How to use Subi subscriptions inside the Rebuy Smart Cart drawer

If you use Rebuy Smart Cart as your cart drawer, your Subi subscription plans work automatically inside it. This guide explains how the integration works, how to enable it, and how to troubleshoot common issues.

How It Works

Subi and Rebuy integrate through Shopify's native Selling Plans. There is no direct connection between the two apps — Shopify acts as the bridge:

Subi creates selling plans for your subscription products (Subscribe & Save, prepaid, etc.)
Shopify stores the plans on your products and variants
Rebuy reads the plans from Shopify and displays subscription options inside the Smart Cart drawer
When a customer toggles "Subscribe & Save" in the cart, Rebuy updates the cart through Shopify's standard Cart API
At checkout, Shopify processes the subscription order and Subi manages the recurring contract

This means you do not need to install any extra connector or configure a direct API between Subi and Rebuy.

Prerequisites

A Subi subscription plan assigned to at least one product
Rebuy Smart Cart installed and enabled on your store
Selling plans must be synced in Rebuy (see next section)

Step 1: Enable Selling Plans in Rebuy

Open the Rebuy dashboard
Go to Settings > Integrations (or Settings > Status)
Look for Selling Plans and make sure it is enabled
If you just set up your Subi plans, click Resync next to Selling Plans to pull the latest data from Shopify

Rebuy syncs selling plan data from Shopify periodically. If you recently created or changed a Subi plan and it's not showing in the cart, try resyncing manually.

Step 2: Enable "Switch to Subscription" in Smart Cart

In the Rebuy dashboard, go to Smart Cart > Settings
Look for the "Switch to Subscription" toggle and enable it
Choose how you want subscription options to display:
- Inline toggle — shows "Subscribe & Save" directly on each eligible line item
- Frequency selector — lets customers pick delivery frequency (e.g., every 30, 60, 90 days)
Save your changes

Step 3: Test the Integration

Go to your storefront and add a product with a Subi subscription plan to the cart
Open the Rebuy Smart Cart drawer
You should see a "Subscribe & Save" option on the product (with the discount amount)
Toggle it to subscription — the price should update to reflect the subscription discount
Select a delivery frequency if multiple options are available
Proceed to checkout and verify the subscription is applied

What the Customer Sees

When a product has a Subi subscription plan, the Rebuy Smart Cart displays:

One-time vs. Subscription toggle — customers can switch between purchasing once or subscribing
Subscription savings — the discount percentage or amount (e.g., "Save 15%")
Delivery frequency — a dropdown or selector to choose how often they receive the product
Updated pricing — the line item price updates instantly when switching to subscription

Troubleshooting

Subscription option not showing in the cart drawer

Make sure the product has an active Subi selling plan assigned to it
In Rebuy, go to Settings > Status and click Resync next to Selling Plans
Verify that "Switch to Subscription" is enabled in Rebuy Smart Cart settings
Clear your browser cache and try again

Price not updating when toggling subscription

Check that your Subi plan has a discount configured (percentage or fixed amount)
Resync selling plans in Rebuy — the pricing data may be stale

Subscription not appearing at checkout

Ensure you are using Shopify Checkout (not a custom or third-party checkout)
Verify the product variant still has the selling plan attached in Subi > Selling Plans

Changes to Subi plans not reflected in Rebuy

Shopify does not send real-time notifications when selling plans change. After editing a plan in Subi, always resync in Rebuy (Settings > Status > Resync)
Wait a few minutes — Rebuy also syncs automatically on a schedule

Frequently Asked Questions

Do I need to pay extra for this integration?

No. The integration works through Shopify's built-in Selling Plans API. Both Subi and Rebuy read from Shopify — there is no extra fee for connecting them.

Does this work with other cart drawer apps (iCart, UpCart, Slide Cart)?

Yes. Any cart drawer app that supports Shopify Selling Plans will work with Subi automatically. The setup steps may differ — check the cart app's documentation for how to enable selling plan display.

What if I want subscription options without Rebuy?

Subi's native cart drawer subscription widget is coming soon. It will let you show subscription options inside your theme's built-in cart drawer — without needing Rebuy or any other cart drawer app.

Does the subscription contract get created by Subi or Rebuy?

By Subi. Rebuy only handles the cart display. When the customer checks out with a subscription, Shopify creates the order and Subi manages the subscription contract, recurring billing, and customer portal.

How the Data Flows

Step	What Happens	Who Does It
1	Selling plans are created and assigned to products	Subi
2	Product and variant data includes selling plan allocations	Shopify
3	Cart drawer reads selling plans and shows subscription toggle	Rebuy
4	Customer toggles to subscription; cart is updated via Cart API	Rebuy + Shopify
5	Customer completes checkout with subscription	Shopify
6	Subscription contract is created and managed	Subi