How strict are Apple filters on bulk senders?

Apple's filters show moderate strictness on bulk senders, applying traditional reputation and content filtering without the sophisticated engagement based personalization of larger providers. Bulk senders without established reputation face conservative filtering that errs toward protection.

iCloud's smaller market share means less publicly available data about their specific thresholds and triggers. Senders report that authentication compliance, clean sending history, and non spammy content are the primary factors influencing iCloud deliverability.

Apple does not publish bulk sender guidelines comparable to Gmail or Yahoo's recent requirements. However, following industry standard practices, proper authentication, low complaint rates, clean lists, and relevant content, generally produces acceptable results at iCloud. Problems are often resolved through the same fundamentals that work across providers.