Chat GUID format
Chat GUIDs identify an iMessage conversation. They follow a three-part semicolon-separated format:Direct conversation GUIDs
For one-on-one conversations, the address is the phone number or Apple ID email of the other participant.Always include the country code in phone numbers. For US numbers, the country
code is
+1, so a number like (555) 000-1234 becomes +15550001234.Group chat GUIDs
Group chats use a server-generated random identifier in the address segment rather than a participant’s contact info. You cannot construct a group chat GUID yourself — you discover it by querying the chats list.Message GUIDs
Individual messages within a chat each carry their own GUID. Message GUIDs are opaque strings assigned by the iMessage infrastructure and returned to you in API responses. You use them when reacting to a message, replying to it, or fetching a specific message.Attachment GUIDs
Attachments — images, videos, audio messages, and files — each have a GUID returned when you query a message that contains one. Use the attachment GUID to fetch metadata or download the file.Handle addresses
Handles represent individual participants — effectively a contact address used as an iMessage endpoint. The handle address is the raw phone number or email, without theiMessage;+; prefix that wraps a chat GUID.
How GUIDs appear in SDK calls
Most SDK methods that target a specific chat accept achatGuid parameter. Pass the full iMessage;+;... or iMessage;-;... string.
tempGuid — a client-generated identifier you create (typically a UUID v4) used to deduplicate the message on the server side. This prevents the same message from being delivered twice if your request is retried.