FAQ
Common questions about prerendering, JavaScript SEO, and rendering choices
This page works best as a fast answer layer. Use it when the team has a narrow question and needs a direct explanation without reading a full guide first.
If the FAQ answer points to a bigger decision, jump into technology, guides, or use cases. The FAQ should reduce ambiguity, not replace the canonical paths.
Most FAQ questions belong to one of three bigger intent clusters
Use these paths when the short answer turns into a broader implementation or architecture decision.
Architecture and rendering model
Use this path when the real question is prerendering versus SSR, what dynamic rendering actually means, or whether the architecture choice is even right.
Compare pre-rendering vs SSROperational SEO bottlenecks
Go here if the question behind the FAQ is really about crawl waste, stale cache, weak recrawl, or scaling the rendering layer in production.
Open the operations guidesVertical implementation patterns
Choose this path if the same question behaves differently on SaaS docs, ecommerce catalogs, stale listings, bookings, or marketplace facets.
Browse use cases by industryFrequently Asked Questions
Common questions about rendering, prerender, and JavaScript SEO — answered by our engineering team.
Pre-rendering generates static HTML snapshots of each URL ahead of time and serves them from a cache. SSR rebuilds HTML on every request on the origin server. Pre-rendering avoids runtime CPU on your app servers and is framework-independent; SSR ties rendering into framework internals and pays CPU on every request.
No, provided bots and users receive substantially the same content. Cloaking means serving materially different content to manipulate rankings. Pre-rendered HTML that mirrors the user-facing DOM is an accepted technique documented by Google.
Yes for JavaScript-heavy sites. Googlebot queues JavaScript execution behind an HTML crawl; deferred indexing can lag the first crawl by hours to weeks. Bing, Yandex, and most AI crawlers have weaker JavaScript execution than Googlebot. Pre-rendering closes the gap.
Cost is driven by unique URL count, re-render frequency, and cache TTL. ostr.io uses usage-based tiers starting below $50/month for sites under 10,000 URLs. Self-hosted headless Chrome infrastructure typically costs 3-5x more once CPU, RAM, and operational burden are modelled.
Pre-rendering is framework-agnostic because it consumes the rendered DOM, not source code. React, Vue, Svelte, Angular, Next.js, Nuxt, SvelteKit, Astro, Remix, and vanilla JavaScript SPAs all work. Integration is via an edge middleware, reverse proxy, or CDN worker that detects crawlers and serves cached HTML.
Cache-Control headers and event-driven invalidation govern freshness. ostr.io refreshes every URL on a configurable TTL (default 1 day) and exposes a purge API for immediate invalidation on content updates. Stale snapshots risk indexing old price, availability, or headline data.
Yes. Bot-detection middleware (matching user-agent and reverse DNS) routes crawler traffic to cached HTML while users continue to receive the client-rendered SPA. This is the standard dynamic-rendering pattern.
Use the FAQ to narrow the question, then move back to the main cluster
That keeps the site structured: quick answers live here, deeper diagnosis and implementation live in the canonical hubs.
Related pages for questions that need more context
These pages sit next to the FAQ and help when the answer is no longer short or purely definitional.
About
Use this when the question is about scope, methodology, editorial boundaries, or how prerender.info verifies claims.
About prerender.infoBlog
Use this for narrower commentary and examples that support the main architecture, guide, and use-case clusters.
Open the blogAdvanced guides
Use these only when the short answer turns into a real edge case such as hydration failures or paywall parity.
Open advanced guidesEditorial trust
Written by ostr.io engineering team · Engineering Team. We build and run pre-rendering infrastructure for more than 200 engineering teams, which is where the numbers and code samples on this page come from.
Last updated . Editorial scope and review policy: About prerender.info.