Prerender SPA pages for bots
npm install fastify-prerender-plugin
> Build your SPA. Get SEO for free.
>
> Stop choosing between SPAs and SSR. This Fastify plugin automatically detects bots and serves them fully-rendered HTML—while your users get the fast SPA experience they deserve. No refactoring. No complexity. Just add one plugin.
You want to ship fast SPAs. Google wants fully-rendered HTML. Traditional SSR means maintaining two codebases or dealing with complex frameworks.
This plugin solves that. Write your SPA once, and bots automatically get server-rendered snapshots using Lightpanda—a blazingly fast, lightweight headless browser built for SSR.
✨ Zero impact on your users • ⚡ Lightning-fast setup • 🧠 Smart bot detection • 💾 Minimal memory footprint
``sh`
pnpm install fastify-prerender-plugin
Requirements: Node.js 22+, Fastify
Register the plugin with your Fastify server. That's it.
`typescript
import { fastify } from 'fastify'
import { prerenderPlugin } from 'fastify-prerender-plugin'
const app = fastify()
await app.register(prerenderPlugin, {
urls: ['/'], // URLs to prerender (supports regex too!)
port: 3000
})
app.get('/', (request, reply) => {
reply.type('text/html').send(
)
})app.listen({ port: 3000 })
`Done! Bots now get fully-rendered HTML. Your users get the lightning-fast SPA.
Configuration
typescript
{
urls: ['/', /^\/about/], // URLs to prerender (strings or regex)
host: 'localhost', // Optional, defaults to 'localhost'
port: 3000 // Your Fastify server port
}
`How It Works
1. Request comes in → Plugin checks
with isbot
2. Bot detected? → Lightpanda renders the page in milliseconds
3. Fully-rendered HTML → Cached (5 min) and served to bot
4. Regular user? → Standard SPA, zero overheadYour SPA works exactly as before. Bots see the rendered version. Everyone wins.
About Lightpanda
This plugin uses Lightpanda—a lightweight headless browser built specifically for SSR. It's dramatically lighter than Chromium or Firefox, starts instantly, and installs automatically with the plugin.
Custom executable path? Set
LIGHTPANDA_EXECUTABLE_PATH:`sh
export LIGHTPANDA_EXECUTABLE_PATH=/path/to/lightpanda
``Issues and PRs welcome! Open an issue or submit a pull request.
MIT