Email Message
An Email Message in Salesforce is a standard object (EmailMessage in the API) that stores the full content and metadata of a single email sent or received within the platform.
Definition
An Email Message in Salesforce is a standard object (EmailMessage in the API) that stores the full content and metadata of a single email sent or received within the platform. It captures the subject, plain-text body, HTML body, from and to addresses, CC and BCC recipients, message date, raw headers, attachments, and a status flag indicating whether the message is New, Read, Replied, Sent, Forwarded, or Draft. Email Messages are most commonly created automatically by Email-to-Case (which converts inbound emails into Cases and stores each message as a child record), the Send Email quick action on Cases or other records, and connected mail systems like Salesforce Inbox, Einstein Activity Capture, or third-party email integrations. Each Email Message has a ParentId that links it to a Case, Lead, Contact, Account, or custom object — making it the primary record type for the email conversation history visible in the Lightning Service Console.
In plain English
“An Email Message is one email — sent or received — stored as a record in Salesforce. When a customer emails support@yourcompany.com, that email becomes an Email Message attached to a Case. When an agent replies, that reply is also an Email Message. Together they form the conversation thread the agent sees on the Case page.”
Worked example
A customer emails support@acme.com asking why their invoice was charged twice. Salesforce's Email-to-Case service receives the message, creates a new Case, and stores the email as an Email Message child record with Status = "New" and IsIncoming = true. A support agent opens the Case, reads the email message, clicks Reply in the email composer, and sends an explanation. That reply is saved as a second Email Message on the same Case with Status = "Sent" and IsIncoming = false. The customer responds — a third Email Message lands on the Case. The agent now has the entire thread — three Email Message records — visible in chronological order in the Case Feed, with full headers preserved for compliance and traceability.
Why Email Message matters
Email Messages live under their parent record through ParentId, but they also relate to multiple people through the EmailMessageRelation junction object. EmailMessageRelation rows record which Contacts, Leads, or Users were on the To, CC, or BCC line of each message. This separation matters because a single email can have many recipients of different types, and reporting on email touchpoints per Contact requires joining through EmailMessageRelation rather than just looking at raw address strings.
Storage and retention can become a significant cost in Service Cloud orgs that handle high email volume. Each inbound email — including raw MIME headers and any attachments — counts against File Storage. Email-to-Case threading also has well-known edge cases: missing or rewritten message-id headers, mail clients that reformat reply chains, and forwarded conversations can all cause new emails to land as separate Cases instead of threading into existing ones. Threading Token configuration (the GUID Salesforce embeds in outgoing emails) is the most reliable mechanism.
The EmailMessage object exposes a Headers field containing the raw RFC 2822 headers, which is invaluable for debugging delivery issues but is also subject to truncation for very large headers. RelatedToId (separate from ParentId) lets a message reference any other related record, useful when an email about an Opportunity is filed under a Case but should also surface on the Opportunity timeline. Custom fields on EmailMessage are supported and frequently used for sentiment analysis, priority tagging, or first-response-time tracking metadata.
How organizations use Email Message
Routes all inbound support email through Email-to-Case, creating one Case per conversation thread and one Email Message per actual email. Reporting on first-response time uses the timestamp gap between the inbound Email Message and the first outbound reply — a primary KPI for the support org.
Captures sales rep email conversations through Einstein Activity Capture, which writes Email Message records linked to the relevant Contact and Opportunity. Pipeline reviews surface the most recent Email Message on each open Opportunity so leadership can see what was just discussed without asking the rep.
Retains every Email Message indefinitely with a custom retention flag that prevents deletion, satisfying SEC recordkeeping rules. The Headers field is preserved for audit purposes, and all customer-facing emails are routed through Salesforce so the entire compliance archive lives in one queryable place.
Trust & references
Straight from the source — Salesforce's reference material on Email Message.
- EmailMessage in Object Reference for the Salesforce PlatformSalesforce Developer Documentation
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