Spam notifications
Some inbox providers offer a feedback loop (FBL) that reports spam complaints to senders. A spam complaint occurs when a subscriber clicks the spam or junk button in their inbox. FBLs help senders keeping a clean list. Senders should use spam complaints received by FBL's to listen to their subscribers and take action if there are complaints.
Senders with high spam complaint rates will typically see more inboxing and deliverability issues. It's important to learn from the complaints you receive because they can help senders evaluate underlying issues with sending frequency and content. Senders can't control how recipients react to messages, but you can control the manner in which subscribers sign up to hear from you and how you communicate to those subscribers.
When someone signs up for your email program, they enter into a relationship with you. To building a strong relationship with recipients and mitigating spam complaints, follow best practices and don't abuse subscribers' expectations.
Twilio enrolls all users for any major inbox provider that offers a feedback loop. Twilio consumes the information returned from the inbox provider's FBL and generate a spamreport event using the user's event webhook. Additionally, Twilio will add the reporter's address to the user's suppression list to aid senders in having the best possible reputation.
While Twilio enrolls users in FBLs, not all inbox providers have feedback loops. Apple and Google are examples of providers that don't offer traditional FBL's. Twilio consumes FBLs from most inbox providers that offer them, including Microsoft, Yahoo, and domains using the Validity FBL.