---
url: https://void.cloud/guide/edge/prerendering.md
description: Prerender pages at deploy time so the first visitor receives cached HTML.
---

# Edge Prerendering

Prerender pages at deploy time so the first visitor receives cached HTML.

* [Markdown pages](../pages-routing/markdown.md) are auto-prerendered.
* [Island pages](../pages-routing/islands) with no companion loader and no dynamic params are also auto-prerendered.

## Static pages (no params)

Export `prerender = true` from the companion `.server.ts` file:

```ts
// pages/about.server.ts
export const prerender = true;
```

Pages without dynamic params do not need `getPrerenderPaths()`.

## Dynamic pages (with params)

For pages with URL params, also export `getPrerenderPaths()` to specify which param combinations to prerender. Annotate the return type with [`PageParams`](../../reference/api/types.md#route-types) for that page's URL pattern, such as `/blog/:slug` for `pages/blog/[slug].server.ts`. TypeScript then requires each object to include those params, so a missing or misspelled key is a type error. Void does not infer this type from the filename.

```ts
// pages/blog/[slug].server.ts
import type { PageParams } from 'void/routes';

export const prerender = true;

export async function getPrerenderPaths(): Promise<PageParams<'/blog/:slug'>[]> {
  return [{ slug: 'hello-world' }, { slug: 'getting-started' }];
}
```

Each object must include every param in the page path. Values can be strings or numbers, and Void URL-encodes them. A single-segment param such as `[slug]` cannot contain `/`. For nested paths, use a catch-all page such as `pages/docs/[...slug]` and return `{ slug: 'guides/intro' }`. If an entry is invalid, `void deploy` fails. The error names the server file and the entry index.

## Custom SSR

In custom SSR mode (`src/main.ssr.ts`), export `getPrerenderPaths()` at the top level. Since there's no file-based routing, return full path strings:

```ts
// src/main.ssr.ts
export const prerender = true;

export async function getPrerenderPaths(): Promise<string[]> {
  return ['/', '/about', '/blog/hello-world'];
}
```

Annotate this return type as an array of path strings. Use `PageParams` on file-based pages, where the function returns param objects.

## Relationship to revalidation

Setting `routing.isr: false` in `void.config.ts` disables ISR and this edge-prerendering behavior, including per-page exports. It does not disable build-time HTML generation with `output: "static"`.

Prerendered pages default to a one-year revalidate TTL. Deploys clear the ISR cache.

Override the TTL per page:

```ts
// pages/about.server.ts
export const prerender = true;
export const revalidate = 3600;
```

If the cached page expires before your next deploy, the next request waits for a fresh render.

## Behavior details

* Prerender happens once per deployment, before traffic is routed to the new version. Prerendered pages are cached at the edge.
* Only paths with a positive revalidate TTL are prerendered (TTL `0` is skipped).
* Prerender failures are logged but never block the deploy. The page will render on the first request as usual.