Team channels and direct messages, with organization-level communication channel and template configuration for consistent outbound comms.
Public, private, and project channels are all real records; a Direct channel between two people is found or created automatically the first time they message each other -- never duplicated.
Text and file-attachment messages are both supported, with threaded replies via parentMessageId.
Read receipts and typing indicators are real, per-channel signals, not a cosmetic placeholder.
Enterprise deployment, workflow design, and data migration — talk to the team that builds it.