Stop link previews approving your n8n drafts
If your n8n workflow emails an approver a link like /approve?id=123, be careful. Email security scanners and Slack or Teams link previews open links automatically. A webhook that approves on GET can be triggered before a person has seen the draft.
Split it into two steps:
1. The link opens a review page (GET) that changes nothing. It shows the draft and its hash. 2. The decision is a POST from a button on that page, carrying a per-approver token. Set the decision webhook to POST only, and reject a missing, forged or reused token.
Do the same for a Wait node set to resume on webhook: choose POST, so a preview can't resume the run.
The Approval Gate, n8n pack (US$29) is built this way. In our tests on n8n 2.43.7, repeated GETs and a HEAD of the review link changed nothing.