Cache Tags for eCommerce: Surgical invalidation, and then some

Posted on July 3rd, 2025
by Ronak Ganatra

TL;DR

Cache tags in DatoCMS let you selectively and surgically invalidate content, instead of blowing up your entire CDN cache on every content update. For eCommerce projects on headless sites, that means faster performance, fresher content, lower infrastructure costs, and a much better experience for both developers and users. Whether you're using DatoCMS for product content, or have a PIM in place and keeping the CMS just for landing pages and blogs, lets check out how cache tags come in to play.

Quick resources to get started:

The Performance v. Freshness Problem

eCommerce sites are dynamic by nature. Shoes go out of stock. Skateboards go on sale. BFCM rolls into town and the discounts rain down.

Non-promotional content changes constantly as well: product descriptions, CRM banners, price callouts, category intros, blog posts, AB Tests... we could go on. Most of this doesn’t justify a global cache purge or a full rebuild, but that’s still how many teams handle updates. As a result, users either get stale content or slower sites. Or worse. False information.

And aside from all that, it's just really expensive.

You can’t afford either. Performance erodes conversion. Staleness erodes trust. Rebuilds and cache purges erode your wallet.

The solution is surgical: only invalidate what actually changed. That’s why we build cache tags after all, to solve that exact problem for us.

What exactly are Cache Tags

Cache tags are lightweight string identifiers automatically included in the HTTP response headers when you query content from the CDA. They map to specific records in your project, be it a banner, a post, a product, whatever.

Query a product? You might get something like:

HTTP/1.1 200 OK

...

X-Cache-Tags: XXXX XXXX XXXX XXXX XXXX XXXX

{

"data": {

"product": {

"title": "Pink Lace-up Boots",

"inStock": "Y",

"_createdAt": "2025-06-01T15:19:24+01:00"

}

}

}

When any of those records update (via publishing or API), you can call the Admin API to purge juuuust those tags rather than the cache of the project or that content type:

curl -X POST https://site-api.datocms.com/cache/purge \
  -H "Authorization: Bearer YOUR_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{ "tags": ["XXXX XXXX XXXX XXXX XXXX XXXX", "YYYY YYYY..."] }'

That invalidates only the record/content that depends on those records. If you’re caching entire page responses or relying on ISR/SSG, that can dramatically reduce build and invalidation overheads.

When your CMS is your PIM

Some eCom sites use DatoCMS as the main content layer for products, collections, promos, and campaigns. This is a straightforward solution for many storefronts with small-to-medium sized catlogs who don't need a full-blown PIM to handle their inventory.

In this setup, cache tags let you invalidate cache based on what changed across your storefront. For example:

  • A single product update invalidates the cache for any corresponding product page(s) and any categories it's part of.
  • A promo ends and its banner is unpublished. Only the affected homepage sections are invalidated and rebuilt.
  • A category description is updated. That collection page is rebuilt or revalidated.

This saves infrastructure costs, because you’re not regenerating or purging unaffected pages. It also improves time-to-freshness. Most updates can reflect within seconds (or faster) without needing a full redeploy.

It also makes it possible to ship changes faster. Editors can publish without triggering full rebuild workflows or waiting for engineering. Devs don’t need to write cache logic from scratch or debug stale content reports.

When your PIM is your PIM

OK but what if you're a much bigger brand and you've got 1000s upon 1000s of products managed from the PIM. That's the source of truth right? So why care about the cache on CMS content as much?

Cache tags still matter here.

Even if your PDPs pull stock and pricing from your PIM, they may still render dynamic modules (badges, cross-sells, promo blocks) from DatoCMS. When that content changes, cache tags give you a direct way to invalidate only the relevant cache.

Cache Tags and DX

For developers, cache tags bring predictability and control.

First, they’re transparently exposed in every response. You can inspect them in your logs or edge functions and map cache tags to pages or components. That gives you a clear dependency graph for purge operations every time.

Second, they integrate well with most frameworks. In Next.js, for instance, you can build ISR fallback logic that listens to Dato webhook payloads and revalidates paths based on updated tag IDs.

But what about the content team?

The editorial team mostly won't (and actually shouldn't) be interacting with cache tags DIRECTLY, but they have also simplified how we handle preview content workflows. In setups where editors expect to preview content before publishing, cache tags allow the frontend to bypass stale caches without introducing complex logic or rebuild pipelines.

This creates a much smoother editor experience. Content teams can confidently publish or tweak components knowing that previews are fresh and production reflects changes really quickly. From a dev perspective, it removes an entire class of hard-to-debug issues around preview staleness.

OK but let's talk $$$

Every cache miss costs time and money. Every full rebuild increases infra cost. Revalidating 300 pages because one changed is wasteful on all fronts.

Cache tags give you a way to avoid that by making content invalidation proportional to actual change.

This might be hard to see for small projects, but matters more at scale. If you’re a retailer with hundreds of landing pages or localized content in multiple markets, the cost difference adds up fast. With cache tags, a change to a single DE promo page doesn’t need to touch your EN, FR, or ES versions. Your builds stay fast and scoped.

And freshness improves. Instead of waiting 5-10 minutes for a deploy pipeline to complete, you can push updated content live in seconds. Your editors don't have to wait to see their changes live, they can continue with their workflows uninterrupted.

Cache tags aren’t just a nice-to-have, they’re a critical tool for keeping content-driven eCommerce sites fast, fresh, and cost-effective. If you’re using DatoCMS in any capacity, wire in cache tag-based invalidation. It takes an afternoon to implement and saves you countless hours in edge cases, rebuilds, and support.