diff --git a/.changeset/types-0-34.md b/.changeset/types-0-34.md
new file mode 100644
index 0000000..94ec8cc
--- /dev/null
+++ b/.changeset/types-0-34.md
@@ -0,0 +1,5 @@
+---
+"@seamless-auth/messaging": patch
+---
+
+Depend on `@seamless-auth/types` ^0.34.0, the version the auth API and server adapters use, so an install no longer carries two copies. Types 0.34.0 adds the optional `headers` field to `EmailMessage`, so `EmailMessage` is now the shared type itself rather than a local extension of it. Its shape is unchanged.
diff --git a/package-lock.json b/package-lock.json
index 4777c11..ce04837 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1290,9 +1290,9 @@
       "link": true
     },
     "node_modules/@seamless-auth/types": {
-      "version": "0.33.0",
-      "resolved": "https://registry.npmjs.org/@seamless-auth/types/-/types-0.33.0.tgz",
-      "integrity": "sha512-zg0vp+4BGH8gEktYrpU040mAuB/Ebz0orLxqNf3iOavYPzqj3ST9i12IwUKGkbu4A1455JAexrTSZH6C7400jQ==",
+      "version": "0.34.0",
+      "resolved": "https://registry.npmjs.org/@seamless-auth/types/-/types-0.34.0.tgz",
+      "integrity": "sha512-bTgZkEdpXwAejxwnA1J8vTGAq+FW9L6J4n97q2MI6SqWWIOqXyaF6zMTkzeKqNTvfgF0NIn2DHh9qXL+92FN/A==",
       "license": "Apache-2.0",
       "dependencies": {
         "zod": "^4.5.0"
@@ -4266,7 +4266,7 @@
       "version": "0.3.0",
       "license": "Apache-2.0",
       "dependencies": {
-        "@seamless-auth/types": "^0.33.0"
+        "@seamless-auth/types": "^0.34.0"
       },
       "engines": {
         "node": ">=18"
diff --git a/packages/core/package.json b/packages/core/package.json
index ac4e0e7..fa6b1dc 100644
--- a/packages/core/package.json
+++ b/packages/core/package.json
@@ -34,6 +34,6 @@
     "access": "public"
   },
   "dependencies": {
-    "@seamless-auth/types": "^0.33.0"
+    "@seamless-auth/types": "^0.34.0"
   }
 }
diff --git a/packages/core/src/types.ts b/packages/core/src/types.ts
index 4180a57..1231a41 100644
--- a/packages/core/src/types.ts
+++ b/packages/core/src/types.ts
@@ -1,12 +1,6 @@
-import type { EmailMessage as SharedEmailMessage } from "@seamless-auth/types";
-
-export type { DeliveryResult, MessagingChannel, SmsMessage } from "@seamless-auth/types";
-
-export type EmailMessage = SharedEmailMessage & {
-  /**
-   * Extra headers to send with the message, such as `List-Unsubscribe`. Names
-   * and values are passed through as given; a transport that cannot send
-   * custom headers ignores them.
-   */
-  headers?: Record<string, string>;
-};
+export type {
+  DeliveryResult,
+  EmailMessage,
+  MessagingChannel,
+  SmsMessage,
+} from "@seamless-auth/types";