How to call rest API without merchant's access token?

Retired Boards Appdev Graphql Basics And Troubleshooting
1

I’m trying to make a product review app which is when the customer reviewed on product, it updates metafield of product. and show that data in metafields.

I’d like to set metafields when customer add review on product.

but my app can’t set data on metafields without merchant’s access token.

I want to make it automatic updates app, even merchant doesn’t do anything

2

Get your own access token, specifically for your app and store, and use it instead. The token can be generated during app installation - https://help.shopify.com/en/api/getting-started/authentication/oauth

3

Thanks for answering me,

I already did OAuth to get access token for accessing shop’s data and It works

but the app can access to shop’s data only when user open the app.

The thing I want to try is while user is not on my app, my app access to user’s shop data and read, modify

Is there any api or solution?