Can I edit robots.txt on Shopify?

Yes. Shopify generates a default robots.txt, and you can customise it by adding a robots.txt.liquid template in the theme code editor. Shopify's own documentation recommends keeping the default rules and adding to them, because removing them can expose checkout, cart and search URLs to crawlers.

Should collection-based product URLs be canonicalised to /products/?

In most cases yes, and Shopify's default output already does it. It's also worth checking that theme links point directly at /products/ URLs, since that reduces how often Google encounters the collection-based variants in the first place.

Does switching themes affect SEO on Shopify?

It can. Titles, meta descriptions and product data stay in the admin, but the theme decides how they're rendered, including heading levels, canonical output and any hreflang or structured data. Compare those on a few key templates before and after publishing a new theme.

Does Deltio need a Shopify app or admin access?

No. It reads the public storefront, the sitemap and robots.txt, so it works on any Shopify store without installing anything, and uninstalling apps on the store doesn't affect it.

How much does Deltio cost?

Starter covers up to 50 sites and 5,000 URLs for £24 / €29 / $31 a month, or £20 / €24 / $26 a month billed annually. Professional (up to 200 sites) is £49 / €59 / $64 a month and Enterprise (up to 500 sites) £119 / €139 / $149 a month. Every plan includes a 14-day free trial.

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How to Monitor a Shopify Site for SEO Changes

To monitor a Shopify site for SEO changes, watch the things themes and apps can alter without anyone editing content: canonical tags on products and collections, noindex on search and filter URLs, title and meta templates, robots.txt and app-injected marketing tags. Shopify generates much of this markup automatically, which also means a theme update or a new app can change it automatically, with no ticket and no warning.

That's the trade-off with the platform. It handles a lot of technical SEO for you, but because canonicals, pagination and robots rules come from Shopify and the theme rather than from someone's hand, they shift whenever the platform, the theme or an app does. For an agency with several stores, the typical failure is an app installed for one purpose that changes markup relevant to something else.

Where Shopify SEO changes come from

Product URLs that exist more than once

A Shopify product is reachable at /products/blue-shirt, and, depending on how the theme builds links, also at /collections/shirts/products/blue-shirt. Variant selection adds ?variant= URLs on top. The platform's default output puts a canonical pointing at the /products/ URL on these pages, which is what keeps them from competing with each other. If a theme customisation or an app changes that tag, you have a duplication problem even though no page was added. Our guide on how to check for duplicate content explains how to spot it.

Themes

The theme's Liquid files, mainly theme.liquid and the section and snippet files it pulls in, decide how <title>, meta description, H1 and hreflang are output. Publishing a new theme, or updating the current one to a new version, can change that output across every product and collection in one go. A heading that was an H1 in the old theme may be an H2 in the new one.

Apps

Review widgets, upsells, translation apps, pop-ups and page builders inject code into the storefront. Some add their own structured data or hreflang, some add tracking scripts, and removing an app doesn't always remove everything it added to theme files.

robots.txt.liquid

Shopify serves a default robots.txt, which you can override by adding a robots.txt.liquid template to the theme. That's useful for blocking extra parameter URLs, but it also means a mistaken rule ships with a theme change like any other edit, and a theme swap can bring back the default or drop a customisation.

Search, filter and tag URLs

Internal search at /search and filtered collection URLs produce many thin pages. Shopify's default robots.txt disallows a number of these patterns, but whether filtered pages also carry noindex, and how they link, depends on the theme.

A practical watch list

Checking by hand after every app install or theme update isn't realistic on a store with hundreds of products. What works is a small, fixed set of checks run against a baseline. For each store:

canonical on product and collection pages
noindex on pages that should be indexed, and its absence where it should be present
title and meta description on key templates
H1 on product and collection pages
robots.txt content
URLs in sitemap.xml, which on Shopify is an index pointing to child sitemaps for products, collections, pages and blogs
GA4, GTM and Meta Pixel on the storefront

Marketing tags deserve a specific mention on Shopify, because they are often added through apps or the Customer events settings rather than hard-coded, so they appear and disappear with app changes. More in marketing tag monitoring.

Using Deltio on Shopify stores

Deltio checks the live storefront from outside, so there is no Shopify app to install and no staff account to create, and changes to the store's apps can't switch the monitoring off. On a daily cycle it reads the sitemap and the pages in it, checks noindex, canonical, title, meta description and H1, and compares the result with the previous check. robots.txt changes, sitemap URLs added or removed, and GA4, GTM or Meta Pixel going missing are reported too, as are cookie consent banners. Alerts go to Slack or email for that store, naming the affected URLs.

A few limits apply. Checks run daily, so a change made at 10am is reported on the next cycle, not in real time. Deltio doesn't measure page speed or Core Web Vitals. It also doesn't know why a change happened: it can tell you the canonical changed on 40 product pages, but working out which app or theme edit did it is still your job. On Starter the limit is 5,000 URLs across your sites, which matters for large catalogues.

If you look after several stores, start with the ones running the most apps or with the busiest merchandising team, since they change most. You can add a store on a 14-day trial.

Frequently asked questions

Can I edit robots.txt on Shopify?: Yes. Shopify generates a default robots.txt, and you can customise it by adding a robots.txt.liquid template in the theme code editor. Shopify's own documentation recommends keeping the default rules and adding to them, because removing them can expose checkout, cart and search URLs to crawlers.
Should collection-based product URLs be canonicalised to /products/?: In most cases yes, and Shopify's default output already does it. It's also worth checking that theme links point directly at /products/ URLs, since that reduces how often Google encounters the collection-based variants in the first place.
Does switching themes affect SEO on Shopify?: It can. Titles, meta descriptions and product data stay in the admin, but the theme decides how they're rendered, including heading levels, canonical output and any hreflang or structured data. Compare those on a few key templates before and after publishing a new theme.
Does Deltio need a Shopify app or admin access?: No. It reads the public storefront, the sitemap and robots.txt, so it works on any Shopify store without installing anything, and uninstalling apps on the store doesn't affect it.
How much does Deltio cost?: Starter covers up to 50 sites and 5,000 URLs for £24 / €29 / $31 a month, or £20 / €24 / $26 a month billed annually. Professional (up to 200 sites) is £49 / €59 / $64 a month and Enterprise (up to 500 sites) £119 / €139 / $149 a month. Every plan includes a 14-day free trial.