There is no ISR on Cloudflare
ISR means incremental static regeneration: storing generated content and refreshing it later. A Cloudflare Worker runs request-handling code. Its entrypoint is where that code starts.¶
There is no SvelteKit isr switch for the Cloudflare adapter. That configuration belongs to adapter-vercel.¶
Vercel ISR stores generated content and regenerates it. Kit #661 asks for a general regeneration feature.¶
Cloudflare can still cache rendered pages.¶
Workers Cache puts a cache in front of a Worker entrypoint. Its stale-while-revalidate behavior serves a stale response while the Worker refreshes it.¶
What our comparison proves
We compare three local candidates:¶
The cache candidate creates a marker inside the rendering entrypoint. Repeated identical requests do not reuse it.¶
An assets response carries CF-Cache-Status: HIT. That proves only asset-cache reuse. The selected Miniflare implementation does not implement Workers Cache handling.¶
The cache candidate’s home-page Markdown timings are:¶
| Request | Local time |
|---|---|
| Cold: first application request in a fresh runtime | 8.25 ms |
| Warm: median of 20 sequential requests | 1.69 ms |
Neither number measures reuse of a cached response in Cloudflare’s data centers (HIT).¶
The check does not prove:¶
- Stale-while-revalidate.¶
- Purge.¶
- Separate caching for HTML and Markdown responses across Workers Cache HITs.¶
The accepted configuration leaves cache behavior unproven.¶
What we choose
We choose static assets. apps/site/src/static-assets.ts serves separate HTML and Markdown assets. The dynamic signup page stays outside that path.¶
See Worker init runs twice8 for another boundary a local check can miss.¶
Sources
- SvelteKit Vercel adapter. Primary source. SvelteKit Vercel adapter Accessed 2026-10-02.
- Vercel ISR. Primary source. Vercel ISR Accessed 2026-10-02.
- Add incremental static regeneration. GitHub. Add incremental static regeneration Accessed 2026-10-02.
- Workers Cache announcement. Primary source. Workers Cache announcement Accessed 2026-10-02.
- Workers Cache documentation. Primary source. Workers Cache documentation Accessed 2026-10-02.
- apps/site/src/static-assets.ts. GitHub. apps/site/src/static-assets.ts Accessed 2026-10-02.
- Serve static assets through Effect HTTP composition. GitHub. Serve static assets through Effect HTTP composition Accessed 2026-10-02.
Last changed 2026-10-10 in 978dccc. Source on GitHub. Change log.
Linked from
- Agent guide. An Effect stack so pure (aspirational) Kit Langton will blush.
There is no ISR on Cloudflare — SvelteKit’s Vercel ISR setting does not configure Workers Cache; our local comparison did not prove cache reuse.
- Change log. What changed in the files served here, newest first.
There is no ISR on Cloudflare — edited: docs: point live docs, skills and Brain pages at apps/site
- Full agent guide. An Effect stack so pure (aspirational) Kit Langton will blush.
- Rat Stack lore | rat-stack. Short, source-grounded notes on the ideas and decisions behind rat-stack.
There is no ISR on Cloudflare — SvelteKit’s Vercel ISR setting does not configure Workers Cache; our local comparison did not prove cache reuse.
- Source change history (log.md). The generated change log as Markdown.
There is no ISR on Cloudflare — edited: docs: point live docs, skills and Brain pages at apps/site