Request memoization: is fetch Always Memoized or Only with force-cache in Next.js 15?

[Jancaster1234]

Summary

I’m looking for clarification on whether fetch requests are always memoized or if memoization only occurs when explicitly using force-cache in Next.js 15.

In this blog: https://nextjs.org/docs/app/building-your-application/data-fetching/fetching#reusing-data-across-multiple-functions
It states:
"If you are using fetch, requests can be memoized by adding cache: 'force-cache'. This means you can safely call the same URL with the same options, and only one request will be made."

In other blog: https://nextjs.org/docs/app/building-your-application/caching#request-memoization
An example suggests that fetch is automatically memoized, regardless of the cache setting:

async function getItem() {
// The fetch function is automatically memoized and the result
// is cached
const res = await fetch('https://.../item/1')
return res.json()
}

// This function is called twice, but only executed the first time
const item = await getItem() // cache MISS

// The second call could be anywhere in your route
const item = await getItem() // cache HIT

Additional information

No response

Example

No response

[icyJoseph]

Yeah, some documentation is not fully up-to-date, I think, but let's go off the Next 15 release notes:

With Next.js 15, we're changing the caching default for GET Route Handlers and the Client Router Cache from cached by default to uncached by default. If you want to retain the previous behavior, you can continue to opt-into caching.

[Jancaster1234]

Thanks! And yes, I know they changed the default caching mechanism in nextJS 15, but this doesn't answer my confusion about whether fetch requests are always memoized or if memoization only occurs when explicitly using force-cache. As it states in the doc, fetch requests can be [memoized] by adding cache: 'force-cache'. This makes me skeptical because I think React automatically memoizes a request regardless of the cache option. For more context, I have a page where a fetch request is called twice. I don't know if I need to add force-cache to ensure the request is memoized on this page.
Here is my code:

// src/app/hackathon/[id]/page.tsx

import { Metadata } from "next";
import { Hackathon } from "@/types/entities/hackathon"; // Import type

type HackathonProps = {
params: { id: string }; //Keep this to access the dynamic route param
};

// This function should be memoized to avoid fetching the same data multiple times
async function getHackathonData(id: string): Promise {
const res = await fetch(http://localhost:3000/api/hackathon/${id}, {
cache: "no-store",
});
if (!res.ok) throw new Error("Failed to fetch hackathon data");
return res.json();
}

export async function generateMetadata({
params,
}: HackathonProps): Promise {
// Await the params object
const id = (await params).id;
const hackathon = await getHackathonData(id);
return {
title: hackathon.name,
description: hackathon.description,
};
}

export default async function HackathonDetail({ params }: HackathonProps) {
// Await the params object
const id = (await params).id;
const hackathon = await getHackathonData(id);

return (

something

);
}