Deployment to Heroku: Missing Shopify API Key

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Topic summary

Main issue: Deploying a Shopify CLI-generated app to Heroku failed due to missing environment variables, leading first to app crashes and then to a Shopify frontend build error.

Key events:

  • Initial crash fixed by manually adding the HOST environment variable in Heroku (not mentioned in the official docs).
  • Subsequent error: browser showed a Shopify error; logs warned, “Building the frontend app without an API key… Set the SHOPIFY_API_KEY environment variable.”
  • Clarification: Variables can be set via Heroku Dashboard (Settings > Config Vars), the Heroku CLI (heroku config:set -a …), or in heroku.yml under build.config.

Resolution (most recent update):

  • Adding SHOPIFY_API_KEY to heroku.yml (build.config) solved the build issue, and the app now runs in production.

Notes:

  • A screenshot of the Shopify error was referenced; logs were central to identifying the missing SHOPIFY_API_KEY.
  • The participant highlighted gaps in Shopify’s Heroku deployment docs (no mention of HOST and unclear guidance on setting SHOPIFY_API_KEY during build).

Status: Resolved; no remaining open questions.

Summarized with AI on December 19. AI used: gpt-5.
1

Hi all,

Incredibly frustrating, i’m following the Shopify docs for deploying an app to Heroku for an app which was scaffolded and build with the Shopify CLI.

I’m following these docs:

https://shopify.dev/docs/apps/launch/deployment/deploy-web-app/deploy-to-heroku

And more generally for deploying to a hosting service:

https://shopify.dev/docs/apps/launch/deployment/deploy-web-app/deploy-to-hosting-service

Initially the app would just crash immediately and a Heroku error would display. After reading other people’s issues with this, it turned out to be that the docs don’t actually tell you to set up a HOST env variable on Heroku. Literally no mention of the HOST env variable whatsoever in the docs, so I added it via Heroku web admin, and suddenly the app no longer crashes! Hurray!

However, the current issue I have is that I now see a Shopify error as follows:

Mat_Brummitt_0-1726913479107.png
Mat_Brummitt_0-1726913479107.png1316×302 21.9 KB

Additionally the logs show the following:

remote: Building the frontend app without an API key. The frontend build will not run without an API key. Set the SHOPIFY_API_KEY environment variable when running the build command.

I’ve followed the docs completely I just don’t understand what to do at this point. How do I “Set the SHOPIFY_API_KEY environment variable when running the build command” when this is all supposed to be handled by the CLI’s that are being used according to the docs?

Note: calling “shopify app env show” returns the expected environment variables and values.

Thanks for any advice

Mat

2

Did you set the variables in your heroku app via the CLI or the dashboard > settings > config vars?

Screenshot 2024-09-21 at 11.46.50 AM.png
Screenshot 2024-09-21 at 11.46.50 AM.png3086×1518 276 KB

heroku config:set -a 

in your heroku tml file you can also add it there:

```markup
build:
  docker:
    web: Dockerfile
  config:
    SHOPIFY_API_KEY:
1 Like
3

Thank you, thank you thank you!!!

It was updating the heroku.yml file that made it work for me:

config:
    SHOPIFY_API_KEY: 

I can't understand why this isn't documented on the page which describes how to deploy to Heroku!

Anyway thanks so much again, it's amazing to finally see my app hosted in a production environment and ready for deployment after so much hard work!

Mat