purchase.checkout.block.render UI extension never appears in checkout editor Apps panel after install

Extensions
1

## Summary

A checkout UI extension targeting `purchase.checkout.block.render` shows as **“Available for Checkout”** in the Partners Dashboard but **never appears in the checkout editor Apps panel** after a fresh install on a dev store. Shopify Support has escalated this — posting here in parallel per their recommendation.

## App & Extension Details

- **App:** Local Pickup Auto Discount

- **Client ID:** `6ace612a9fc1045415b51799c39d14e1`

- **Active version:** `local-pickup-auto-discount-46` (status: Active + Released)

- **Dev store:** `pickupdiscount-app.myshopify.com`

- **CLI version:** 3.94.3

## Extension Config (shopify.extension.toml)

```toml

api_version = “2026-04”

[[extensions]]

name = “pickup-discount-ui”

handle = “pickup-discount-ui”

type = “ui_extension”

uid = “26f7f38e-9ac8-2b3a-1f8e-3ccf28ebd68cd3a74ce6”

[[extensions.targeting]]

module = “./src/index.jsx”

target = “purchase.checkout.block.render”

[extensions.capabilities]

api_access = true

[[extensions.metafields]]

namespace = “pickup_discount”

key = “eligible”

```

## What We’ve Tried

- Fresh uninstall + reinstall of the app on the dev store

- Verified TOML matches CLI-generated template exactly

- Confirmed extension shows “Available for Checkout” in Partners Dashboard app settings

- Created a second fresh diagnostic extension (`test-ref`) via `shopify app generate extension` with the same target — it also never appears in the Apps panel

- Confirmed the store is on extensible checkout (not `checkout.liquid`)

- Confirmed the store is not on Shopify Plus (not required for `purchase.checkout.block.render`)

## Observed Behavior

After installing the app on the dev store, the checkout editor Apps panel shows:

> “Explore apps for checkout and customer accounts” — Added: 0

Nothing is listed. The `activatedExtensions` array in the checkout profile appears empty despite the app being installed and the version being Active + Released.

## Expected Behavior

The extension block should appear in the Apps panel and be draggable into the checkout layout.

Has anyone else hit this? Is there a known backend registration step that can silently fail? Any insight appreciated.

2

Shopify Plus is required to be able to place extensions in Checkout targets.

3

Thanks Kenza — that confirms exactly what we were seeing.

Checkout UI extensions never mount on Shopify Plus development stores — is private_access_tokens 401 expected on dev stores?

We have a checkout UI extension (purchase.checkout.contact.render-after) on a Shopify Plus development store. After full uninstall + fresh reinstall, the extension bundle loads from CDN (200 OK), but the extension never mounts — no console output, renderContextToken: null in the Proposal response on every load.

In both headless Chrome and a real Chrome browser, private_access_tokens?id=...&checkout_type=c1 returns 401 ERR_ABORTED. The 401 is coming from Shopify’s own checkout code, not our extension.

Is the Private Access Token (PAT) challenge expected to fail on Shopify development stores? If so, is shopify app dev (which uses a dev= URL bypass) the only supported way to test deployed checkout UI extensions on dev stores? And does this mean the extension will work correctly on a real merchant’s Plus store even though we can’t verify it on our dev store?