Controller

The Controller is your store’s rulebook for what codes and gift cards are allowed to do at checkout. It applies to everything — codes you created in PromoLock, codes made in the Shopify admin, and codes generated by other apps. If a code is typed into your checkout, the Controller has a say.

It has three layers, top to bottom on the page: Quick controls for the common cases, Rule variables (the tags and collections your rules can reference), and Custom rules for everything else.

Nothing takes effect while you’re editing — a save bar appears as soon as you change something, and your changes go live the moment you hit Save.

Quick controls

Quick controls are one-switch locks. Each one is a card with a switch — turn it on, adjust its options, save. They’re split into two tabs: Discount Code and Gift Card.

Discount Code tab

Discount Lock

Blocks discount codes at checkout. The Mode select decides how strict:

Mode	What it does	Use it when
Block all codes	No discount code works at all.	Sale events where codes shouldn’t apply, or an emergency shut-off.
Block all codes except	Only the codes you list under Allowed codes still work.	You run a tight ship — a few official codes, nothing else.
Block only these codes	Everything works except the codes you list under Blocked codes.	A code leaked to a coupon site and needs to die today.

The code lists accept patterns, so “block everything that starts with SUMMER” is one entry, not fifty.

Discount Stacking Lock

Stops customers from combining multiple discount codes on one order. When two or more codes land in a checkout, the first one is kept and the extras are rejected with your message.

Stacking exceptions is a list of codes that live outside the limit: an exception code always applies, and it doesn’t count toward the limit — so a customer can use your free-shipping code alongside a regular discount if that’s the combination you actually want.

Lock Discount Usage On Sale Items

Stops discount codes from being used on carts that contain marked-down products — the classic double-dip. A product counts as “on sale” when its current price is below its compare-at price.

The Trigger select has two modes:

Trigger	What it does
Block if cart has any sale item	One sale item anywhere in the cart blocks all codes. The strictest option.
Block when sale items exceed % of cart total	Codes are blocked only once sale items make up more than your Threshold (%) of the cart’s value.

The threshold is measured in money, not item count: with a threshold of 50, a customer whose cart is $60 regular-priced and $40 sale items can still use a code (40% of cart value is on sale); tip the balance past half and codes stop working. This mode lets bundled carts through while still blocking pure sale-hauls.

Gift Card tab

Lock	What it does
Gift Card Lock	Blocks gift cards as a payment method entirely.
Gift Card Stacking Lock (Shopify Plus)	Only one gift card can be applied per order.
Gift Card & Discount Stacking Lock	A discount code and a gift card can’t be used on the same order — closes the “discounted purchase paid with a discounted-purchase gift card” loop.

Code patterns

Every code list in PromoLock — allowed, blocked, exceptions, rule triggers — accepts patterns, not just exact codes. The # symbol is the wildcard:

You type	It matches
`WELCOME10`	Exactly `WELCOME10`, nothing else.
`VIP#`	Any code starting with VIP — `VIP2026` ✓, `VIPGOLD` ✓, `MYVIP` ✗
`#2026`	Any code ending with 2026 — `SALE2026` ✓, `2026SALE` ✗
`#SAVE#`	Any code containing SAVE — `BIGSAVE50` ✓, `WEEKLYSAVE` ✓

Matching ignores upper/lowercase. Inside any code field, the expand button opens a bigger editor that labels each entry (“Starts with:”, “Contains:”) so you can see how it will be read.

Error messages

Every lock and every block rule can carry its own error message (up to 75 characters) — this is what the customer sees on the discount field when their code is rejected. Leave it blank and a sensible default is used, like “This code is not valid at this time.”

If your store sells in multiple languages, the translate button next to the field opens a Localization editor — one message per language, with your default language used as the fallback.

Rule variables

Before custom rules can reference your tags or collections, you register them here — three tiles: Customer tags, Product tags, and Collections, each holding up to 10 values. Rules then pick from these lists rather than free-typing, which keeps typos from silently breaking a rule.

If a condition like “Customer tag” shows no options, this is why — add the tag as a variable first.

Custom rules

When a quick lock is too blunt, write a rule. Rules live in a list — each with an on/off switch, a Block/Allow badge, and a one-line summary — and you can keep a rule in the list but disabled while you think it over.

A rule has four parts, in the order the editor shows them:

Name. Optional, for your own sanity in the list.

Action. Block (with your custom error message) or Allow. Allow rules are exceptions — they punch holes through your other rules (see which rule wins).

Trigger — which codes the rule watches.

All codes — optionally minus an Except list.
Specific codes — only the codes/patterns you list.

Conditions — when the rule applies. Add as many as you need; all of them must be true for the rule to fire. A rule with no conditions always applies to its triggered codes.

Condition	Checks	Operators
Cart subtotal	The cart’s subtotal	Greater than / Less than / Equals
Product in cart	Specific products (picked from your catalog)	Has any of / Has all of / Has none of
Product from collection	Products from a Collections variable	Has any of / Has all of / Has none of
Product with tag	Products carrying a Product tags variable	Has any of / Has all of / Has none of
Cart has sale item	Whether any cart item is marked down	Is true / Is false
Customer is logged in	Guest vs. signed-in checkout	Is true / Is false
Customer is new	The signed-in customer has zero past orders	Is true / Is false
Customer tag	Tags on the customer (from a Customer tags variable)	Has any of / Has all of / Has none of
Discount code count	How many codes are on the order, with an optional “don’t count these” list	Greater than / Equals / Less than

Which rule wins

Three things to remember about ordering:

Rules run top to bottom, and a later rule wins. If rule 1 blocks VIP# and rule 3 allows VIPGOLD, VIPGOLD gets through. Put your exceptions below the broad rules they carve out of.
Quick controls always have the last word. They run after all custom rules — an Allow rule can’t override Discount Lock, the stacking lock, or the sale-items lock. Exceptions to a quick control go in that control’s own exception/allowed list.
A disabled rule does nothing — it’s saved, but skipped.