diff --git a/src/backend/clients/prelude/PreludeClient.test.ts b/src/backend/clients/prelude/PreludeClient.test.ts
index 2c016de40..f03d6d424 100644
--- a/src/backend/clients/prelude/PreludeClient.test.ts
+++ b/src/backend/clients/prelude/PreludeClient.test.ts
@@ -79,8 +79,9 @@ describe('PreludeClient', () => {
         expect(init.headers.Authorization).toBe('Bearer sk_test');
         expect(JSON.parse(init.body)).toEqual({
             target: { type: 'phone_number', value: '+14155550123' },
-            // Defaults to RCS (cheaper); Prelude falls back to SMS.
-            options: { code_size: 6, preferred_channel: 'rcs' },
+            // Defaults to RCS (cheaper); Prelude falls back to SMS. locale is
+            // hardcoded to en-US so the message text is always English.
+            options: { code_size: 6, preferred_channel: 'rcs', locale: 'en-US' },
             signals: { ip: '203.0.113.7' },
         });
     });
@@ -131,6 +132,7 @@ describe('PreludeClient', () => {
         expect(JSON.parse(init.body).options).toEqual({
             code_size: 6,
             preferred_channel: 'sms', // config override beats the rcs default
+            locale: 'en-US',
             template_id: 'tmpl_puter',
             sender_id: 'Puter',
         });
diff --git a/src/backend/clients/prelude/PreludeClient.ts b/src/backend/clients/prelude/PreludeClient.ts
index dd0f21d16..716f06313 100644
--- a/src/backend/clients/prelude/PreludeClient.ts
+++ b/src/backend/clients/prelude/PreludeClient.ts
@@ -144,6 +144,7 @@ export class PreludeClient extends PuterClient {
             preferred_channel:
                 this.config.prelude?.preferredChannel ??
                 DEFAULT_PREFERRED_CHANNEL,
+            locale: 'en-US',
         };
         // Branding lives in the Prelude dashboard (the message text is a
         // template); these just select a Puter-branded template / sender when