Route handlers are running during build (cacheComponents)

[arjunkomath]

After I enabled cacheComponents with Next 16, I noticed that all my GET routes are running during build time. How do I disable this?

[dieguezz]

Hello. This is a common point of confusion, and you are correct: your GET routes are still running at build time.

That "runtime by default" behavior only applies to your UI (Pages and Layouts), not to your Route Handlers (route.js files). Your GET routes remain static by default, which is why you see them running at build time.

To fix this and force your GET routes to run at runtime (on every request), you must explicitly opt-out of static generation.

As the documentation for Route Segment Config states (https://nextjs.org/docs/app/api-reference/file-conventions/route-segment-config#dynamic), you need to add this line to the top of your route.js file:

export const dynamic = 'force-dynamic';

// Your GET function will now run at runtime
export async function GET(request) {
  // ...
}

This will solve the problem and ensure your routes are executed on request, not at build time.

[arjunkomath]

@dieguezz I've cacheComponents enabled, and force-dynamic is not supported. Its mentioned in the docs also, FYI https://nextjs.org/docs/app/getting-started/cache-components#effect-on-route-segment-config

Here is the error:

[icyJoseph]

Yeah in Next 15 this changed... but w/ 16 + cache components looks like I overlooked this detail in the docs 🤦

[dieguezz]

You are right, i'm sorry. BTW, do you have the "use cache" directive on top of the file? If so, i guess the solution is just to remove it.

[arjunkomath]

No worries. I had checked that, use cache is only in server components, I don't have it any of the route handlers.

[dieguezz]

But i mean in the component which is consuming this api. AFAIK your route is fine.

[arjunkomath]

Yep, checked that also. The problem is that I've some routes which are cron jobs that are not used anywhere else.

But these cron endpoints run during build which messes up the app.

[dieguezz]

Oh, i get it now. Maybe this is a bit ugly, but might help:
What if you check if build is running to just return something else instead of running the cron job?
You can check phases here

Add something like

if (process.env.NEXT_PHASE === PHASE_PRODUCTION_BUILD) return ...

[arjunkomath]

Thats a bit janky, for the time being I'm calling await headers(), this forces everything to be dynamic.

[apostolos]

Since GET requests are eligible for pre-renderingwhatever, you can easily opt out of that with connection:

import { connection, type NextRequest } from 'next/server';

export async function GET(req: NextRequest) {
  await connection();
  // ...
}

During the build step the GET function is still going to be called, so make sure you call await connection early. The best place to do it is right before introducing any side-effects (or doing dynamic IO) so the rest is still verified during build.

[arjunkomath]

Perfect, thank you!

[icyJoseph]

I overlooked this in the docs though - https://github.com/vercel/next.js/blob/canary/test/e2e/app-dir/cache-components/cache-components.routes.test.ts I'll have an update on Monday - just gonna double check w/ team too.