SHOPIFY · MODULE 08 OF 08 | breadcrumb: Home > Learn > Shopify > Modules > 08 Apps, Flow and Functions
Module 08: Shopify Flow vs Functions vs apps
Shopify Flow, Functions and apps each cover a different side of the store: Flow handles work after an event, Functions change how checkout behaves and apps cover the rest. This lesson shows which job goes where.
Quick answer
Use Shopify Flow for back-office automation (tags, alerts, holds, labels); it is free on every plan from Basic up. Use Shopify Functions, usually through an app, for checkout logic such as discounts, shipping and payment rules, since Scripts stopped on Jun 30, 2026. Use apps for jobs Shopify does not cover, and audit them quarterly.
Lesson 8 of 8 in our free Shopify guide. Read it in about 10 minutes, then work through the checklist at the end.
Which job goes to Shopify Flow, Functions or an app?
Flow for work after an event, Functions for how checkout behaves and apps for jobs Shopify does not cover.
| Job | Tool | Why |
|---|---|---|
| Tag, route, hold or alert on orders and stock | Shopify Flow | Free on Basic and above; triggers, conditions and actions in the admin |
| Discounts, shipping rates, payment methods at checkout | Shopify Functions (through an App Store app on any plan, or a custom app on Plus) | Replaced Shopify Scripts, which stopped running on Jun 30, 2026 |
| Code or widgets on the storefront | App embed blocks | Storefront script tags stop loading on Mar 1, 2027 |
| Analytics and conversion tracking | Web pixels and channel apps | Replace Thank you page Additional scripts and analytics-only script tags (shopify.dev changelog, Aug 24, 2026) |
| Email, reviews, helpdesk, subscriptions, shipping | Built-in tool first, then a specialist app | See Tools and apps |
One job, three tools: a worked example
Say you want free shipping for customers who have bought three or more times (illustrative example). No single tool does it all, and that is normal.
- 01Flow tags the customer.
Trigger: order created. Condition: the customer now has three or more orders. Action: add a customer tag such as "loyal".
- 02A Function changes checkout.
A shipping app built on Shopify Functions, or a custom Function, offers the free rate only to customers with that tag.
- 03An app or Shopify Messaging tells the customer.
A short email explains the new perk, so it brings them back rather than surprising them at checkout.
Flow cannot change what checkout shows, and a Function does not run after the order. Knowing which side of checkout a job sits on tells you which tool it needs. Write each piece down with its owner, because a rule split across three tools is easy to break when someone edits one of them.
Replacing Scripts with Functions
In the admin go to Apps, Script Editor, Replace Shopify Scripts. The customizations report lists what was active in Payment gateways, Shipping and Product discounts, with recommended apps and Functions tutorials. It exports as a CSV. Recreate the rules you still need with an app built on Functions or a custom app built in the Dev Dashboard; custom apps created in the Shopify admin do not support App Bridge (Shopify Help Center, read Oct 20, 2026). Test each rule with real orders.
The quarterly app audit
List every app with its job, monthly cost at current volume, owner and whether Shopify now covers the job (Flow, Inbox, Messaging, Subscriptions, Search and Discovery). Ask each developer whether the app still uses storefront script tags. Cancel what nobody uses. Sidekick can help review settings and draft changes, and it presents changes for your review before applying them.
Example audit (illustrative · sample figures): a store lists 14 apps costing $612 a month. Three duplicate a built-in tool: a chat widget (Shopify Inbox does the job), a basic email tool (Shopify Messaging) and a stock alert app (a Flow workflow). Two more have not been opened in 90 days. One older app still uses storefront script tags and its developer has no plan to move. Canceling the five unused or duplicate apps and replacing the sixth saves money, removes page weight and leaves fewer systems that can disagree. Record the decisions with a date, so the next audit starts from them.
Key takeaways
- Flow for back-office automation; Functions for checkout logic; apps for everything else.
- Every Script rule you still need must now live in a Function or an app.
- Audit apps every quarter; plan for the Mar 1, 2027 script tag cut-off.
Do this now
- Run the Scripts customizations report if you were on Plus.
- Build the first five Flow workflows on the Automation page.
- List apps and ask about script tags.
- Cancel one app that duplicates a built-in tool.
Tool for this lesson: Shopify Flow; Sidekick; the Scripts customizations report; Functions-based discount and shipping apps from the Shopify App Store.
Problems and fixes at this stage
| Problem (buyer's words) | Cause | Fix | Relay Module or service | How to measure |
|---|---|---|---|---|
| "Our discount rules stopped working." | Scripts ended | Rebuild on Functions | A Relay Module (from $750) | Real-order tests passed |
| "We pay for apps we don't need." | No audit | Quarterly audit, move jobs to Flow | Ops Desk monthly app audit | Monthly app spend |
Talk it through with an ops lead
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What is the difference between Shopify Flow and Shopify Functions?
Flow automates back-office tasks after events happen, such as tagging an order or sending an alert. Functions change how checkout behaves, such as which discounts, shipping rates or payment methods apply. Many stores use both together: Flow sets a tag, and a Function reads it at checkout.
Do I need a developer for Shopify Functions?
Not always. Many apps in the Shopify App Store are built on Functions and need no code, and "stores on any plan can use public apps" that contain them. Custom logic needs a developer and a custom app built in the Dev Dashboard, and only Plus stores can use custom apps that contain Function APIs (shopify.dev, read Oct 20, 2026). Ask any developer for a written description of each rule and a test plan, so you can check it after every change.
Are Shopify Scripts coming back?
No. Shopify says Scripts were deprecated as of Jun 30, 2026 and published Scripts were deactivated (Shopify Help Center). If a discount, shipping or payment rule changed around that date, it probably lived in a Script and now needs a Function or an app. The full timeline is on What's new in 2026.
What are storefront script tags and why do they matter?
An older way for apps to add code to your store. No new ones from Oct 1, 2026; Shopify stops loading them on Mar 1, 2027 (shopify.dev changelog). App embed blocks replace them, and web pixels replace tags that only collect analytics. Ask each app's developer now, so you are not replacing apps in a hurry in February.
Is Shopify Flow available on Basic?
Yes. Flow is free on Basic, Grow, Advanced and Plus; Send HTTP Request needs Grow or above, and tasks created by custom partner apps need Plus (Shopify Help Center, read Oct 20, 2026). Most of the starter workflows in this guide work on Basic.
Can Sidekick replace apps?
Sometimes. Shopify says it can "generate custom apps to help you manage your store," and it presents changes for your review before applying them (Shopify Help Center, read Oct 20, 2026). Test anything it builds before relying on it. A custom app it generates still needs an owner and a test plan, like any other app.
Sources12 sources
- 01shopify.devchecked Oct 20, 2026Primary
- 02help.shopify.comchecked Oct 20, 2026Primary
- 03shopify.devchecked Oct 20, 2026Primary
- 04help.shopify.comchecked Oct 20, 2026Primary
- 05shopify.devchecked Oct 20, 2026Primary
- 06help.shopify.comchecked Oct 20, 2026Primary
- 07help.shopify.comchecked Oct 20, 2026Primary
- 08help.shopify.comchecked Oct 20, 2026Primary
- 09help.shopify.comchecked Oct 20, 2026Primary
- 10changelog.shopify.comchecked Oct 20, 2026Primary
- 11apps.shopify.comchecked Oct 20, 2026Primary
- 12apps.shopify.comchecked Oct 20, 2026Primary
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