diff --git a/src/services/billingRequestTemplateService.ts b/src/services/billingRequestTemplateService.ts
index 3df12949..dd392139 100644
--- a/src/services/billingRequestTemplateService.ts
+++ b/src/services/billingRequestTemplateService.ts
@@ -66,7 +66,7 @@ interface BillingRequestTemplateCreateRequest {
 
   // Verification preference for the mandate.
 
-  mandate_request_verify?: string;
+  mandate_request_verify?: `${Types.BillingRequestTemplateMandateRequestVerify}`;
 
   // Key-value store of custom data. Up to 3 keys are permitted, with key names up
   // to 50 characters and values up to 500 characters.
@@ -143,7 +143,7 @@ interface BillingRequestTemplateUpdateRequest {
 
   // Verification preference for the mandate.
 
-  mandate_request_verify?: string;
+  mandate_request_verify?: `${Types.BillingRequestTemplateMandateRequestVerify}`;
 
   // Key-value store of custom data. Up to 3 keys are permitted, with key names up
   // to 50 characters and values up to 500 characters.
diff --git a/src/types/Types.ts b/src/types/Types.ts
index 874bb5de..4b231292 100644
--- a/src/types/Types.ts
+++ b/src/types/Types.ts
@@ -1631,7 +1631,7 @@ export type BillingRequestTemplate = {
   mandate_request_scheme?: string | null;
 
   // Verification preference for the mandate.
-  mandate_request_verify?: string | null;
+  mandate_request_verify?: `${BillingRequestTemplateMandateRequestVerify}` | null;
 
   // Key-value store of custom data. Up to 3 keys are permitted, with key names
   // up to 50 characters and values up to 500 characters.
@@ -1683,6 +1683,13 @@ export type BillingRequestTemplateCreateRequestLinks = {
   creditor?: string;
 };
 
+export enum BillingRequestTemplateMandateRequestVerify {
+  Minimum = 'minimum',
+  Recommended = 'recommended',
+  WhenAvailable = 'when_available',
+  Always = 'always',
+}
+
 /** Type for a billingrequesttemplatemandaterequestconstraints resource. */
 export type BillingRequestTemplateMandateRequestConstraints = {
   // The latest date at which payments can be taken, must occur after start_date