Discount rule sheet
Every promotion written as plain conditions and amounts, approved before code, so nothing is left to interpretation.
The Problem
When the Discounts Page Can't Say What Your Promotion Means
It shows up once a promotion depends on who is buying, what's in the cart, and where it ships. Shopify's own discounts cover single conditions, and stacked apps start fighting each other.
01 · Wrong buyers
First-order codes keep working for customers who've bought before.
The rule checks each customer's order count, so the code only fits new buyers.
02 · Wholesale tiers
Approved buyers can't get deeper discounts on the brands they stock.
Customer tags and cart totals set each tier, priced line by line.
03 · Shipping scope
A free shipping offer covers regions you didn't mean to include.
Shipping discounts check the delivery address and cart before they apply.
04 · App conflicts
Two discount apps change the same cart and fight over totals.
One app holds every rule, with combination settings you approve in advance.
Your wholesale buyers expect a deeper discount once their cart passes a set amount, but only on the brands they're approved for. A returning customer pastes a welcome code meant for first orders, and it works. Free shipping applies to the whole country when you meant one region. Two discount apps each rewrite the cart price, so the checkout total depends on which one loaded first. You fix orders by hand after every sale and quietly stop running the promotions that made money.
We start with what Shopify already does: segments, eligibility, and combination settings often cover more than stores expect. Where they stop, we write your rule as a discount function. One rule set then prices your cart lines, order, and shipping together. Your team edits thresholds in the admin, not in code. The discount becomes part of checkout instead of a script racing it.
Built-in options checked first
Segments, eligibility, and combinations get used before any code, because Shopify maintains them for free.
One function, three discount classes
The Discount Function API prices cart lines, the order subtotal, and shipping from one rule set.
Thresholds your team can edit
Amounts, tags, and dates sit in settings inside your admin, so promotions change without a developer.
Our Shopify Discount Functions Process
From Promotion Brief to Live Checkout Rules in Five Steps
You approve a written rule sheet before any code exists, then place test orders yourself on a development store before anything reaches your live checkout.
We read your current discounts, discount apps, and Shopify plan, plus the promotions you want to run next. You get a plain answer on what Shopify's own discounts cover and which rules need a function.
What's Included
What You Get With a Custom Shopify Functions App
Your rule sheet, the discount functions Shopify runs in checkout, admin settings, stacking rules, tested carts, and a guide for your team.
Compare Options
DeveloperLook vs a Discount App vs Built-In Discounts
Built-in discounts handle most single-condition offers, and App Store discount apps cover common patterns. Here's where each one breaks down once your rules depend on the customer, the cart, and shipping.
| Feature | DeveloperLookBest fit | Discount app | Built-in discounts |
|---|---|---|---|
| Setup time | 1 to 6 weeks | The same day | A few minutes |
| Upfront cost | From $650, fixed | Monthly app fee | Included in your plan |
| Rule logic | Any condition you approve | The app's preset patterns | Shopify's preset conditions |
| Customer targeting | Tags, order count, and spend | Varies by app | Segments and specific customers |
| Stacking control | Mapped per rule, then tested | Set inside the app | Per discount class |
| Testing | Test carts for every rule | Your own trial orders | Checkout preview by you |
| Code ownership | Custom app code is yours | Vendor keeps the code | |
| Plan needed | Plus for custom functions | Any Shopify plan | Any Shopify plan |
DeveloperLook
Discount app
- Setup time
- DeveloperLook: 1 to 6 weeksDiscount app: The same day
- Upfront cost
- DeveloperLook: From $650, fixedDiscount app: Monthly app fee
- Rule logic
- DeveloperLook: Any condition you approveDiscount app: The app's preset patterns
- Customer targeting
- DeveloperLook: Tags, order count, and spendDiscount app: Varies by app
- Stacking control
- DeveloperLook: Mapped per rule, then testedDiscount app: Set inside the app
- Testing
- DeveloperLook: Test carts for every ruleDiscount app: Your own trial orders
- Code ownership
- DeveloperLook: Custom app code is yoursDiscount app: Vendor keeps the code
- Plan needed
- DeveloperLook: Plus for custom functionsDiscount app: Any Shopify plan
Projects We've Built
Ecommerce Projects We Have Built
Online stores our team designed and built, with discount codes, checkout flows, and order dashboards. They show where we work, not builds of this exact service.
Havenly Furniture Ecommerce Website
- Furniture
- E-commerce
- Dashboard
Xinomin Fashion Ecommerce Website and Admin Dashboard
- Fashion
- E-commerce
- Dashboard
Sefinix Furniture Ecommerce Store and Dashboard
- Furniture
- Dashboard
- E-commerce
Fuison Fashion Ecommerce Website and Dashboard
- Fashion
- Dashboard
- E-commerce
What Our Clients Say
What Clients Say After Launch
Feedback from teams we have built online stores and checkout features for.
We had a pretty specific idea of what we wanted our website to become, but I wasn’t sure how easily we could explain all of it to a development team. There were quite a few moving parts, and we were working toward a deadline, so I expected a few things to get lost along the way. That never really happened. They understood what we were trying to achieve, kept us updated throughout the process, and got everything ready within the agreed timeline. The final site feels much easier to navigate, works beautifully on mobile, and is noticeably smoother for our customers. It was a huge relief seeing the original idea actually turn into the website we had in mind.
The mobile experience is probably my favourite part of the new site. We had spent a lot of time making sure the desktop version looked right, and the team kept pushing us to think about how everything would actually feel on a phone too. They were right. The navigation is clean, the interactions feel natural, and everything we’ve tested so far works exactly as it should. They also went through the links, forms, integrations, and other details more than once before launch, which I really appreciated. And even after going live, we could still reach out when something came up. The whole process felt friendly, organised, and surprisingly straightforward.
What I appreciate most is that the website is actually easy for us to manage now. We can update content ourselves instead of sending a developer a message every time we need to change something small. They also paid attention to the technical SEO side, which mattered to us because we didn’t want a new website to create problems for the traffic we already had. I’ve probably asked more questions than I should have since launch, but every question has been handled patiently and without any fuss. The team is easy to work with, they explain things clearly, and when we need something changed, they focus on getting it done rather than making the process complicated.
1,250+
Projects shipped
10+
Years of experience
Top 3%
Upwork Top Rated Plus
5 stars
Average review score
Want results like these?
Tell us what you are building. You get a reply within 24 hours on business days, then a written estimate.
Work Culture
Why Store Teams Trust Us With Their Discount Logic
A discount rule touches every order and every margin. These habits keep Shopify discount functions development predictable for your team and fair for your customers.
Admin discounts before code
Shopify segments can already target customers with no orders, and codes can be limited to specific customers. If the admin covers your promotion, we'll tell you before we quote.
Built on the current API
Shopify merged its product, order, and shipping discount APIs into one Discount Function API in 2025. Every function we write uses it, so you don't inherit a deprecated build.
Inside Shopify's run limits
Shopify caps each function at 11 million instructions for carts of up to 200 lines. We write production logic in Rust, as Shopify recommends, and test your largest carts.
Stacking decided up front
Customers can enter up to 5 product or order codes and 1 shipping code on one order. We decide which of your offers combine before launch, not after a margin surprise.
Tested on a development store
Every rule runs against test carts on a development store before it reaches your checkout. You place the same test orders and sign off.
Your app, your code
The function app installs on your store, and its code lives in your repository. Your team or another developer can change it later without us.
Overview
How do Shopify Functions work for custom discounts?
DeveloperLook builds custom discounts with Shopify Functions for stores whose promotions outgrow the admin. We write the rule sheet, build the function and its admin settings, set combination rules, and test every cart. Projects start at $650 and take 1 to 6 weeks, and the app and code stay yours.
DEVELOPERLOOK
Project facts · Shopify Discount Functions Development
- Service
- Shopify Discount Functions Development (rule sheet, function app, admin settings, testing)
- Typical timeline
- 1 to 2 weeks for setups, 3 to 6 weeks for custom functions
- Platforms
- Shopify Plus for custom functions; any plan for App Store apps
- Built with
- Discount Function API, Rust, GraphQL Admin API, Shopify CLI
- Experience
- 10+ years of development experience and 1,250+ shipped projects
- Post-launch support
- 30 to 90 days, depending on plan
- Communication
- Calls in US, UK, and AU business hours
- Starting price
- From $650 USD, fixed scope after a free discount review
Reviewed 7 Oct 2026 by Saimul Islam
Good fit
Shopify Plus stores selling wholesale
Your wholesale buyers need an extra discount by tag and order size, and a Shopify customer group discount from the admin can't price each brand differently.
Brands rewarding first and repeat orders
You want one welcome offer for first orders and a separate Shopify discount for specific customer tags, without codes leaking to the wrong buyers.
Stores with regional shipping offers
Your reduced shipping should depend on the delivery region and the cart's contents, which calls for Shopify custom shipping discount rules beyond flat thresholds.
Teams retiring stacked discount apps
You pay for two or three discount apps that change the same cart, and you want one app that holds every rule and its stacking settings.
Agencies with Shopify Plus clients
Your agency plans the promotion calendar, and you need the rules built, tested, and documented behind your brand.
Not a fit
Rebuilding retired Scripts
Your old Shopify Scripts also handled payment and delivery rules. Our Shopify Plus Checkout Customization page covers rebuilding those as functions together.
Bundle pricing only
Your offer is a fixed bundle or a mix-and-match box at one price. Our Shopify Product Bundles & Kits page fits that better.
Shipping rates, not discounts
You need carrier rates, zones, or local delivery fees rather than a shipping discount. Our Shopify Shipping Rates and Local Delivery Setup page covers that work.
Budget under $650
Your budget is under $650 and your offer is one code for one customer segment. Shopify's built-in discounts handle that without our help.
Not sure we're the right fit?
Book a free call or message us. We'll tell you honestly whether we're the right team.
Pricing
Transparent Starting Prices for Shopify Discount Functions
These are starting points in USD. Your final price depends on your Shopify plan, the number of rules, and how they combine, and you get a fixed proposal after a free discount review.
For stores on any plan whose offers fit Shopify's own discounts or one App Store app.
$650one-time, USD
- Free discount and app review
- Customer segments and eligibility set
- Up to 6 discounts configured
- Built-in discounts or 1 Functions-powered app
- Combination settings tested
- 30 days post-launch support
Recommended
For Shopify Plus stores that need up to 3 custom rules in their own app.
$1,950one-time, USD
- Everything in Discount Rules Setup
- Custom app on the Discount Function API
- Up to 3 rules across discount classes
- Settings screen in your admin
- Tag, order count, and spend targeting
- 60 days post-launch support
For Plus stores replacing several discount apps with up to 8 rules and market-specific offers.
$4,300one-time, USD
- Everything in Custom Function App
- Up to 8 rules in one app
- Market and currency specific rules
- Large-cart and run log testing
- Team guide and code walkthrough
- 90 days post-launch support
For Agencies
White-Label Discount Functions for Agencies and Studios
You own the client relationship. We supply the discount engineering behind your promotion strategy: rule sheets, Shopify Functions API work, admin settings, and test carts. Your client sees your team, and the app installs on their store.
How the partnership works
White label: your client only ever sees your brand
- Your client
- You, the agency
- DeveloperLook
Share the brief
Send the client's plan, current discounts, and the promotions on their calendar.
- Client needs
- You share the details
- Details received
We write and price
You get a rule sheet and a fixed quote to share with your client.
- Scope and plan
- Proposal to resell
- Your quoteYOUR LOGO
Build and hand off
We build, test with sample carts, and hand over a guide under your brand.
- Done by our team
- Your brand on it
- Handed to your clientDone
Partner with DeveloperLookDelivered under your brand
Stay client-facing
You lead the promotion planning while we build behind the scenes.
Fixed rule-set quotes
Each rule sheet priced up front, so your retainer math holds.
Documented rules
Every condition and setting written down for your account managers.
Flexible capacity
Senior Shopify developers for sale seasons without another hire.
The Right Technology for Your Project
Technology Stack
Shopify's own function runtime and APIs first, Rust for production logic, and a small admin app so your team edits rules without touching code.
Shopify
Rust
JavaScript- WebAssembly
GraphQL
React
Node.js- TypeScript
- Shopify CLI
- Development store
- Function replay
- Vitest
- Run logs
Cloudflare
Vercel
AWS
PostgreSQL
FAQ
Frequently Asked Questions
Straight answers on plan availability, customer-specific discounts, stacking codes, cost, and timelines.
Saimul IslamFounder & CEO, DeveloperLookStill have questions?
Send a message or book a call with the team.
Shopify discount functions development starts at $650 for admin discounts or one App Store app, set up and tested. A custom function app with up to 3 rules costs $1,950 on Shopify Plus. Up to 8 rules with market-specific offers costs $4,300, and every plan has a fixed price after the free review.
Most custom function builds take 3 to 6 weeks from rule sheet to launch. Setups that use Shopify's own discounts or an App Store app take 1 to 2 weeks. Most of that time goes into agreeing your rules and testing carts, since the code is usually the smaller part.
Partly: any plan can use App Store apps that contain functions, but custom apps with functions need Shopify Plus. That rule comes from Shopify's developer documentation. So stores on Basic, Grow, or Advanced get a Functions-powered public app configured, while Plus stores can own a custom app built around their rules.
You apply them through a discount function, which Shopify runs whenever the cart changes. The function reads the cart and customer, then returns discounts for lines, the order subtotal, or shipping. For simple order or shipping rules by customer tag or order count, custom discounts in Checkout Blocks on Shopify Plus can be enough.
Set the discount's eligibility to specific customers or to customer segments in Shopify admin. Shopify allows up to 5 segments on an automatic discount and up to 100 on a discount code. When the rule also needs tags, spend, and cart contents at once, a function handles that combination.
Tag your wholesale customers and give them a tag-based discount, or use Shopify B2B price lists, which work on Basic, Grow, Advanced, and Plus. A function adds what neither covers alone: an extra discount by brand, order size, or account tier on top of the wholesale price.
Yes, when the discounts are set to combine: Shopify allows up to 5 product or order codes and 1 shipping code per order. Each discount must allow the other's class in its combination settings. We map which of your offers stack, so two codes can't give away more than you planned.
They check the order count of the customer Shopify identifies at checkout, using a valid email address or phone number. Admin discounts use segments built on number of orders, and a function reads order count, tags, and amount spent directly. We test new, returning, and guest buyers before launch.
It lets an app add its own discount logic to your checkout without scripts in your theme. The Discount Function API, released in 2025, handles product, order, and shipping discounts in one function. We write production functions in Rust, which Shopify recommends, because JavaScript reaches instruction limits sooner on large carts.
Every plan includes 30 to 90 days of support for your live discounts. We watch the first orders, check the function's run logs, and adjust a rule if a cart prices wrong. The app installs on your store and the code lives in your repository, so every rule stays yours.
Saimul IslamFounder & CEO, DeveloperLookStill have questions?
Send a message or book a call with the team.
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