Standards
Exchanging email is straightforward thanks to the many standards (RFCs) that have enabled its worldwide adoption. If you're looking for independence, tech sovereignty, or to be able to tweak something to make your life easier, then configuring and managing your own mail server could be just what you need.
Tech sovereignty
When you manage your own infrastructure you have sovereignty over your email for your domains, you can be confident that you're in control of receiving, managing and sending your emails. Open source means you have access to the source code, you can see how it works and modify or update it if necessary.
There is ample help, both paid and free, for when you're looking for feedback, get stuck, unsure how to implement a feature, or just want the confidence to know your email is under your control.
The history of email
An email message is often cited as RFC 822, created in 1982. The concept of sharing messages can be easily traced back to 1973 with RFC 524 in "A Proposed Mail Protocol". It has since been superseded by a number of standards that define in much more detail how a message is sent between servers and how an email is constructed.
As much as an organisation might prefer a monopoly with hidden techniques, public standards enables everyone to share the benefits creating a much larger ecosystem, email is one of those global standards. Looking at that original RFC and following the links in "Document type" and you quickly realise there are many related standards, by way of example the 822 Document type is:
Document type
RFC - Internet Standard
August 1982
Obsoleted by RFC 2822
Updated by RFC 1123, RFC 1138, RFC 1148, RFC 2156, RFC 1327
Obsoletes RFC 733
There are standards for authenticating an email RFC 6376 (DKIM), authenticating a sender RFC 7208 (SPF), and in RFC 7489 combining them enabling more comprehensive Domain-based Message Authentication, Reporting, and Conformance (DMARC).
Standards
It's these agreed upon standards that enables the largest providers and the smallest independents to work together exchanging email across countries, languages and time zones.
The following is an incomplete list of standards (RFCs) that impact DBMail.
RFC 822
Obsoleted by RFC 2822.
Standard for the format of ARPA internet text messages https://datatracker.ietf.org/doc/html/rfc822
RFC 1939
Post Office Protocol - Version 3 https://datatracker.ietf.org/doc/html/rfc1939/
RFC 2033
Local Mail Transfer Protocol https://datatracker.ietf.org/doc/html/rfc2033
RFC 2045
Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies https://datatracker.ietf.org/doc/html/rfc2045
RFC 2046
Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types https://datatracker.ietf.org/doc/html/rfc2046
RFC 2047
MIME (Multipurpose Internet Mail Extensions) Part Three: Message Header Extensions for Non-ASCII Text https://datatracker.ietf.org/doc/html/rfc2047
RFC 2048
Multipurpose Internet Mail Extensions (MIME) Part Four: Registration Procedures https://datatracker.ietf.org/doc/html/rfc2048
RFC 2049
Multipurpose Internet Mail Extensions (MIME) Part Five: Conformance Criteria and Examples https://datatracker.ietf.org/doc/html/rfc2049
RFC 2060
The Internet Message Access Protocol, Version 4rev1 (IMAP4rev1) allows a client to access and manipulate electronic mail messages on a server. IMAP4rev1 permits manipulation of remote message folders,
called "mailboxes", in a way that is functionally equivalent to local mailboxes. IMAP4rev1 also provides the capability for an offline client to resynchronize with the server.
IMAP4rev1 includes operations for creating, deleting, and renaming mailboxes; checking for new messages; permanently removing messages; setting and clearing flags; [RFC-822] and [MIME-IMB] parsing; searching; and selective fetching of message attributes, texts, and portions thereof. Messages in IMAP4rev1 are accessed by the use of numbers. These numbers are either message sequence numbers or unique identifiers.
https://datatracker.ietf.org/doc/html/rfc2060
RFC 2086
IMAP4 Access Control List (ACL) Extension - See RFC 4314 below.
RFC 2184
MIME Parameter Value and Encoded Word Extensions: Character Sets, Languages, and Continuations https://datatracker.ietf.org/doc/html/rfc2184
RFC 2231
MIME Parameter Value and Encoded Word Extensions: Character Sets, Languages, and Continuations https://datatracker.ietf.org/doc/html/rfc2231
RFC 2798
Definition of the inetOrgPerson LDAP Object Class https://datatracker.ietf.org/doc/html/rfc2798
RFC 2822
Internet Message Format https://datatracker.ietf.org/doc/html/rfc2822
RFC 3463
Enhanced Mail System Status Codes https://datatracker.ietf.org/doc/html/rfc3463
RFC 3503
Message Disposition Notification (MDN) profile for Internet Message Access Protocol (IMAP) https://datatracker.ietf.org/doc/html/rfc3503
RFC 4314
IMAP4 Access Control List (ACL) Extension
The Access Control List (ACL) extension (RFC 2086) of the Internet Message Access Protocol (IMAP) permits mailbox access control lists to be retrieved and manipulated through the IMAP protocol.
This document is a revision of RFC 2086. It defines several new access control rights and clarifies which rights are required for different IMAP commands.
https://datatracker.ietf.org/doc/html/rfc4314
RFC 4871
DomainKeys Identified Mail (DKIM) Signatures https://datatracker.ietf.org/doc/html/rfc4871
RFC 5228
Sieve: An Email Filtering Language https://datatracker.ietf.org/doc/html/rfc5228
RFC 5321
Simple Mail Transfer Protocol https://datatracker.ietf.org/doc/html/rfc5321
RFC 5322
Internet Message Format https://datatracker.ietf.org/doc/html/rfc5322
RFC 5424
The Syslog Protocol. Used to convey event notification messages. https://datatracker.ietf.org/doc/html/rfc5424
RFC 5788
IMAP4 Keyword Registry https://datatracker.ietf.org/doc/html/rfc5788
RFC 5804
A Protocol for Remotely Managing Sieve Scripts https://datatracker.ietf.org/doc/html/rfc5804
RFC 7162
IMAP Extensions: Quick Flag Changes Resynchronization (CONDSTORE) and Quick Mailbox Resynchronization (QRESYNC) https://datatracker.ietf.org/doc/html/rfc7162
RFC9051
Internet Message Access Protocol (IMAP) - Version 4rev2 https://datatracker.ietf.org/doc/html/rfc9051