The Use dynamic link action takes one of your Dynamic Links and overlays runtime parameters on it — line items from the trigger, a customer — to produce a per-trigger customized URL. It doesn't send anything on its own; chain it into Send Checkout Link to deliver the URL by email.
For an overview of how Checkout Links works with Shopify Flow, see Shopify Flow. For Dynamic Links themselves, see Dynamic.
Before you start
You need an existing Dynamic Link to use. In Checkout Links, open the link editor and turn on the Dynamic option for the link you want to customize at runtime. Only links marked Dynamic show up in the picker.
When to use it
Use Use dynamic link when the link you want to send is mostly the same every time but needs a per-trigger tweak — usually the cart or the customer. For example:
After an order, send a one-click reorder link with the order's line items already in the cart
Send the same VIP-exclusive link to a whole segment, but pre-fill each recipient as themselves at checkout
Build a "complete your set" upsell where the cart starts with the customer's recent purchase plus a complement
How to add the action to a Flow
In Shopify, open Flow and click Create workflow
Pick any trigger — for example Order created
Click Add action and choose Checkout Links > Use dynamic link
Click Configure to open the link picker and pick a Dynamic Link
Fill in Cart items and Customer in the Flow editor (see below)
Add a Send Checkout Link step after it, and set its Link field to the URL produced by this step
Action settings
Link — Picked in the configuration page. Only Dynamic Links appear in the picker. If you don't see any, open Checkout Links and turn on Dynamic on the link you want
Cart items — Variants to put in the cart. Format: variantId:quantity:sellingPlanId, separated by commas. The selling plan is optional, so 1001:2 works for a regular product and 1001:2:abc attaches a selling plan. You can drag a Flow variable here, like the line items from an Order trigger. Leave blank to use whatever cart the Dynamic Link was already set up with
Customer — The customer to pre-fill at checkout. Usually the customer from the trigger
What it outputs
The action produces:
A URL — the full checkout link with the cart and customer applied, ready to email
A shortcode — the underlying Dynamic Link's shortcode, in case you want to reference it elsewhere
Drag the URL into the Link field of Send Checkout Link to send it.
Example: per-order reorder link
Trigger: Order created
Use dynamic link — pick your "Reorder" link, set Cart items to the order's line items, and Customer to the order's customer
Send Checkout Link — set Customer to the order's customer and Link to the URL from step 2
Tips
Empty Cart items just means "use the link's saved cart" — handy when you only want to customize the customer
If the picker shows no links, the issue is the Dynamic toggle in the link editor, not the action
Use dynamic link doesn't send anything by itself — pair it with Send Checkout Link