-party-heavy)"
description: "perf/third-party-heavy: Third-party scripts (analytics, chat, tag managers, embeds) are outside your control and are a leading cause of long tasks and poor…"
canonical: https://void-design.vercel.app/rules/perf/third-party-heavy
lastModified: 2026-09-16
---

# Heavy third-party footprint

`perf/third-party-heavy` · severity **warn** · category Performance · detected by `void perf` and `void audit`

## Why it matters

Third-party scripts (analytics, chat, tag managers, embeds) are outside your control and are a leading cause of long tasks and poor INP.

## How to fix it

Remove unused tags, load the rest after interaction or idle (next/script lazyOnload), self-host critical ones, and use facades for embeds.

## More performance rules

`void perf` reports 25 rules in this category. Core Web Vitals and bytes: LCP, CLS, TBT, TTFB, JavaScript, CSS, fonts, images, caching and compression, measured as the median of several runs on a throttled mobile and a desktop profile.

- `images-missing-dimensions` Images without width/height or aspect-ratio — [perf/images-missing-dimensions](https://void-design.vercel.app/rules/perf/images-missing-dimensions)
- `render-blocking` Render-blocking resources delay first paint — [perf/render-blocking](https://void-design.vercel.app/rules/perf/render-blocking)
- `no-text-compression` Text resources are served uncompressed — [perf/no-text-compression](https://void-design.vercel.app/rules/perf/no-text-compression)
- `cache-headers` Hashed static assets are not cached long-term — [perf/cache-headers](https://void-design.vercel.app/rules/perf/cache-headers)
- `dom-size` DOM is very large — [perf/dom-size](https://void-design.vercel.app/rules/perf/dom-size)
- `bfcache-blocked` Page is not eligible for the back/forward cache — [perf/bfcache-blocked](https://void-design.vercel.app/rules/perf/bfcache-blocked)
- `lighthouse-score-low` Lighthouse performance score is low — [perf/lighthouse-score-low](https://void-design.vercel.app/rules/perf/lighthouse-score-low)
- `lighthouse-audit` Lighthouse flagged an opportunity — [perf/lighthouse-audit](https://void-design.vercel.app/rules/perf/lighthouse-audit)

Detected by `void perf` and `void audit`. Explain it in a terminal: `void rules perf/third-party-heavy`