Effective email deliverability hinges on several authentication methods, primarily SPF, DKIM, and DMARC, which help manage and secure the sending and receipt of emails. SPF authenticates by verifying the IP addresses allowed to send emails for a domain, helping to reduce spam. DKIM adds a layer of security by using encryption to ensure that emails are not altered in transit, akin to verifying a signature on a letter. DMARC builds on SPF and DKIM by allowing senders to specify policies and receive feedback on email authentication, reducing spoofing attacks and improving overall deliverability. These methods are essential for maintaining the integrity and reliability of email communications, especially for businesses where email deliverability is crucial. Companies like Nylas offer integrated solutions to streamline these processes and enhance deliverability across all email service providers.