Need help deploying my app / proxy with the app

Technical Q&A

Topic summary

A developer encountered deployment issues with a custom Shopify app designed for their own store. The app reads product information, fetches images from mega.nz, converts them to base64, sends them to a print-on-demand API, and updates product images.

Core Problem:

  • App worked during local development (shopify app dev) but failed after deployment (shopify app deploy)
  • Received 404 errors when calling /apps/mockup/generate-mockup endpoint
  • Confusion about correct API_URL configuration and hosting requirements

Key Clarifications Provided:

  • shopify app deploy does NOT deploy the web app itself—separate hosting is required
  • App proxies and app embeds are distinct concepts that shouldn’t be confused
  • Local development differs from remote/hosted deployment

Resolution:
The original poster confirmed they resolved the issue but did not provide specific details about their solution. A follow-up request was made asking them to share how they fixed it for future community members facing similar problems.

Status: Resolved (solution details not documented)

Summarized with AI on October 23. AI used: claude-sonnet-4-5-20250929.
1

Hello! Idk if app posts are allowed here but I’ll try my luck. Im struggling with deploying my app currently.

Short description of app:
First and foremost this app is only supposed to be used for my own store, no one else will be using the app.

Function of app:
Reading information from the product page > mapping it to SKU’s + getting image from mega.nz > Converting image to base 64 > sending base64 to POD provider API > Receiving back image > updating image on product page.

Description of issue:
When doing shopify app dev it works perfectly fine. But with shopify app deploy its not working. First thing I’m wondering is if I need separate hosting for this?
If I do, then do you know any free one?

If I don’t, then why is it not working when I do shopify app deploy. The app is installed on the store, and toggled on as an app embed. I can get to the step of converting the image to base64, but after that I get an error 404:

:white_check_mark: Found image with selector: .product-media img read-product.js:25:17

:outbox_tray: Calling API: /apps/mockup/generate-mockup read-product.js:176:15

:inbox_tray: Response status: 404 read-product.js:190:15

:white_check_mark: Found image with selector: .product-media img

Sorry for the emojis, doing this using AI and AI loves emojis.

This step works perfectly fine when doing shopify app dev because when I do shopify app dev it generates a url like “https ://vernon-birmingham-reflect-trim.trycloudflare.com/apps/mockup”. So I change my const API_URL to: “https ://vernon-birmingham-reflect-trim.trycloudflare.com/api/generate-mockup”; (it didnt work with “/apps/mockup/” for some reason, i dont remember why but worked with “/api/generate-mockup”. But then when trying to deploy I dont get a url, and i dont know what the API_URL should be, ive tried these:

const API_URL = “/apps/mockup/generate-mockup”;
const API_URL = “https ://domain.com/apps/mockup/generate-mockup”;
const API_URL =”https ://domain.com/api/generate-mockup”;

But none worked.

i also dont know if the 404 issue is only because of this or also because of my shopify.app.toml. Idk what that should look like, before when using shopify app dev it had only “example. com”, now ive tried to change it to “domain. com”. The fields im not sure about are: “application_url” “redirect_url” and “[app_proxy]” url. With domain. com there I still get error 404. (And for [“app_proxy”] url it was never domain. com it was “/apps/mockup”

As you can probably tell I’m a bit lost.

Since I dont rly know anything about the topic, I also dont really know what information to include in this post, so hope I’m not too all over the place. If you need any more information please tell me what you need.

Thanks for any and all help!

2

Did you read the friendly manual

app deploy
…
This command doesn’t deploy your web app. You need to deploy your web app to your own hosting solution. shopify docs:
app deploy.

When you hit a beginners problem just ask yourself how many times has this been asked then google it.

:hourglass_done: :bomb: If you’ll be developing for some time you should really read a guide like this one to improve your troubleshooting communication skills or your gonna burn a ton of your lifetime and others on ambiguity.

Step back and re-read all the relevant docs carefully you mixing things up

Or any of the literal thousands of tutorials online for app proxy’s to get you past the deploy step then to the real questions.

Join the .dev forums for dev stuff, or if partner join the shopify slack

One is local , the other is remote i.e. hosting.

“hosting” is waaay to vague and broad of a term, near useless.
Everyone stack is different define your needs actual needs then googling.
Like if i say gadget.dev but your using ruby that’s a waste of time.

app proxies are NOT app embeds.
They are two separate concepts and areas of the docs for a reason
a proxy is to your app, an embed is small amount of FRONTEND code for themes that shopify stores .
Step back and make the time investment to actually re-read all the relevant docs carefully your mixing things up so wasting your own time in confusion.

oh well that’s that then, good luck.

1 Like
3

Got it to work thanks!

4

For future readers of the community you joined for help , can you describe how you solved it?
You can mark my post or even your description as the solution