postitif.com is the postmaster knowledge base of BounceZero Ltd, a UK company that operates one of the busier email validation and delivery platforms in Europe.
postitif.com is published and maintained by BounceZero Ltd, a private limited company registered in England and Wales (Company No. 17153835) with its registered office at 66 Paul Street, London EC2A 4NA. Our flagship product, BounceZero, is an email verification and deliverability platform used by senders ranging from solo founders to enterprise marketing teams.
We have been running production mail infrastructure since 2023. Our network sends transactional and verification traffic across more than a hundred dedicated IP addresses, multiple data centres in Europe and North America, and a custom-built MTA stack that handles millions of messages per month.
Email is, paradoxically, both the oldest and most poorly understood part of the modern internet stack. A developer can spin up a database cluster in minutes, but ask the same person to explain why their welcome email lands in spam and the answer is usually "I don't know — SendGrid said it was sent." The gap between "the SMTP server returned 250 OK" and "the message reached the inbox" is enormous, and most of the documentation that exists is either marketing material from email service providers or fragmented forum posts from a decade ago.
postitif.com is our attempt to close that gap. Every guide on this site is written by someone who actually operates the infrastructure they are describing — not a content marketer, not an SEO writer, and not a large language model rephrasing Wikipedia. When we explain how DMARC alignment works, the explanation comes from having debugged real alignment failures in production. When we describe an IP warmup schedule, it is the schedule we actually use.
The team behind BounceZero has hands-on experience with:
We don't pretend to know everything — deliverability is a moving target and the major mailbox providers change the rules without warning — but everything published here reflects what is actually working today on production traffic.
Every article goes through a simple process. A member of the postmaster team writes a first draft based on real-world cases they have handled. Another engineer reviews it for technical accuracy, runs every code snippet and DNS example, and verifies that any third-party tool we recommend still behaves as described. We update articles when something changes: when Gmail rolled out its bulk-sender requirements in February 2024, for example, we revised every guide that touched authentication within a week.
If you find a mistake or something out of date, please email postmaster@bouncezero.io — corrections from working postmasters are always welcome.
postitif.com is funded by BounceZero, but the guides are written to be useful regardless of which validation or delivery vendor you use. You will see references to BounceZero where relevant, but we do not pretend that ours is the only solution. Where another tool is better suited to a job — MXToolbox for one-off DNS lookups, Postmark for transactional sending under a hundred thousand messages a month, or Postfix for self-hosting — we will say so.