Add one-click unsubscribe to marketing email

• You send newsletters, product updates, promotions or any other email that isn't strictly transactional.
• You send to Gmail or Yahoo addresses in volume (which is almost everyone).

• In the US, CAN-SPAM requires a clear way to opt out, honoured within 10 business days, and a valid postal address in every commercial email. Canada's CASL and the UK's PECR also require a working unsubscribe in every marketing message.
• Since 2024, Gmail and Yahoo require bulk senders to support one-click unsubscribe through the List-Unsubscribe and List-Unsubscribe-Post headers, to process unsubscribes within two days, and to authenticate mail with SPF, DKIM and DMARC. Senders who don't comply see their mail go to spam or be rejected.
• Making unsubscribing hard pushes people to press 'Report spam' instead, which hurts every email you send, including password resets.

• Which emails are marketing and which are transactional (receipts, password resets and security alerts are transactional).
• Your email provider (Resend, Postmark, SendGrid, Kit, Loops or similar) and whether it adds unsubscribe headers for you.
• Your business's postal address, if you send to US recipients.

Copy it into your AI builder. Fill in anything in [brackets] first, and review every change before you ship it.

Make unsubscribing work properly for every marketing email this app sends. Transactional email (receipts, password resets, security alerts) is out of scope and must keep working for unsubscribed people.

1. CLASSIFY
List every email the app sends and mark it marketing or transactional. Anything promoting a product, offer or newsletter is marketing.

2. LINK IN EVERY MARKETING EMAIL
- A visible "Unsubscribe" link in the footer, plus the sender's business name and postal address.
- The link carries a signed token (HMAC of the email or user id) so it can't be guessed or used to unsubscribe someone else.

3. HEADERS
- Add List-Unsubscribe with an https URL (and a mailto address if the provider supports it).
- Add List-Unsubscribe-Post: List-Unsubscribe=One-Click.
- If the email provider can add these itself, use its built-in feature instead and confirm it's on.

4. THE UNSUBSCRIBE ENDPOINT
- POST (what mail apps send for one-click): unsubscribe immediately, no login, return 200.
- GET (a person clicking the link): show a page with one "Unsubscribe" button. Don't unsubscribe on GET, because email security scanners open links automatically.
- Offer choices only after the unsubscribe (for example "Get monthly updates instead"), never as a hurdle before it.

5. RECORD AND RESPECT IT
- Store the opt-out with a timestamp, and check it before every marketing send. Sync it to the email provider's suppression list if you use one.
- Process it immediately; never later than 2 days.

6. AUTHENTICATION
- Check the sending domain has SPF, DKIM and a DMARC record, and tell me what's missing.

When you're done: list every file you changed, explain each change in one line, and give me a step-by-step test for each numbered item above. Don't change anything unrelated.

• Unsubscribing on GET, so security scanners unsubscribe people who never clicked.
• Requiring a login or a reason before unsubscribing.
• Unsubscribing from one list while other marketing keeps arriving.
• Blocking transactional email for unsubscribed users, which breaks password resets.

1. 1Send yourself a marketing email at a Gmail address: Gmail shows its own Unsubscribe link next to the sender name.
2. 2In Gmail, open the message's menu → Show original: the headers include List-Unsubscribe and List-Unsubscribe-Post, and SPF, DKIM and DMARC show PASS.
3. 3Click the footer link: one confirmation step, then you're unsubscribed.
4. 4Trigger the next campaign: you don't receive it, but a password reset still arrives.

• FTC: CAN-SPAM Act compliance guide
• Google: Email sender guidelines
• RFC 8058: one-click unsubscribe

General guidance for common problems, not legal advice. Whether a rule applies depends on where you operate, who your users are and the size of your business.