Nordica Bulk

Bulk edit, import and export for Shopify, by Variegata Nordica.

Edit prices, tags, stock, SEO and metafields across many products at once, with a preview of every change before it’s applied.
Import and export CSV and Excel files. Rows with a problem are explained in plain words; the good rows still go ahead.
Every job is backed up first and can be undone with one click.
Scheduled jobs, such as sale prices that start and end on their own.
Two-way sync with a Google Sheet in your own Google Drive. The app can only open the spreadsheet it creates for you.

Google Sheets

When you connect Google, Nordica Bulk asks for your email address and access to only the files it creates (the “drive.file” permission). It creates one spreadsheet with your products, reads it at each sync, and writes your Shopify changes into it. It can’t see or change anything else in your Drive. You can disconnect at any time in the app, or in your Google Account’s security settings.

Install it from the Shopify App Store, then open it from Apps in your Shopify admin.