Dev Server is not starting

Shopify CLI and Libraries
,
1

I have reproduced the issue on the latest CLI version.

Yes, I am on the latest version

I have searched existing posts and this report is not a duplicate.

Yes, this isn’t a duplicate

In which of these areas are you experiencing a problem?

App

Expected behavior

DEV server should start

Actual behavior

DEV server isnt running

Reproduction steps

shopify app dev

Verbose output

12:05:23 │               app-preview │ ❌ Error
12:05:23 │               app-preview │ └  Cannot read properties of null (reading '0')

────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
│ (d) Dev status │ (a) App info │ (s) Store info │                                                                                                                      (q) Quit

 ❌ Error updating app preview


12:05:23 │                extensions │

12:05:23 │               app-preview │ ❌ Error
12:05:23 │               app-preview │ └  Cannot read properties of null (reading '0')

────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
│ (d) Dev status │ (a) App info │ (s) Store info │                                                                                                                      (q) Quit
12:05:23 │                extensions │

12:05:23 │               app-preview │ ❌ Error
12:05:23 │               app-preview │ └  Cannot read properties of null (reading '0')

────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
12:05:23 │                extensions │

12:05:23 │               app-preview │ ❌ Error
12:05:23 │               app-preview │ └  Cannot read properties of null (reading '0')
12:05:23 │                extensions │

12:05:23 │               app-preview │ ❌ Error
12:05:23 │                extensions │

12:05:23 │                extensions │

12:05:23 │                extensions │
12:05:23 │                extensions │
12:05:23 │                extensions │

12:05:23 │                extensions │

12:05:23 │               app-preview │ ❌ Error
12:05:23 │               app-preview │ └  Cannot read properties of null (reading '0')

Operating system

Windows 10

CLI version

3.87.1

Shell

Git Bash

Nodejs version

20.16.0

2

Hi! Could you run shopify app dev --verbose and share the output? Which extensions include your app? Does it fail if you create a new app?

3

Hi! I’m experiencing the same issue with Shopify CLI version 3.87.1: app-preview │ Cannot read properties of null (reading ‘0’) when I used shopify app dev. In my case I have an ui_extension in the thank you page.
If I uninstall the current version and install an earlier one it works again:

npm uninstall -g @shopify/cli
npm install -g @shopify/cli@3.86.1
4

Hi! I found a solution. If you update Node to the latest version (v24.11.1), it works with the latest CLI version.

5

If anyone else experiences this issue, --verbose output would be great so that we can diagnose the problem on other supported node versions.

6

Having the same issue, switched back to shopify/cli version 3.86.1 like Raquel suggested and that seemed to fix the issue. I can send you the verbose output, do you have contact details where I can send this to you privately to protect sensitive company data.

7

We have confirmed that this issue appears to be specific to Node 20.15 and 20.16, using Node 20.17 should resolve the issue on the latest Shopify CLI.

We are considering our options for a fix.