diff --git a/packages/lib/jobs/definitions/emails/send-signing-email.handler.ts b/packages/lib/jobs/definitions/emails/send-signing-email.handler.ts
index 9c057cc16..a3156b7d5 100644
--- a/packages/lib/jobs/definitions/emails/send-signing-email.handler.ts
+++ b/packages/lib/jobs/definitions/emails/send-signing-email.handler.ts
@@ -16,6 +16,7 @@ import { createElement } from 'react';
 import { getI18nInstance } from '../../../client-only/providers/i18n-server';
 import { NEXT_PUBLIC_WEBAPP_URL } from '../../../constants/app';
 import { RECIPIENT_ROLE_TO_EMAIL_TYPE, RECIPIENT_ROLES_DESCRIPTION } from '../../../constants/recipient-roles';
+import { buildEnvelopeEmailHeaders } from '../../../server-only/email/build-envelope-email-headers';
 import { getEmailContext } from '../../../server-only/email/get-email-context';
 import { assertOrganisationRatesAndLimits } from '../../../server-only/rate-limit/assert-organisation-rates-and-limits';
 import { updateRecipientNextReminder } from '../../../server-only/recipient/update-recipient-next-reminder';
@@ -224,6 +225,11 @@ export const run = async ({ payload, io }: { payload: TSendSigningEmailJobDefini
         subject: renderCustomEmailTemplate(documentMeta?.subject || emailSubject, customEmailTemplate),
         html,
         text,
+        headers: buildEnvelopeEmailHeaders({
+          userId,
+          envelopeId: envelope.id,
+          teamId: envelope.teamId,
+        }),
       });
     });
   }
diff --git a/packages/lib/jobs/definitions/internal/process-signing-reminder.handler.ts b/packages/lib/jobs/definitions/internal/process-signing-reminder.handler.ts
index 5f9ef9e11..b755de015 100644
--- a/packages/lib/jobs/definitions/internal/process-signing-reminder.handler.ts
+++ b/packages/lib/jobs/definitions/internal/process-signing-reminder.handler.ts
@@ -16,6 +16,7 @@ import { createElement } from 'react';
 import { getI18nInstance } from '../../../client-only/providers/i18n-server';
 import { NEXT_PUBLIC_WEBAPP_URL } from '../../../constants/app';
 import { RECIPIENT_ROLES_DESCRIPTION } from '../../../constants/recipient-roles';
+import { buildEnvelopeEmailHeaders } from '../../../server-only/email/build-envelope-email-headers';
 import { getEmailContext } from '../../../server-only/email/get-email-context';
 import { assertOrganisationRatesAndLimits } from '../../../server-only/rate-limit/assert-organisation-rates-and-limits';
 import { updateRecipientNextReminder } from '../../../server-only/recipient/update-recipient-next-reminder';
@@ -211,6 +212,11 @@ export const run = async ({ payload, io }: { payload: TProcessSigningReminderJob
       subject: emailSubject,
       html,
       text,
+      headers: buildEnvelopeEmailHeaders({
+        userId: envelope.userId,
+        envelopeId: envelope.id,
+        teamId: envelope.teamId,
+      }),
     });
 
     await prisma.documentAuditLog.create({
diff --git a/packages/lib/server-only/document/resend-document.ts b/packages/lib/server-only/document/resend-document.ts
index 21f4034d6..e0f119bcc 100644
--- a/packages/lib/server-only/document/resend-document.ts
+++ b/packages/lib/server-only/document/resend-document.ts
@@ -27,6 +27,7 @@ import { isDocumentCompleted } from '../../utils/document';
 import type { EnvelopeIdOptions } from '../../utils/envelope';
 import { isRecipientEmailValidForSending } from '../../utils/recipients';
 import { renderEmailWithI18N } from '../../utils/render-email-with-i18n';
+import { buildEnvelopeEmailHeaders } from '../email/build-envelope-email-headers';
 import { getEmailContext } from '../email/get-email-context';
 import { getEnvelopeWhereInput } from '../envelope/get-envelope-by-id';
 import { assertOrganisationRatesAndLimits } from '../rate-limit/assert-organisation-rates-and-limits';
@@ -255,6 +256,11 @@ export const resendDocument = async ({ id, userId, recipients, teamId, requestMe
           : emailSubject,
         html,
         text,
+        headers: buildEnvelopeEmailHeaders({
+          userId: envelope.userId,
+          envelopeId: envelope.id,
+          teamId: envelope.teamId,
+        }),
       });
 
       await prisma.documentAuditLog.create({
diff --git a/packages/lib/server-only/email/build-envelope-email-headers.ts b/packages/lib/server-only/email/build-envelope-email-headers.ts
new file mode 100644
index 000000000..c6a0e102c
--- /dev/null
+++ b/packages/lib/server-only/email/build-envelope-email-headers.ts
@@ -0,0 +1,26 @@
+export type BuildEnvelopeEmailHeadersOptions = {
+  userId: number;
+  envelopeId: string;
+  teamId: number;
+};
+
+/**
+ * Builds opaque sender-attribution headers stamped onto outgoing user-triggered
+ * envelope emails. These appear in AWS SES bounce/complaint notifications (when
+ * "include original headers" is enabled) so an abusive send can be traced back
+ * to the originating Documenso user via the admin panel.
+ *
+ * Only opaque IDs are included so recipients cannot see the sender's email
+ * address or name in the delivered message source.
+ */
+export const buildEnvelopeEmailHeaders = ({
+  userId,
+  envelopeId,
+  teamId,
+}: BuildEnvelopeEmailHeadersOptions): Record<string, string> => {
+  return {
+    'X-Documenso-Sender-User-Id': String(userId),
+    'X-Documenso-Envelope-Id': envelopeId,
+    'X-Documenso-Team-Id': String(teamId),
+  };
+};