Checkout Add-On

Attach practical companions to an order at checkout so buyers configure a complete purchase instead of returning later.

Pro moderate Funnel-Stage Offers

What it adds

The builder reads your catalog, fulfillment, and checkout source files to assemble a compact set of genuinely compatible add-ons — protection, expedited handling, accessories, or setup services — presented as selectable options that respect the buyer's chosen variant. It converts by solving completeness: the shopper is choosing configuration, not evaluating a new purchase, so relevance and quantity awareness matter more than persuasion. The conversion event is a higher-value completed order with add-ons correctly reflected in fulfillment.

What your builder is told to do

The actual instructions, in order.

1
Inspect the source files and build the compatibility map: which add-ons apply to which products, variants, quantities, and destinations, so nothing incompatible can ever be offered.
2
Limit the display to at most three add-ons ranked by attach relevance, since a longer list turns checkout into browsing and depresses completion.
3
Describe each add-on by the specific situation it prevents or the step it removes, in one line, with its price shown per unit and per order where quantity applies.
4
Make selection stateful and reversible: adding or removing updates the order total, tax, and shipping estimate inline, and the buyer can change quantity without leaving the step.
5
Position the add-on step after shipping selection and before payment, so totals shown at the payment step are final and no surprise cost appears after card entry.
6
Define layout: mobile renders add-ons as full-width cards with a single toggle each and a live total pinned to the bottom; tablet uses a two-up grid with the order summary above; desktop places add-ons in the main column with a persistent order summary that updates visibly on each change.
7
Propagate every selection into the fulfillment record — packing, service scheduling, or entitlement grant — and verify the downstream system receives it before considering the build complete.
8
Track per-add-on attach rate and revenue contribution independently, and suppress add-ons the buyer already owns or that were declined earlier in the same session.

Edge cases it handles

The things an agent skips when you only say "build a checkout add-on".

The buyer changes the base product after selecting add-ons: revalidate compatibility and remove now-invalid selections with a visible notice.
Quantity mismatch, such as one accessory for three units: prompt for quantity rather than silently assuming one.
The destination excludes an add-on for shipping or regulatory reasons: hide it rather than failing at payment.
A service add-on requires scheduling: capture availability at checkout or defer with a clear follow-up promise.
Partial refund of the base order: define whether attached add-ons are refunded with it.

Definition of done

Your builder is required to check every one of these before reporting the work finished.

Only compatible add-ons appear, validated against rules in the source files.
No more than three options are shown, each with a one-line reason and clear pricing.
Selection updates total, tax, and shipping inline before the payment step.
Mobile, tablet, and desktop each keep the live order total visible during selection.
Selections propagate correctly into the fulfillment or entitlement record.
Attach rate is tracked per add-on, with owned and declined items suppressed.
The builder lists the source files defining compatibility and fulfillment, and any unresolved variant assumptions.

Related offer files

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How it works

1

Copy the link

Grab the Markdown blueprint URL for this offer type.
2

Give it to your builder

Paste it into Claude Code, Cursor, Codex, or whatever AI builder is already working in your app.
3

It maps, then builds

Your agent reads the blueprint first, then builds the offer into your app around the product, audience, and stack.

Works with your stack

These blueprints are written to adapt. They tell the agent to detect your framework, match your existing design system, and use your source files instead of guessing the offer.

Need it tighter than that? Customize the offer file and tell it exactly which source docs and stack to use.