Outlook and MAPI Resources

Official Documentation

MAPI Programming Overview Start here for Microsoft's Extended MAPI concepts and terminology.
Outlook MAPI Reference Interfaces, functions, constants, property tags, structures, and MAPI samples.
Outlook Object Model Reference Outlook object model reference and programming topics for automation and add-ins.

Developer Q&A

Stack Overflow: MAPI Current MAPI questions, answers, and implementation discussions.
Stack Overflow: Outlook Outlook Object Model, add-in, automation, and integration questions.
MAPI-L Archive Searchable archive of the long-running Extended MAPI developer mailing list.

Outlook Community

Slipstick Outlook and Exchange tips, troubleshooting articles, utilities, and add-in references.
Robert365 Outlook, Microsoft 365, and Exchange resources from Outlook MVP Robert Sparnaaij.

Downloads

Extended MAPI Headers for Delphi Delphi translations of Extended MAPI headers for native Outlook development.
TNEF Stream Reader Delphi Class Delphi class for reading and extracting properties from a TNEF stream, including winmail.dat files.