Every Shopify store publishes a JSON feed of its catalog at /products.json. It needs no API key, no app, and no authentication — it's the same data the storefront theme reads. This is the single most useful endpoint for anyone doing price monitoring, catalog analysis, or competitor research on Shopify, and it's badly under-documented. Here's everything it actually returns and how to use it.

The URL

https://any-store.com/products.json

By default it returns the first 30 products. Two query params matter:

• ?limit=250 — the maximum page size (250 is the hard cap; asking for more still gives 250).
• ?page=2 — paginate. Keep incrementing until you get an empty products array.

So the full catalog of a large store is just a loop:

import json, ssl, time, urllib.request, urllib.error

def fetch(url):
    req = urllib.request.Request(url, headers={"User-Agent": "Mozilla/5.0"})
    for ctx in (ssl.create_default_context(), ssl._create_unverified_context()):
        try:
            return urllib.request.urlopen(req, timeout=25, context=ctx).read()
        except urllib.error.URLError:
            continue
    raise RuntimeError("fetch failed: " + url)   # fail loudly, don't return None

def all_products(base):
    page, out = 1, []
    while True:
        data = json.loads(fetch(f"{base}/products.json?limit=250&page={page}"))
        batch = data.get("products", [])
        if not batch:
            break
        out += batch
        page += 1
        time.sleep(0.5)                            # be polite between pages
    return out

products = all_products("https://onyxcoffeelab.com")
print(len(products), "products")

What each product contains

A product object has these fields:

The variant fields (where the money is)

Prices live on variants, not the product. Each variant gives you:

Three things you can build in an afternoon

1. Price monitor — save {sku: price} each run, diff against last run, alert on changes.
2. Sale detector — flag any variant where compare_at_price > price. You now know exactly what a competitor is discounting and by how much.
3. Stock watch — track available flipping to false; a competitor selling out is your window to hold or raise price.

Honest limits

• Published products only. Drafts and unpublished items don't appear.
• available is a boolean, not a count. You can't see *how many* are left, just in/out of stock.
• Prices, not cart discounts. Automatic cart-level or code-based discounts won't show — but compare_at_price covers standard sale pricing.
• Not every store is Shopify. Check by opening the URL; if you get JSON, it's Shopify. Other platforms (VTEX, BigCommerce) have their own public endpoints.
• Be polite. This is public data, but hammering it is pointless — once a day catches real pricing moves.

Turn it into something you'll actually use

The open-source tool that does the save-and-diff (price + sale + stock) for you is here: github.com/willylam2222-bot/priceprobe. If you'd rather just get the answer, send me a few competitor URLs and I'll return a clean report of their prices, sales, and stock: willyverse188.gumroad.com/l/kphhe.

The endpoint is public and free. Now you know exactly what's in it.