Unsubscribe UX vs deliverability
A visible, frictionless unsubscribe reduces complaints and throttling risk. RFC 8058 One‑Click is a strong trust signal: clients can offer native UI to unsubscribe without abuse.
Verify headers
Check presence of List‑Unsubscribe and List‑Unsubscribe‑Post: List‑Unsubscribe=One‑Click. Automated checks should not dereference URLs.
Design guidelines
- Put an unsubscribe link above the fold and in the footer
- Use a single‑step HTTPS endpoint (no login); idempotent POST
- Confirm opt‑outs immediately; show clear status
Anti‑abuse
- Rate‑limit and token‑protect endpoints
- Disallow non‑https schemes (e.g., file://, gopher://, 169.254/metadata)
- Never follow unsubscribe links in bots or monitors