Mastiff

Stop orders that break your rules

Minimum order amounts, quantity limits, case packs and one-per-customer, enforced inside Shopify checkout. Shop Pay and Apple Pay included. No theme code.

Install free on ShopifySee how it works

1 rule free forever. No card needed. Paid plans from $4.99/mo, 7-day trial.

Shopify checkout showing an order blocked because it is below the minimum order amountWhat the shopper sees at checkout
Every checkout pathCart page, direct links, Shop Pay, Apple Pay, Google Pay. Nothing to skip.
Test before you publishPaste any cart into the simulator. What it says is what checkout enforces.
Works on every planBasic to Plus. Uses Shopify's own checkout validation, not a theme hack.

Which rule do you need?

One app, four rule types. Mix them.

Minimum order"Orders must be at least $50." By value or by item count. Store-wide or per collection.
Maximum quantity"No more than 2 per order." Stop bots and resellers on drops. Per product, per variant, per cart.
Sell in multiples"Only in packs of 6." Case packs and wholesale units, enforced at checkout, not on the product page.
One per customer"One per customer, ever." Counts across past orders, not just the current cart.

Install free on Shopify

How it works

Three steps, about two minutes.

The Mastiff Order Limits rule builder with a minimum order amount being set

1Write the rule

Pick the products or collections, set the number. The app reads the rule back in plain English so you can check it.

The simulator showing a test cart result against the active rules

2Test it

Paste a cart into the simulator. Green passes, red shows exactly what the shopper would read.

Shopify checkout blocking an order and showing the merchant's own message

3Turn it on

Checkout blocks the order and shows your message. Every path, every wallet, every plan.

Pricing

Start free. Upgrade when you need more rules.

Free

$0

One rule, forever. Enough for a single minimum order amount.

  • 1 active rule
  • Full simulator
  • All checkout paths
Install free
Most stores

Essential

$4.99/mo

Most stores. A minimum plus a max-quantity rule or two.

  • Up to 5 active rules
  • Everything in Free
  • 7-day free trial
Start free trial

Unlimited

$14.99/mo

Wholesale and multi-collection stores with many rules.

  • Unlimited rules
  • Everything in Essential
  • 7-day free trial
Start free trial

Founders rate: first 100 stores on any Mastiff app

The top plan for a net $8.49 a month via an automatic credit, for as long as you stay subscribed. We would like to hear from you: email [email protected] with your .myshopify.com domain. The credit is applied to paid plans either way.

Install free

Straight answers

Does it work with Shop Pay and Apple Pay?

Yes. Rules run inside checkout validation, which every express wallet passes through. Theme-based apps miss these.

Do I need Shopify Plus?

No. Works on Basic, Shopify, Advanced and Plus.

What about POS and draft orders?

Those do not go through online checkout, so no online rule applies to them. Ours included.

Will it slow down checkout?

No. The check runs server-side in Shopify's own validation step, in milliseconds.

Can shoppers still add a small cart?

Yes. The rule is checked at checkout, so they can keep adding items. They just cannot complete the order below the minimum.

What if I get stuck?

Email [email protected]. We will get back to you within the same day.

Set your first rule in two minutes

Free forever for one rule. No card.

Install free on Shopify