You stay in control of every change
- Scanning is read-only. Nothing in your account changes until you review a fix, tick “I’ve checked these values” and press Apply.
- Fixes are isolated. By default, fixes go into a separate supplemental source called “Merchant Guard fixes”. Your own feed isn’t edited, and deleting that source in Merchant Center removes every fix at once.
- Every change is logged with the value it replaced, and can be undone in one click.
- Built-in safety checks refuse risky writes, such as writing to a feed owned by another app, applying values that fail Google’s format rules, or barcodes with an invalid check digit.
- The assistant can’t act alone. It can read your account to answer questions, but changes it suggests always come to you as a card to review.
Access to your Google account
- Merchant Guard uses Google’s official sign-in and the Merchant API. We never ask for, see or store your Google password.
- In Chrome, Google sign-in tokens are managed by Chrome itself. Our servers use your token only for the request you make, and check it belongs to your Merchant Guard account.
- 24/7 monitoring is a separate permission you grant on the website. Its long-lived token is encrypted with AES-256-GCM, used only to run your scheduled checks, and revoked with Google when you disconnect monitoring or delete your account.
- Shopify access is read-only and its token is encrypted in the same way.
- You can remove Merchant Guard’s access at any time from your Google account.
Protecting our service
- All traffic uses HTTPS. The website sends strict security headers, including a content security policy that only allows our own scripts.
- Sessions are signed and can be ended everywhere at once from your account. Website sessions use secure, HTTP-only cookies.
- Our API only accepts browser requests from the published Merchant Guard extension and our own website, and every account action needs a signed session.
- Stripe and Shopify webhooks are verified by signature before we act on them. Card details never reach our servers.
- The page checker that reads product pages blocks private and internal network addresses, re-checks every redirect and limits response sizes.
- Requests are rate limited to prevent abuse, and administrative actions are recorded in an audit log.
Your data
We keep as little as we can. Your product catalogue stays in Google and your browser, and we delete data on a fixed schedule. The privacy policy lists what we hold and for how long. You can download or delete your data from your account at any time.
Reporting a vulnerability
If you think you’ve found a security problem, please email support@merchant-guard.co.uk with “Security report” in the subject. Include steps to reproduce it and please don’t access other people’s data or disrupt the service while testing. We’ll acknowledge your report within two working days, keep you updated, and credit you if you’d like once it’s fixed.