The Misleading Documentation

Oct 13, 2025 by wbrum.org 141 views

Revalidating Tags in Next.js: Understanding the Documentation Issue

As developers, we rely on accurate and comprehensive documentation to ensure we're using a framework or library to its full potential. However, sometimes, even the best documentation can be misleading or incomplete. In this article, we'll explore a specific issue with the documentation for revalidateTag in Next.js, a popular React-based framework for building server-side rendered (SSR) and statically generated websites.

What is the Documentation Issue?

The issue at hand is that the main API reference for revalidateTag in Next.js documentation does not accurately describe its behavior. Specifically, it states that revalidateTag only invalidates the cache when the path is next visited, which can lead to a misunderstanding of how revalidation works in Next.js. This is particularly problematic when using staleTimes, as a single revalidation of any path or tag can cause all cached pages to refetch their data when visited, instead of the default layouts.

The Misleading Documentation

The main API reference for revalidateTag can be found here. However, upon closer inspection, it becomes clear that the documentation is incomplete and misleading. The relevant section reads:

revalidateTag only invalidates the cache when the path is next visited. This means calling revalidateTag with a dynamic route segment will not immediately trigger many revalidations at once. The invalidation only happens when the path is next visited.

This statement is misleading because it implies that revalidateTag only invalidates the cache when the path is next visited, which is not the case. In reality, calling revalidateTag from an action will invalidate the router cache and re-render the current route, regardless of the tag.

Context and Similar Behavior

To understand the issue better, let's look at the API reference for revalidatePath, which already discloses similar behavior:

Currently, revalidatePath invalidates all the routes in the client-side Router Cache when used in a server action. This behavior is temporary and will be updated in the future to apply only to the specific path.

This behavior is similar to what we're seeing with revalidateTag, and it's essential to include this information in the revalidateTag documentation to avoid confusion.

Is There Any Context That Might Help Us Understand?

Yes, there is context that can help us understand the issue better. The caching section of the Next.js documentation provides valuable information on how caching works in Next.js, including the client-side router cache. Understanding this context is crucial to grasping the behavior of revalidateTag and its impact on caching.

Does the Docs Page Already Exist? Please Link to It.

Yes, the docs page for revalidateTag already exists, and it can be found here. However, as we've discussed, the documentation is incomplete and misleading, which is the primary issue we're addressing in this article.

In conclusion, the documentation for revalidateTag in Next.js is incomplete and misleading, which can lead to a misunderstanding of how revalidation works in Next.js. By including similar behavior to revalidatePath and providing context on caching, we can ensure that developers have a clear understanding of how revalidateTag works and can use it effectively in their applications.

Based on our analysis, we recommend the following changes to the revalidateTag documentation:

Add a clear description of the behavior: Include a clear and concise description of how revalidateTag works, including its impact on caching.
Provide context on caching: Include information on how caching works in Next.js, including the client-side router cache, to help developers understand the behavior of revalidateTag.
Similar behavior to revalidatePath: Include a note on the similar behavior to revalidatePath to help developers understand the implications of using revalidateTag.

By making these changes, we can ensure that developers have a clear understanding of how revalidateTag works and can use it effectively in their applications.
Revalidating Tags in Next.js: A Q&A Guide

In our previous article, we explored the documentation issue with revalidateTag in Next.js and discussed the importance of accurate and comprehensive documentation. In this article, we'll provide a Q&A guide to help developers understand the behavior of revalidateTag and its impact on caching.

Q: What is `revalidateTag` in Next.js?

A: revalidateTag is a function in Next.js that allows you to invalidate the cache for a specific tag. When you call revalidateTag, it will invalidate the cache for the specified tag and re-render the current route.

Q: What is the difference between `revalidateTag` and `revalidatePath`?

A: revalidatePath and revalidateTag both invalidate the cache, but they have different behaviors. revalidatePath invalidates the cache for a specific path, while revalidateTag invalidates the cache for a specific tag. This means that revalidateTag will invalidate the cache for all pages that use the specified tag, while revalidatePath will only invalidate the cache for the specific path.

Q: What is the impact of `revalidateTag` on caching?

A: When you call revalidateTag, it will invalidate the cache for the specified tag and re-render the current route. This means that all pages that use the specified tag will be re-rendered, and their cache will be invalidated. This can have a significant impact on performance, especially if you have a large number of pages that use the same tag.

Q: How does `revalidateTag` interact with `staleTimes`?

A: revalidateTag and staleTimes interact in a way that can be counterintuitive. When you call revalidateTag, it will invalidate the cache for the specified tag and re-render the current route. However, if you have set a staleTime for the page, it will not be re-rendered immediately. Instead, it will be re-rendered when the page is next visited, and the cache will be invalidated.

Q: What are the implications of using `revalidateTag` with `staleTimes`?

A: Using revalidateTag with staleTimes can have significant implications for performance. When you call revalidateTag, it will invalidate the cache for the specified tag and re-render the current route. However, if you have set a staleTime for the page, it will not be re-rendered immediately. Instead, it will be re-rendered when the page is next visited, and the cache will be invalidated. This can lead to a situation where all pages that use the same tag are re-rendered simultaneously, which can have a significant impact on performance.

Q: How can I avoid the implications of using `revalidateTag` with `staleTimes`?

A: To avoid the implications of using revalidateTag with staleTimes, you can use a combination of revalidateTag and revalidatePath. By using revalidatePath to invalidate the cache for a specific path, you can avoid the implications of using revalidateTag with staleTimes.

Q: What are the best practices for using `revalidateTag`?

A: The best practices for using revalidateTag are:

Use revalidateTag sparingly, as it can have a significant impact on performance.
Use revalidatePath to invalidate the cache for a specific path, rather than using revalidateTag.
Set a staleTime for pages that use the same tag to avoid re-rendering all pages simultaneously.
Use a combination of revalidateTag and revalidatePath to avoid the implications of using revalidateTag with staleTimes.

By following these best practices, you can use revalidateTag effectively and avoid the implications of using it with staleTimes.