How Do You Build a Webflow CMS Tag Filter Without Finsweet Plus or a Custom Backend in 2026?

Why Did I Stop Recommending Finsweet CMS Filter for Tag Filters in 2026?

For years, when a Webflow client wanted a working tag filter on their CMS blog, I dropped in Finsweet's CMS Filter attribute and called it a day. It worked, it was free for the basic tier, and the team behind it shipped reliable updates. Then in late February 2026, Finsweet quietly moved their advanced filtering features into a paid Plus tier at 24 dollars per month per site. Several clients pushed back on the cost for a single feature, and I started looking at alternatives.

The Finsweet Plus pricing is fair and the team deserves the revenue. But for a small founder site that just needs a working tag filter on a 60 post blog, 24 dollars a month feels heavy. I built a CSS plus light JavaScript approach that does exactly what most clients need without a paid attribute or a custom backend. Total time to implement is about 90 minutes if you know Webflow, less if you copy the code below.

This tutorial walks through the approach end to end. It covers the CMS structure I use, the HTML scaffolding inside Webflow Designer, the small JavaScript snippet that runs the filter, performance numbers from real client sites, and the limits where Finsweet or a custom backend still wins.

What Should the CMS Structure Look Like Before You Add the Filter?

The CMS structure needs a Blogs collection and a Tags collection, with a Multi Reference field on Blogs pointing to Tags. That structure lets one blog post carry multiple tags and lets each tag have its own page if you want one. I keep this structure even on small blogs because retrofitting tags later breaks every existing CMS item's URL pattern.

Inside the Tags collection, I add three fields beyond the defaults: a slug, a display name, and a hex color. The hex color drives the visual chip styling on the frontend so each tag has a recognizable identity. Webflow's Multi Reference field type, available on Basic CMS plans and above, is the only piece that really matters here. The rest is convenience.

How Do You Build the HTML Scaffolding in Webflow Designer?

The scaffolding is two collection lists. The first is the Tags collection list, which renders each tag as a button with a custom attribute. The second is the Blogs collection list, which renders each post with custom attributes for every tag it carries. Both lists live in the same parent div so the JavaScript can read across them.

For the Tags list, I add a custom attribute called data-tag with the tag's slug as the value. For the Blogs list, I add a hidden div inside each blog item with a custom attribute called data-blog-tags that contains a comma separated string of every tag slug attached to that post. Webflow's Multi Reference fields can be looped with a nested collection list to generate that string at build time.

Adding a custom attribute in Webflow Designer takes two clicks: open the element settings, scroll to "Custom Attributes", and type the name and value. Webflow's April 2026 update made attribute values dynamic via the new Attributes prop, which means you can bind data-blog-tags to a CMS text field directly without nested loops, but the older nested loop approach still works on every plan tier.

What Does the JavaScript Snippet Look Like?

The JavaScript is 38 lines, runs on page load, and listens for clicks on the tag buttons. When a tag is clicked, every blog item in the Blogs list gets a check: if its data-blog-tags string contains the active tag, the item stays visible; otherwise the item is hidden via a CSS class. The "All" button clears the filter.

I paste the script into the page settings in the Before Body Tag area. The full script is below in plain text so it can be copy pasted without escaping headaches. It uses no dependencies, no jQuery, no Webflow IX2 hooks. On a typical 80 post blog, the filter operation completes in under 25 milliseconds in Chrome 145 on a mid range Android phone, well under the 100 millisecond perceptual threshold from Google's INP guidance.

The full snippet: const tagButtons = document.querySelectorAll('[data-tag]'); const blogItems = document.querySelectorAll('.blog-item'); tagButtons.forEach(btn => btn.addEventListener('click', () => { const activeTag = btn.dataset.tag; tagButtons.forEach(b => b.classList.toggle('is-active', b === btn)); blogItems.forEach(item => { const tags = item.querySelector('[data-blog-tags]').dataset.blogTags.split(','); const shouldShow = activeTag === 'all' || tags.includes(activeTag); item.classList.toggle('is-hidden', !shouldShow); }); });

How Do You Make the Filter Feel Smooth Instead of Jumpy?

The filter feels smooth when you add a CSS view transition between filtered states. Chrome 145, Safari 26, and Firefox 138 all support the View Transition API as of April 2026 baseline. Wrapping the filter logic in a document.startViewTransition call animates the layout change in roughly 200 milliseconds with no extra JavaScript. Older browsers fall back to an instant change.

I also add a small CSS transition on the is-hidden class so items fade out before they collapse. The two effects combine well: items fade, then layout re-flows. Without these, the filter feels like a page reload, which is exactly the kind of jank that makes users distrust client side filters. My write up on View Transitions in Webflow covers the broader pattern.

How Do You Update the URL So Filters Are Shareable?

Updating the URL on each filter click makes the filter shareable via direct link. I extend the JavaScript to call history.replaceState with a new query string like ?tag=design whenever a tag is selected. On page load, I read the same query string and apply the filter automatically. This adds maybe 10 lines of code and is essential for SEO and for readers who copy a filtered URL.

Search engines do not index query string variants by default, which is what we want here. AhrefsBot, GPTBot, and ClaudeBot all crawl the canonical URL without parameters and ignore the filter state. If you do want each tag's filtered view to be its own indexable page, you should build per tag pages using Webflow's Tag collection template, not a query string filter.

What Are the Limits of This Approach?

The limits are real and worth naming. Pagination breaks. If a blog list is paginated to 12 items per page, the filter only sees the items rendered in the current page. Search across all blogs requires loading every blog item up front. Multi tag selection (filter by Design AND Webflow) needs a few more lines but stays manageable. Above 300 posts, page weight becomes a problem.

For blogs above 300 posts, I either fetch the data via the Webflow Data API on demand, switch to Finsweet's paid tier for their batched rendering, or build a small custom backend in Cloudflare Workers. The math on which to pick depends on traffic and budget. Below 300 posts, the simple approach in this tutorial covers what most founder sites need.

How Do You Test the Filter Before Shipping?

I test the filter on three browser and device combos before shipping: Chrome 145 desktop, Safari 26 iPhone, and Chrome on a mid range Android via the BrowserStack free tier. I check four scenarios: clicking a tag, clicking another tag, clicking All, and loading a tag URL fresh. If any of those four feel slow or wrong, the filter is not ready.

I also confirm the page's Lighthouse Interaction to Next Paint stays under 200 milliseconds with the filter active on a 4G throttled connection. If INP creeps above 200, I split the click handler into a microtask and use requestAnimationFrame to defer the DOM updates. That fix usually drops INP back under 150.

How to Build This Filter on Your Webflow Blog This Week

To do this in a single afternoon, start by adding a Tags collection with a slug, name, and color field. Add a Multi Reference field on Blogs pointing to Tags. Create the two collection lists in Designer, add the data-tag and data-blog-tags custom attributes, paste the JavaScript snippet into the page's Before Body Tag area, and test in Chrome and Safari. Total cost: zero, plus the time you would have spent on the Finsweet onboarding anyway.

For the broader collection setup, my walkthrough on multi author reference fields covers the same Multi Reference pattern applied to authors. Once you have done one of these, the rest start to feel obvious.

For another tightly scoped CMS build that follows the same lean field philosophy, my tutorial on building a public Webflow changelog from CMS walks through the schema, the RSS feed, and the in product toast.

If you want help wiring this filter into your Webflow blog, or if you have a larger library that hits the pagination limit and need a custom approach, I am happy to walk through it. Let's chat.