Guide
How to spy on a Shopify competitor's store
8 min read
'Spying' on a competitor sounds shady, but most of it is just reading what a Shopify store already publishes publicly - its catalog, prices, best sellers and new launches. You don't need shady tools or logins. This guide walks through every free, legitimate way to study a Shopify competitor, and how to stop doing it by hand.
1. See their entire catalog
Start with everything they sell - not just what's in the menu. Every public Shopify store exposes its full catalog at /products.json, including products that aren't linked anywhere:
https://competitor.com/products.json?limit=250
2. Study their prices and sales
Each variant in products.json carries price and compare_at_price, so you can read their exact prices and tell what's on sale and by how much. Tracking this over time shows their pricing strategy: when they discount, how deep, and how often.
3. Find their best sellers
Shopify's best-selling sort reveals what's working for them, straight from the URL:
https://competitor.com/collections/all?sort_by=best-selling
4. Catch their new launches
New products are how competitors test demand. Sort their catalog by newest to see latest drops, or watch for products appearing in products.json that weren't there before:
https://competitor.com/collections/all?sort_by=created-descending
5. Watch their stock movements
The available flag on each variant tells you what's in or out of stock. A product that keeps selling out is usually a winner; a restock is a signal to pay attention. Tracking sell-outs and restocks over time is one of the most useful competitive signals there is.
6. See what apps and tech they use
View the page source (right-click > View Page Source) and scan for script tags - you'll often spot the review app, upsell app, email tool and theme they run. Tools like BuiltWith or Wappalyzer do this automatically. It tells you how they merchandise and where they invest.
7. Study their ads and marketing
The Meta Ad Library (facebook.com/ads/library) shows every ad a brand is currently running on Facebook and Instagram - free. Search their brand name to see their creatives, offers and angles. Combine that with their promo banners and free-shipping thresholds for the full marketing picture.
8. Tools that speed this up
You can do everything above by hand, but a few free or freemium tools make it faster:
- Koala Inspector (Chrome extension) - one-click view of a store's likely best sellers, its theme, and the apps it runs.
- BuiltWith / Wappalyzer - auto-detect the platform, theme and tech stack of any site.
- Meta Ad Library - every Facebook and Instagram ad a brand is currently running, searchable by name, free.
- SimilarWeb - ballpark traffic volume, top channels and audience geography for a store's domain.
- Semrush / Ahrefs - the keywords and pages a competitor ranks for, and who links to them (freemium).
Is this legal and ethical?
Reading data a store publishes publicly to its own storefront is generally fine - it's the same information any shopper can see. You're not bypassing logins or accessing private systems. Just be respectful: don't hammer their servers, and don't copy their copyrighted content wholesale.
Stop spying manually - automate it
The problem with all of this is time. Doing it properly means checking every competitor's catalog, prices, stock and new products regularly - and you'll miss things the week you get busy. The valuable part is the change, and changes happen when you're not looking.
Shop Sentry does the watching for you. Paste a competitor's Shopify domain and it monitors their whole store - price drops, restocks, sell-outs, new launches and removals - then alerts you by email or Telegram the moment something happens. It's competitor spying on autopilot, free on your first store.
Frequently asked questions
Is spying on a Shopify competitor legal?
Reading public storefront data a store publishes itself is generally fine - it's what any customer can see, and you're not bypassing any login. Don't overload their servers or republish their copyrighted content. See our dedicated legality guide for the detail.
Can I do it for free?
Yes. The catalog (products.json), prices, best-selling sort, new-arrivals sort, stock flags, the ad library and tech-stack lookups are all free. Automating the monitoring is where a tool saves you time.
What can't I see?
Exact inventory counts, sales/revenue numbers, customer data, and anything behind login or in the Admin API. Public data gives you catalog, prices, availability and timing - not private figures.
How do I keep up without checking manually every day?
Use a monitor like Shop Sentry: add the competitor's domain once and get alerted automatically whenever their prices, stock or products change.