Routing & SSR: Prerendering a component in an SSR page

Join the AI Workshop to learn more about AI and how it can be applied to web development. Next cohort February 1st, 2026

The AI-first Web Development BOOTCAMP cohort starts February 24th, 2026. 10 weeks of intensive training and hands-on projects.


I had a server-rendered Astro page and I was doing a quite intensive calculation on it. It ran on every page load.

So I used a partial (new in Astro 3.4) and set the prerender flag on it:

---
export const prerender = true
export const partial = true
---

Then I included this partial client-side using HTMX (you could also just use a fetch() request and swap some innerHTML too).

Lessons in this unit:

0: Introduction
1: Dynamic routing
2: SSR in Astro
3: API endpoints in Astro
4: ▶︎ Prerendering a component in an SSR page
5: Set cookie and redirect
6: Render different HTML based on HTTP method
7: Decide to render a partial or not dynamically in Astro
8: Fetching data from the network