We are most email providers have deliverability issues due to their approach of treating all customers equally, without taking care of shared IPs, using separate IPs for transactional and marketing emails, or proactively helping customers. In contrast, Postmark takes a different approach by not allowing bad senders into its platform, having multiple high-reputation IP pools, manually approving every account, monitoring spam complaint rates and bounce rates closely, sharing detected delivery issues with customers, and building an infrastructure to separate transactional and broadcast emails, resulting in 99% global delivery rates for both types of email.