What Components Make Up the Salesforce Email Message API Ecosystem

As documented in the Salesforce Email Base Class Reference, key components include: Messaging Namespace provides Apex classes for outbound email, including SingleEmailMessage and MassEmailMessage. EmailMessage sObject is the standard object storing email records associated with Cases and other records, as documented in the EmailMessage Object Reference. REST API provides endpoints for email operations, including send, query, and management. Email Services handles inbound email processing for automated record creation and updates. SOAP API offers legacy email endpoints for enterprise integrations via the sendEmail() SOAP method.

How the SingleEmailMessage API Enables Flexible Individual Email Sending

The primary API for individual email sends offers: Flexible Content to specifya custom HTML body, plain text body, or use email templates. Recipients can be email addresses directly or Contact/Lead/User IDs. Attachments are supported via the EmailFileAttachment class. Activity Logging optionally saves email as Activity on related records. Merge Fields enable template merge with targetObjectId and whatId parameters.

SingleEmailMessage Code Example for Sending a Custom Email

Messaging.SingleEmailMessage email = new Messaging.SingleEmailMessage();

email.setToAddresses(new String[] {'recipient@example.com'});
email.setSubject('Important Update');

email.setHtmlBody("<h1>Hello</h1><p>Your update is ready.</p>");
email.setPlainTextBody('Hello - Your update is ready.');

email.setSaveAsActivity(true);

Messaging.SendEmailResult[] results =
    Messaging.sendEmail(
        new Messaging.SingleEmailMessage[] { email }
    );

How the MassEmailMessage API Handles Bulk Email Sends to Record Collections

For bulk mass email sends: Template Required —must use email template with no custom body content. Recipient Lists —send to arrays of Contact, Lead, or User IDs. Higher Throughput —250 recipients per call vs. 100 for SingleEmailMessage. Related Records —setWhatIds() for merge field context from related objects. No Attachments —MassEmailMessage doesn’t support file attachments.

What the EmailMessage sObject Stores and How It Tracks Email Records

The EmailMessage object stores email records with: Case Association —emails linked to Cases via the ParentId field. Email Fields —FromAddress, ToAddress, CcAddress, BccAddress, Subject, TextBody, HtmlBody. Status Tracking —the Status field indicates Draft, Sent, Received, etc. Attachments —related ContentDocumentLink or Attachment records. Threading —ThreadIdentifier for email conversation grouping.

Which REST API Endpoints Support Email Operations in Salesforce

Key REST endpoints for email operations as documented in the Simple Email Actions Reference: Send Email: POST /services/data/vXX.0/actions/standard/emailSimple. Query EmailMessage: GET /services/data/vXX.0/query?q=SELECT...FROM EmailMessage. Create EmailMessage: POST /services/data/vXX.0/sobjects/EmailMessage. Update EmailMessage: PATCH /services/data/vXX.0/sobjects/EmailMessage/{id}.

What Sending Limits the Email Message API Imposes on Operations

Key Salesforce email limits apply: Daily Single Email: 5,000 emails per day organization-wide via SingleEmailMessage. Daily Mass Email: 5,000 external recipients per day via MassEmailMessage. Per-Transaction: 10 sendEmail() invocations per Apex transaction. Recipients Per Call: 100 for SingleEmailMessage, 250 for MassEmailMessage. API Call Limits: REST/SOAP calls count against daily API limits.

How Email Services Process Inbound Emails for Automated Record Creation

Process inbound emails programmatically: InboundEmail Class represents incoming email with headers, body, and attachments. InboundEmailHandler is the interface to implement for custom email processing logic. Email Address is a unique Salesforce-generated address for the service. Use Cases include creating Leads, updating Cases, and logging Activities from inbound emails.

Inbound Email Handler Code Example for Creating Leads from Email

global class MyEmailHandler implements Messaging.InboundEmailHandler {

    global Messaging.InboundEmailResult handleInboundEmail(
        Messaging.InboundEmail email,
        Messaging.InboundEnvelope envelope
    ) {

        Messaging.InboundEmailResult result =
            new Messaging.InboundEmailResult();

        // Process email
        String subject = email.subject;
        String body = email.plainTextBody;
        String fromAddress = email.fromAddress;

        // Create Lead from email
        Lead newLead = new Lead(
            Email = fromAddress,
            LastName = email.fromName,
            Description = body
        );

        insert newLead;

        result.success = true;
        return result;
    }
}

How to Properly Handle Email Message API Responses and Errors

Always check SendEmailResult for failures:

Messaging.SendEmailResult[] results = Messaging.sendEmail(emails);

for (Messaging.SendEmailResult result : results) {

    if (!result.isSuccess()) {

        List errors =
            result.getErrors();

        for (Messaging.SendEmailError error : errors) {

            System.debug('Status Code: ' + error.getStatusCode());
            System.debug('Message: ' + error.getMessage());
            System.debug('Fields: ' + error.getFields());

        }
    }
}

Email Message API Best Practices for Reliable Programmatic Sending

Bulkify Sends: Batch emails in arrays to minimize sendEmail() calls. Check Limits: Use Limits.getEmailInvocations() before sending. Handle Errors: Always check SendEmailResult for failures. Respect Opt-Out: Honor opt-out and unsubscribe preferences. Log Activity: Enable saveAsActivity for email tracking. Test Thoroughly: Use Test.isRunningTest() to handle email in test context.

What Limitations Constrain Native Email Message API at Scale

Daily Limits: 5,000/day ceiling constrains email campaigns. No Native Tracking: The API doesn’t provide open rates or click tracking. Shared IPs: Email deliverability depends on Salesforce’s shared infrastructure. Template Constraints: MassEmailMessage requires templates—no dynamic body. Scheduling: No built-in scheduling—requires custom Scheduled Apex.

How Email Message API Integrates with Marketing Workflows and Automation

Campaign Tracking: Link emails to email campaigns for attribution. Automation: Build email automation with triggered emails via Apex triggers. Sequences: Implement email sequences and drip campaigns with scheduled Apex. Follow-Ups: Create follow-up sequences based on engagement.

Enhanced Email Capabilities That Scale Beyond Native API Limits

For organizations needing enhanced email beyond API limits, MassMailer operates 100% native to Salesforce. Unlimited sending without governor constraints. Complete email capabilities with email analytics and email metrics. Use the email builder for contact list targeting.

Key Takeaways

• Email Message API includes Messaging classes, EmailMessage sObject, and REST endpoints
• SingleEmailMessage offers flexibility; MassEmailMessage enables higher throughput with templates
• Email Services processes inbound emails for automation
• Native solutions extend capabilities beyond API limitations

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