What's a reasonable QA budget or time allocation, as a percentage of total dev time, for checkout testing on a mid-market Shopify Plus store?
No published figure exists. Here is the honest answer
Checkout quality assurance (QA) is budgeted by test matrix, not as a percentage of development hours. No published benchmark sets a defensible checkout QA share: the public highlights of the World Quality Report 2025-26 carry none (Capgemini, October 2026). So count combinations to prove: payment methods × discount stacking × tax and duty × customer type × market × fulfillment.
- Published checkout QA benchmark
- NoneThe public highlights of Capgemini's World Quality Report 2025-26 carry no QA share of budget, and the full report is gated.Sources: Capgemini (World Quality Report 2025-26); OpenText (World Quality Report 2025: AI adoption surges in Quality Engineering, but enterprise-level scaling remains elusive)
- B2B carts
- No subscriptions, pre-orders or try before you buyShopify: B2B doesn't support purchase options, so prune those cells and keep one negative test that a B2B cart cannot take a selling plan.Source: Shopify developer docs (Apps and B2B)
- Subscription orders
- No order edits API, no draft ordersShopify: the order edits API doesn't support subscriptions, and subscriptions can't be used with draft orders, so add cells proving support can correct one without either tool.Source: Shopify Help Center (Considerations and payment gateways for subscription products)
- Shopify Scripts deactivated
- 30 June 2026Shopify deactivated every Script still published and names Shopify Functions as the replacement, so each rebuilt discount, shipping or payment rule needs its own test cells.Source: Shopify Help Center (Shopify Scripts and the Script Editor app)
Deploi’s call
Refuse the percentage. Ask for the test matrix and the cell count, and pay for that. A percentage of dev hours is a proxy for effort that has no causal link to checkout risk.
BuildFund a full checkout test matrix when
- Your discount, shipping or payment rules run as Shopify Functions, which Shopify names as the replacement for the Shopify Scripts it deactivated on 30 June 2026 (Shopify Help Center, October 2026).
- You sell business-to-business (B2B) or subscriptions, whose Shopify rules add and remove cells (shopify.dev, October 2026).
- You sell in more than one market or currency, so each payment and discount case runs once per market.
- Two or more apps place blocks in checkout. Deploi's conflict-debugging record scores an app register, a runbook and a synthetic checkout monitor BUILD once two apps touch the same surface (Deploi decision record, October 2026).
WaitKeep the matrix small when
- You sell in one market and one currency, with cards and Shop Pay only.
- You sell no subscriptions and no B2B.
- No two apps touch checkout, which is when Deploi's conflict-debugging record scores the monitor WAIT (Deploi decision record, October 2026).
Basis: Build or Buy Checkout Extension and Theme App Conflict Debugging?, our Build vs. Buy decision record, scored BUILD.
Why doesn't a percentage of development time work for checkout QA?
A percentage of development time doesn't work for checkout quality assurance (QA), because checkout risk comes from the number of states a customer can reach. That number has almost no relationship to how many hours went into building the storefront. A simple theme with five payment methods across four markets needs far more checkout QA than an elaborate theme selling one product domestically. So the QA line on a Shopify Plus migration quote's six line items should be priced from a count of test cases, not from the development total.
Is there a published benchmark for checkout QA as a share of budget?
No published benchmark sets checkout quality assurance (QA) as a share of development time or budget. Capgemini's World Quality Report, now in its 17th edition, is the long-running industry survey of software testing. Its 2025-26 public highlights cover generative AI adoption, automation barriers, synthetic data, skills and production data, with no QA share of budget (Capgemini, October 2026). The full report sits behind a registration form, and OpenText's November 2025 announcement of it carries no budget figure either (OpenText, October 2026). Earlier editions, through 2017, put testing at 18% to 35% of total information technology (IT) budget (Capgemini's 15-year review, October 2026). That share is neither checkout-specific nor a share of development time. In Deploi's search, figures that put QA at 20 to 25% of development do not trace to a checkout-specific source either. So Deploi will not quote a number it cannot stand behind.
What does a checkout test matrix count?
A checkout quality assurance (QA) test matrix counts every combination of six axes that a mid-market Shopify Plus store must prove works. Build the matrix, count the cells and cost each one, so every line of the QA budget traces to a test.
| Axis | Values to enumerate |
|---|---|
| Payment method | Shopify Payments cards, Shop Pay, PayPal, Apple Pay and Google Pay, gift card, manual or offline |
| Discount state | None, automatic, code, automatic and code stacked, free shipping, at the threshold |
| Tax and duty | Domestic tax, tax-exempt customer, duties-inclusive international |
| Customer type | Guest, logged in, business-to-business (B2B) company contact, subscriber |
| Market and currency | One value per active market |
| Fulfillment | Standard shipping, local pickup, split shipment, pre-order |
Multiply the axes, then prune the combinations that cannot co-occur. What is left is a countable number of scenarios, each a real test with a real cost. That number is defensible in a budget conversation in a way a percentage never is.
Which Shopify rules add or remove cells in the matrix?
Four Shopify rules add or remove cells in a checkout quality assurance (QA) matrix: Scripts rebuilt as Functions, business-to-business (B2B) purchase options, subscription order limits and Managed Markets exclusions.
- Scripts rebuilt as Functions. Shopify deactivated every Shopify Script still published on 30 June 2026 and names Shopify Functions as the replacement (Shopify Help Center, October 2026). Each discount, shipping or payment rule rebuilt as a Function adds its own test cells. Which checkout deadlines hit which plans is its own answer.
- B2B purchase options. "B2B doesn't support purchase options, such as subscriptions, pre-orders, and try before you buy" (shopify.dev, October 2026). Prune those cells, then keep one negative test: a selling plan on a B2B cart returns "Only one-time purchase is available for B2B orders" (Shopify Community, thread opened January 2025).
- Subscription order limits. Shopify's order edits application programming interface (API) doesn't support subscriptions, and subscriptions can't be used with draft orders (Shopify Help Center, October 2026). So add cells proving support can correct a subscription order without either tool.
- Managed Markets exclusions. Shopify Managed Markets supports neither B2B orders nor subscriptions (Shopify Help Center, October 2026), so those cells come out of every international market. Its duties-inclusive prices change what the buyer sees, so test the display, not just the calculation; how Managed Markets fees reach international prices is its own answer.
What should a checkout QA phase deliver?
A checkout quality assurance (QA) phase should deliver coverage and evidence: a matrix with a dated pass state per cell, re-runnable before each release. If your agency's QA line produces a Slack message saying "checkout tested", you bought a feeling. Part of the matrix can keep running after launch. Deploi's conflict-debugging record keeps each reproduced checkout failure as a synthetic checkout test that runs every 15 minutes in each region you sell (Deploi decision record, October 2026). So an app update that breaks checkout raises an alert before shoppers notice.
When should you spend less on checkout QA?
Spend less on checkout quality assurance (QA) when the matrix is small, because the count of test cells sets the budget.
Deploi’s point of view
Our own position, from building on Shopify. Kept apart from the sourced facts above.
- What we’ve seen
- Discount stacking and tax-exempt customers are where defects concentrate, and both are combinations rather than features, which is exactly why they survive feature-by-feature testing and reach production.
- Where we disagree
- Agencies quote QA as a share of development because buyers ask for it that way. We think that norm is the reason checkout defects ship: it budgets testing against how much was built rather than against how many states a customer can reach.
- What this page adds
- that the parent's QA line item should not be quoted as a percentage at all, the six axes that define a Plus checkout matrix, and the Shopify rules that add or remove cells in it: Scripts rebuilt as Functions, B2B purchase options, subscription order limits and Managed Markets exclusions.
Decision records behind this answer
When this answer changes
- Capgemini, or another survey, publishes a checkout QA share of budget.
- Shopify lets B2B orders carry subscriptions, pre-orders or try before you buy.
- Shopify lets Managed Markets carry B2B orders or subscriptions.
- The order edits API starts supporting subscriptions, or subscriptions start working with draft orders.
- Shopify ships a native synthetic checkout monitor, or Deploi re-scores its conflict-debugging record.
Related questions
This follows from What line items typically make up a full Shopify Plus migration quote (discovery, design, dev, QA, training, post-launch support)?
- Does the checkout.liquid shutdown affect stores on every Shopify plan, or only Shopify Plus stores?
The checkout.liquid shutdown hit Shopify Plus stores only, because checkout.liquid, the theme file for custom checkout code, was a Plus-only layout (shopify.dev, October 2026).
- How much does adding international/multi-market complexity (Managed Markets setup, multi-currency) typically add to a Shopify Plus project quote?
Shopify Managed Markets, the cross-border service with Global-e as merchant of record, adds a per-transaction fee to Shopify Plus projects, not a build line.
- How much should we budget specifically for subscription-migration risk mitigation (QA, parallel-run, customer support surge) as its own line item separate from the core platform migration budget?
Subscription-migration risk mitigation deserves its own budget line, sized from five jobs rather than a percentage, because Deploi found no published benchmark that sets one.
Sources
Every figure on this page traces to one of these. Official and vendor pages are checked on the date shown; Deploi records are our own published decisions.
- Capgemini, World Quality Report 2025-26
- OpenText, World Quality Report 2025: AI adoption surges in Quality Engineering, but enterprise-level scaling remains elusive
- Shopify developer docs, Apps and B2B
- Shopify Help Center, Considerations and payment gateways for subscription products
- Shopify Help Center, Shopify Scripts and the Script Editor app
- Shopify Help Center, Requirements and considerations for using Managed Markets
- Shopify Community, Wrong selling plan, error: Only one-time purchase is available for B2B orders
- Capgemini, 15 years of World Quality Report: A journey in quality engineering and testing
- Deploi Build vs. Buy, Build or Buy Checkout Extension and Theme App Conflict Debugging?