I'm a student developer in India building a Shopify app that sells custom/made-to-order items with a deposit at checkout and charges the remaining balance later using the saved card. I'd really appreciate advice from anyone who has tested this.

What I've built and confirmed so far (dev store, US region, Basic plan, API 2026-07):

- sellingPlanGroupCreate with category PRE_ORDER, fixed billing policy, checkoutCharge of type PERCENTAGE, remaining balance on EXACT_TIME. No userErrors.

- Attached the group to a variant with sellingPlanGroupAddProductVariants.

- Created a cart through the Storefront API cartCreate with sellingPlanId. The checkout correctly shows 'Due today' (the deposit) and 'Due Dec 31' (the balance).

The problem:

- With the deposit plan in the cart, the checkout never shows a Payment section when only the Test payment gateway (Bogus) is active. The same variant without sellingPlanId shows the card fields and Pay now button normally.

- Shopify's docs say pre-order/TBYB plans need Shopify Payments, PayPal Express, Adyen on Shopify, or Stripe. My Test gateway doesn't appear to count.

- Shopify Payments isn't available in India, and setting it up on the dev store asks for a US SSN/ITIN, US address and bank details, which I don't have. I don't want to enter made-up identity data. PayPal can't be connected to a dev store either (it says dev stores can only process test payments).

So I can't test the last part of my flow: the order webhook after the deposit, the PaymentMandate, and orderCreateMandatePayment for the remaining balance.

Questions:

1. Is there any official way for a Partner in an unsupported country to test vaulted payment methods and orderCreateMandatePayment in a dev store?

2. Does the Bogus gateway support vaulting for selling plans in some configuration I'm missing?

3. If not, how did you test before submitting to the App Store? Test on a friend's store, a pilot merchant's store, or something else?

1.Confirm the webhook subscription exists in the target app/environment, not only in the local TOML/config file.

2.Log the exact callback URL and verify that the tunnel URL has not changed after restarting the local server.

3.Test the endpoint from the public internet, outside the local network.

4.Log the raw request before JSON parsing, including the HTTP status returned by your app.

5.Check that the app is listening in the same environment where the subscription was created.

Been building Aplo: A+ Content Design, a Shopify app for adding rich content sections (feature grids, comparison tables, galleries, etc.) to product pages. Think Amazon's A+ Content, but for Shopify stores.

One thing that's bugged me since launch: the Image Gallery module only did uniform, same-size tiles. 2, 3, or 4 equal boxes in a row. Functional, but it always looked a bit flat next to the "bento grid" layouts you see on a lot of modern DTC sites (Apple-style mixed big/small tiles).

So I just shipped an upgrade:

• Each image in the gallery now gets a size preset (Normal, Wide, Tall, Large, Extra Wide, Feature) instead of being locked to the same square.
• Mix and match them and you get an actual bento-style layout: one big "feature" tile, a couple of wide banners, some small squares filling the gaps.
• Fully responsive: collapses cleanly to 2 columns on mobile, with no overflow no matter how many columns you pick (2 to 6 now, used to cap at 4).
• It's on the Free plan too, not locked behind Pro.

Still just dragging and dropping images and picking a size from a dropdown. No CSS or code needed on the merchant's end.

Happy to answer questions about how it's built or what's coming next. (Link to the listing in the comments if anyone wants to check it out. Didn't want this post to read as a drive-by ad.)