---
title: Edge Cache Purge Library
description: Learn how to use `@wpengine/edge-cache` library - an npm package that enables enables granular purging of your headless WordPress site's edge cache.
url: https://developers.wpengine.com/docs/headless-platform/additional-guides/edge-cache-purge-library/
image: https://developers.wpengine.com/og/docs/headless-platform/additional-guides/edge-cache-purge-library.png
---

# Edge Cache Purge Library

Previously, purging the edge cache for headless WordPress sites was only possible at the environment level, which meant clearing all cached content indiscriminately at the edge. While this approach ensured that content was refreshed, it also resulted in unnecessary purging of other assets, leading to inefficiencies.

WP Engine now provides a framework-agnostic npm package for purging the edge cache of your headless WordPress site at a granular level with `@wpengine/edge-cache`. Instead of purging the entire cache, you can execute the following:

- Purge individual pages by specifying their paths
- Purge groups of pages using custom cache tags

This package can be integrated into an API endpoint in your application, allowing selective edge cache purging triggered by various sources, such as WordPress plugins or hooks.

## Getting Started

### Installation

Install the package using npm

Terminal window

```shell
$ npm install --save @wpengine/edge-cache
```

### Package API

View the up to date package API on the npm site: <https://www.npmjs.com/package/@wpengine/edge-cache>

### Purge by Path

The following example will purge the paths `/foo` and `/bar` from the edge cache using `purgePaths`

```javascript
import { purgePaths } from '@wpengine/edge-cache';


try {
  const paths = ['/foo', '/bar'];
  await purgePaths(paths);
} catch (error) {
  console.error(error);
}
```

### Purge by Tag

Tags must first be added to the pages via the `Cache-Tag` response header. You can add multiple tags to a single page. For example:

```
Cache-Tag: foo,bar
Cache-Control: max-age=31536000
```

Now all pages with any one of the given tags can be purged using `purgeTags` like so:

```javascript
import { purgeTags } from '@wpengine/edge-cache';


try {
  const tags = ['foo', 'bar'];
  await purgeTags(tags);
} catch (error) {
  console.error(error);
}
```

> **Note**
>
> While `Cache-Tag` headers are used internally for cache management, they are not visible in browser network inspections. This is normal and does not affect the purging functionality.

## Limitations

### Running outside of the Headless Platform

Pages and tags can only be purged while your app is running on our platform. If your code is running locally or on another platform, a message will be logged instead.

### Supported versions of npm and Node.js

Make sure you’re using versions of npm and Node.js that are supported by our Headless Platform. You can check the currently supported versions [here](https://developers.wpengine.com/docs/headless-platform/platform-guides/customizing-builds/#nodejs).

### Functional Limitations

1. A maximum of 30 tags can be purged at once.
2. Edge cache purging is subject to rate limiting. Each environment is allocated 300 purge operations per hour. This limit may be adjusted in the future based on usage patterns. Note that purging multiple paths in a single API call counts as one operation against this limit.
3. Wildcards and other operators are not supported. If you require multiple paths to be purged, you must first add cache tags to the pages and then purge by tag.
4. This package only purges the Node.js edge cache, not the WordPress edge cache.

> **Caution**
>
> Due to rate limiting, add authentication to any edge cache purge endpoint.

### Debugging

To debug, add the `HEADLESS_EDGE_CACHE_DEBUG=true` environment variable and rebuild your environment - the following logs will be output:

```
EdgeCache: DEBUG: Purged edge cache for paths: (...)
```

## Was this helpful?

Thanks for the feedback!

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