---
type: Glossary Term
title: "Prerendering"
description: "Generating static HTML snapshots of JavaScript-rendered routes for crawlers and (sometimes) users."
resource: "https://prerendering.com/glossary/prerendering"
tags: [rendering, glossary]
timestamp: 2026-05-11T00:00:00Z
---

# Prerendering

Generating static HTML snapshots of JavaScript-rendered routes for crawlers and (sometimes) users.

Prerendering closes the gap between a JavaScript-rendered application and crawler-facing HTML. A prerender service runs the page in a headless browser, captures the fully rendered HTML, and serves it from cache. Used to make SPAs and JS-heavy SSR sites reliably indexable by search and AI crawlers without rewriting the rendering pipeline.

## When it matters

- Single-page applications (React, Vue, Svelte) where the initial HTML is empty until JS executes.
- Server-rendered sites where the server-rendered HTML still depends on client-side hydration for visible content.
- Sites that need to serve different (faster, cached) HTML to bots than to humans, without cloaking.
- Teams that cannot afford a full SSR/SSG rewrite but need crawler-reliable HTML in weeks, not quarters.

## Common pitfalls

- Caching prerendered HTML too aggressively, so updates take hours or days to reach crawlers.
- Routing only Googlebot through prerender while leaving GPTBot, ClaudeBot, and PerplexityBot on the JS-only path.
- Returning a prerendered HTTP 200 for soft-404 routes, which inflates the indexable surface with empty pages.
- Forgetting to keep `<link rel="canonical">` and JSON-LD consistent between prerendered HTML and the runtime client view.

## How to verify

- curl -A "Googlebot" https://your-site.com/route — the response body must contain visible text and primary entities, not a JS bootstrap stub.
- Compare prerendered DOM vs runtime DOM via headless Chrome to confirm semantic parity (avoid cloaking risk).
- Search Console URL Inspection — "Rendered HTML" must match what prerender returns, including structured data.
- Server logs — Googlebot, GPTBot, OAI-SearchBot must show 200 responses from the prerender path, not from the JS bundle.

## External references

- [Google: Rendering on the web (web.dev)](https://web.dev/articles/rendering-on-the-web)
- [Google: Understand the JavaScript SEO basics](https://developers.google.com/search/docs/crawling-indexing/javascript/javascript-seo-basics)

## Related

- [Prerendering for Technical SEO and AI Visibility](/blog/prerendering-for-technical-seo.md)
- [Prerendering vs SSR vs SSG: 2026 Decision Guide](/blog/prerendering-vs-ssr-vs-ssg-decision-guide.md)