diff --git a/codegen/internal/generator/templates/client.tmpl b/codegen/internal/generator/templates/client.tmpl
index eff243a..bfbe438 100644
--- a/codegen/internal/generator/templates/client.tmpl
+++ b/codegen/internal/generator/templates/client.tmpl
@@ -162,7 +162,7 @@ public final class {{ .ClassName }} {
 {{- end }}
         String path = {{ quote .Path }};
 {{- range .PathParams }}
-        path = path.replace({{ quote (printf "{%s}" .Name) }}, ApiClient.urlEncode(String.valueOf({{ .FieldName }})));
+        path = path.replace({{ quote (printf "{%s}" .Name) }}, ApiClient.urlEncode(ApiClient.parameterValue({{ .FieldName }})));
 {{- end }}
 
 {{- if or .RequiredQueryParams .OptionalQueryParams }}
diff --git a/codegen/internal/generator/templates/client_async.tmpl b/codegen/internal/generator/templates/client_async.tmpl
index b31c95e..335d1b8 100644
--- a/codegen/internal/generator/templates/client_async.tmpl
+++ b/codegen/internal/generator/templates/client_async.tmpl
@@ -164,7 +164,7 @@ public final class {{ .ClassName }} {
 {{- end }}
         String path = {{ quote .Path }};
 {{- range .PathParams }}
-        path = path.replace({{ quote (printf "{%s}" .Name) }}, ApiClient.urlEncode(String.valueOf({{ .FieldName }})));
+        path = path.replace({{ quote (printf "{%s}" .Name) }}, ApiClient.urlEncode(ApiClient.parameterValue({{ .FieldName }})));
 {{- end }}
 
 {{- if or .RequiredQueryParams .OptionalQueryParams }}
diff --git a/src/main/java/com/sumup/sdk/clients/CheckoutsAsyncClient.java b/src/main/java/com/sumup/sdk/clients/CheckoutsAsyncClient.java
index 899fe32..1938ce2 100644
--- a/src/main/java/com/sumup/sdk/clients/CheckoutsAsyncClient.java
+++ b/src/main/java/com/sumup/sdk/clients/CheckoutsAsyncClient.java
@@ -88,7 +88,7 @@ public CompletableFuture<java.util.Map<String, Object>> createApplePaySession(
       throws ApiException {
     Objects.requireNonNull(id, "id");
     String path = "/v0.2/checkouts/{id}/apple-pay-session";
-    path = path.replace("{id}", ApiClient.urlEncode(String.valueOf(id)));
+    path = path.replace("{id}", ApiClient.urlEncode(ApiClient.parameterValue(id)));
 
     return this.apiClient.sendAsync(
         HttpMethod.PUT,
@@ -190,7 +190,7 @@ public CompletableFuture<com.sumup.sdk.models.Checkout> deactivateCheckout(
       String id, RequestOptions requestOptions) throws ApiException {
     Objects.requireNonNull(id, "id");
     String path = "/v0.1/checkouts/{id}";
-    path = path.replace("{id}", ApiClient.urlEncode(String.valueOf(id)));
+    path = path.replace("{id}", ApiClient.urlEncode(ApiClient.parameterValue(id)));
 
     return this.apiClient.sendAsync(
         HttpMethod.DELETE,
@@ -239,7 +239,7 @@ public CompletableFuture<com.sumup.sdk.models.CheckoutSuccess> getCheckout(
       String id, RequestOptions requestOptions) throws ApiException {
     Objects.requireNonNull(id, "id");
     String path = "/v0.1/checkouts/{id}";
-    path = path.replace("{id}", ApiClient.urlEncode(String.valueOf(id)));
+    path = path.replace("{id}", ApiClient.urlEncode(ApiClient.parameterValue(id)));
 
     return this.apiClient.sendAsync(
         HttpMethod.GET,
@@ -312,7 +312,9 @@ public CompletableFuture<com.sumup.sdk.models.GetPaymentMethodsResponse> getPaym
       throws ApiException {
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v0.1/merchants/{merchant_code}/payment-methods";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
     Map<String, Object> queryParams = new LinkedHashMap<>();
     if (getPaymentMethods != null) {
       queryParams.putAll(getPaymentMethods.toMap());
@@ -441,7 +443,7 @@ public CompletableFuture<com.sumup.sdk.models.CheckoutSuccess> processCheckout(
     Objects.requireNonNull(id, "id");
     Objects.requireNonNull(request, "request");
     String path = "/v0.1/checkouts/{id}";
-    path = path.replace("{id}", ApiClient.urlEncode(String.valueOf(id)));
+    path = path.replace("{id}", ApiClient.urlEncode(ApiClient.parameterValue(id)));
 
     return this.apiClient.sendAsync(
         HttpMethod.PUT,
diff --git a/src/main/java/com/sumup/sdk/clients/CheckoutsClient.java b/src/main/java/com/sumup/sdk/clients/CheckoutsClient.java
index 8710e82..3a703bc 100644
--- a/src/main/java/com/sumup/sdk/clients/CheckoutsClient.java
+++ b/src/main/java/com/sumup/sdk/clients/CheckoutsClient.java
@@ -87,7 +87,7 @@ public java.util.Map<String, Object> createApplePaySession(
       throws ApiException {
     Objects.requireNonNull(id, "id");
     String path = "/v0.2/checkouts/{id}/apple-pay-session";
-    path = path.replace("{id}", ApiClient.urlEncode(String.valueOf(id)));
+    path = path.replace("{id}", ApiClient.urlEncode(ApiClient.parameterValue(id)));
 
     return this.apiClient.send(
         HttpMethod.PUT,
@@ -188,7 +188,7 @@ public com.sumup.sdk.models.Checkout deactivateCheckout(String id, RequestOption
       throws ApiException {
     Objects.requireNonNull(id, "id");
     String path = "/v0.1/checkouts/{id}";
-    path = path.replace("{id}", ApiClient.urlEncode(String.valueOf(id)));
+    path = path.replace("{id}", ApiClient.urlEncode(ApiClient.parameterValue(id)));
 
     return this.apiClient.send(
         HttpMethod.DELETE,
@@ -236,7 +236,7 @@ public com.sumup.sdk.models.CheckoutSuccess getCheckout(String id, RequestOption
       throws ApiException {
     Objects.requireNonNull(id, "id");
     String path = "/v0.1/checkouts/{id}";
-    path = path.replace("{id}", ApiClient.urlEncode(String.valueOf(id)));
+    path = path.replace("{id}", ApiClient.urlEncode(ApiClient.parameterValue(id)));
 
     return this.apiClient.send(
         HttpMethod.GET,
@@ -306,7 +306,9 @@ public com.sumup.sdk.models.GetPaymentMethodsResponse getPaymentMethods(
       throws ApiException {
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v0.1/merchants/{merchant_code}/payment-methods";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
     Map<String, Object> queryParams = new LinkedHashMap<>();
     if (getPaymentMethods != null) {
       queryParams.putAll(getPaymentMethods.toMap());
@@ -431,7 +433,7 @@ public com.sumup.sdk.models.CheckoutSuccess processCheckout(
     Objects.requireNonNull(id, "id");
     Objects.requireNonNull(request, "request");
     String path = "/v0.1/checkouts/{id}";
-    path = path.replace("{id}", ApiClient.urlEncode(String.valueOf(id)));
+    path = path.replace("{id}", ApiClient.urlEncode(ApiClient.parameterValue(id)));
 
     return this.apiClient.send(
         HttpMethod.PUT,
diff --git a/src/main/java/com/sumup/sdk/clients/CustomersAsyncClient.java b/src/main/java/com/sumup/sdk/clients/CustomersAsyncClient.java
index 755693b..95bb02e 100644
--- a/src/main/java/com/sumup/sdk/clients/CustomersAsyncClient.java
+++ b/src/main/java/com/sumup/sdk/clients/CustomersAsyncClient.java
@@ -115,8 +115,8 @@ public CompletableFuture<Void> deactivatePaymentInstrument(
     Objects.requireNonNull(customerId, "customerId");
     Objects.requireNonNull(token, "token");
     String path = "/v0.1/customers/{customer_id}/payment-instruments/{token}";
-    path = path.replace("{customer_id}", ApiClient.urlEncode(String.valueOf(customerId)));
-    path = path.replace("{token}", ApiClient.urlEncode(String.valueOf(token)));
+    path = path.replace("{customer_id}", ApiClient.urlEncode(ApiClient.parameterValue(customerId)));
+    path = path.replace("{token}", ApiClient.urlEncode(ApiClient.parameterValue(token)));
 
     return this.apiClient.sendAsync(
         HttpMethod.DELETE, path, null, null, null, null, requestOptions);
@@ -159,7 +159,7 @@ public CompletableFuture<com.sumup.sdk.models.Customer> getCustomer(
       String customerId, RequestOptions requestOptions) throws ApiException {
     Objects.requireNonNull(customerId, "customerId");
     String path = "/v0.1/customers/{customer_id}";
-    path = path.replace("{customer_id}", ApiClient.urlEncode(String.valueOf(customerId)));
+    path = path.replace("{customer_id}", ApiClient.urlEncode(ApiClient.parameterValue(customerId)));
 
     return this.apiClient.sendAsync(
         HttpMethod.GET,
@@ -208,7 +208,7 @@ public CompletableFuture<com.sumup.sdk.models.Customer> getCustomer(
       listPaymentInstruments(String customerId, RequestOptions requestOptions) throws ApiException {
     Objects.requireNonNull(customerId, "customerId");
     String path = "/v0.1/customers/{customer_id}/payment-instruments";
-    path = path.replace("{customer_id}", ApiClient.urlEncode(String.valueOf(customerId)));
+    path = path.replace("{customer_id}", ApiClient.urlEncode(ApiClient.parameterValue(customerId)));
 
     return this.apiClient.sendAsync(
         HttpMethod.GET,
@@ -265,7 +265,7 @@ public CompletableFuture<com.sumup.sdk.models.Customer> updateCustomer(
     Objects.requireNonNull(customerId, "customerId");
     Objects.requireNonNull(request, "request");
     String path = "/v0.1/customers/{customer_id}";
-    path = path.replace("{customer_id}", ApiClient.urlEncode(String.valueOf(customerId)));
+    path = path.replace("{customer_id}", ApiClient.urlEncode(ApiClient.parameterValue(customerId)));
 
     return this.apiClient.sendAsync(
         HttpMethod.PUT,
diff --git a/src/main/java/com/sumup/sdk/clients/CustomersClient.java b/src/main/java/com/sumup/sdk/clients/CustomersClient.java
index f7fccc5..477c993 100644
--- a/src/main/java/com/sumup/sdk/clients/CustomersClient.java
+++ b/src/main/java/com/sumup/sdk/clients/CustomersClient.java
@@ -111,8 +111,8 @@ public void deactivatePaymentInstrument(
     Objects.requireNonNull(customerId, "customerId");
     Objects.requireNonNull(token, "token");
     String path = "/v0.1/customers/{customer_id}/payment-instruments/{token}";
-    path = path.replace("{customer_id}", ApiClient.urlEncode(String.valueOf(customerId)));
-    path = path.replace("{token}", ApiClient.urlEncode(String.valueOf(token)));
+    path = path.replace("{customer_id}", ApiClient.urlEncode(ApiClient.parameterValue(customerId)));
+    path = path.replace("{token}", ApiClient.urlEncode(ApiClient.parameterValue(token)));
 
     this.apiClient.send(HttpMethod.DELETE, path, null, null, null, null, requestOptions);
   }
@@ -153,7 +153,7 @@ public com.sumup.sdk.models.Customer getCustomer(String customerId, RequestOptio
       throws ApiException {
     Objects.requireNonNull(customerId, "customerId");
     String path = "/v0.1/customers/{customer_id}";
-    path = path.replace("{customer_id}", ApiClient.urlEncode(String.valueOf(customerId)));
+    path = path.replace("{customer_id}", ApiClient.urlEncode(ApiClient.parameterValue(customerId)));
 
     return this.apiClient.send(
         HttpMethod.GET,
@@ -200,7 +200,7 @@ public java.util.List<com.sumup.sdk.models.PaymentInstrumentResponse> listPaymen
       String customerId, RequestOptions requestOptions) throws ApiException {
     Objects.requireNonNull(customerId, "customerId");
     String path = "/v0.1/customers/{customer_id}/payment-instruments";
-    path = path.replace("{customer_id}", ApiClient.urlEncode(String.valueOf(customerId)));
+    path = path.replace("{customer_id}", ApiClient.urlEncode(ApiClient.parameterValue(customerId)));
 
     return this.apiClient.send(
         HttpMethod.GET,
@@ -257,7 +257,7 @@ public com.sumup.sdk.models.Customer updateCustomer(
     Objects.requireNonNull(customerId, "customerId");
     Objects.requireNonNull(request, "request");
     String path = "/v0.1/customers/{customer_id}";
-    path = path.replace("{customer_id}", ApiClient.urlEncode(String.valueOf(customerId)));
+    path = path.replace("{customer_id}", ApiClient.urlEncode(ApiClient.parameterValue(customerId)));
 
     return this.apiClient.send(
         HttpMethod.PUT,
diff --git a/src/main/java/com/sumup/sdk/clients/MembersAsyncClient.java b/src/main/java/com/sumup/sdk/clients/MembersAsyncClient.java
index 598d89a..1662a82 100644
--- a/src/main/java/com/sumup/sdk/clients/MembersAsyncClient.java
+++ b/src/main/java/com/sumup/sdk/clients/MembersAsyncClient.java
@@ -71,7 +71,9 @@ public CompletableFuture<com.sumup.sdk.models.Member> createMerchantMember(
     Objects.requireNonNull(merchantCode, "merchantCode");
     Objects.requireNonNull(request, "request");
     String path = "/v0.1/merchants/{merchant_code}/members";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
 
     return this.apiClient.sendAsync(
         HttpMethod.POST,
@@ -121,8 +123,10 @@ public CompletableFuture<Void> deleteMerchantMember(
     Objects.requireNonNull(memberId, "memberId");
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v0.1/merchants/{merchant_code}/members/{member_id}";
-    path = path.replace("{member_id}", ApiClient.urlEncode(String.valueOf(memberId)));
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path = path.replace("{member_id}", ApiClient.urlEncode(ApiClient.parameterValue(memberId)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
 
     return this.apiClient.sendAsync(
         HttpMethod.DELETE, path, null, null, null, null, requestOptions);
@@ -166,8 +170,10 @@ public CompletableFuture<com.sumup.sdk.models.Member> getMerchantMember(
     Objects.requireNonNull(memberId, "memberId");
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v0.1/merchants/{merchant_code}/members/{member_id}";
-    path = path.replace("{member_id}", ApiClient.urlEncode(String.valueOf(memberId)));
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path = path.replace("{member_id}", ApiClient.urlEncode(ApiClient.parameterValue(memberId)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
 
     return this.apiClient.sendAsync(
         HttpMethod.GET,
@@ -240,7 +246,9 @@ public CompletableFuture<com.sumup.sdk.models.ListMerchantMembersResponse> listM
       throws ApiException {
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v0.1/merchants/{merchant_code}/members";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
     Map<String, Object> queryParams = new LinkedHashMap<>();
     if (listMerchantMembers != null) {
       queryParams.putAll(listMerchantMembers.toMap());
@@ -304,8 +312,10 @@ public CompletableFuture<com.sumup.sdk.models.Member> updateMerchantMember(
     Objects.requireNonNull(merchantCode, "merchantCode");
     Objects.requireNonNull(request, "request");
     String path = "/v0.1/merchants/{merchant_code}/members/{member_id}";
-    path = path.replace("{member_id}", ApiClient.urlEncode(String.valueOf(memberId)));
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path = path.replace("{member_id}", ApiClient.urlEncode(ApiClient.parameterValue(memberId)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
 
     return this.apiClient.sendAsync(
         HttpMethod.PUT,
diff --git a/src/main/java/com/sumup/sdk/clients/MembersClient.java b/src/main/java/com/sumup/sdk/clients/MembersClient.java
index 63e20d1..a0c5ff6 100644
--- a/src/main/java/com/sumup/sdk/clients/MembersClient.java
+++ b/src/main/java/com/sumup/sdk/clients/MembersClient.java
@@ -70,7 +70,9 @@ public com.sumup.sdk.models.Member createMerchantMember(
     Objects.requireNonNull(merchantCode, "merchantCode");
     Objects.requireNonNull(request, "request");
     String path = "/v0.1/merchants/{merchant_code}/members";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
 
     return this.apiClient.send(
         HttpMethod.POST,
@@ -117,8 +119,10 @@ public void deleteMerchantMember(
     Objects.requireNonNull(memberId, "memberId");
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v0.1/merchants/{merchant_code}/members/{member_id}";
-    path = path.replace("{member_id}", ApiClient.urlEncode(String.valueOf(memberId)));
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path = path.replace("{member_id}", ApiClient.urlEncode(ApiClient.parameterValue(memberId)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
 
     this.apiClient.send(HttpMethod.DELETE, path, null, null, null, null, requestOptions);
   }
@@ -161,8 +165,10 @@ public com.sumup.sdk.models.Member getMerchantMember(
     Objects.requireNonNull(memberId, "memberId");
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v0.1/merchants/{merchant_code}/members/{member_id}";
-    path = path.replace("{member_id}", ApiClient.urlEncode(String.valueOf(memberId)));
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path = path.replace("{member_id}", ApiClient.urlEncode(ApiClient.parameterValue(memberId)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
 
     return this.apiClient.send(
         HttpMethod.GET,
@@ -232,7 +238,9 @@ public com.sumup.sdk.models.ListMerchantMembersResponse listMerchantMembers(
       throws ApiException {
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v0.1/merchants/{merchant_code}/members";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
     Map<String, Object> queryParams = new LinkedHashMap<>();
     if (listMerchantMembers != null) {
       queryParams.putAll(listMerchantMembers.toMap());
@@ -296,8 +304,10 @@ public com.sumup.sdk.models.Member updateMerchantMember(
     Objects.requireNonNull(merchantCode, "merchantCode");
     Objects.requireNonNull(request, "request");
     String path = "/v0.1/merchants/{merchant_code}/members/{member_id}";
-    path = path.replace("{member_id}", ApiClient.urlEncode(String.valueOf(memberId)));
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path = path.replace("{member_id}", ApiClient.urlEncode(ApiClient.parameterValue(memberId)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
 
     return this.apiClient.send(
         HttpMethod.PUT,
diff --git a/src/main/java/com/sumup/sdk/clients/MerchantsAsyncClient.java b/src/main/java/com/sumup/sdk/clients/MerchantsAsyncClient.java
index 2aad8ab..7d6cf19 100644
--- a/src/main/java/com/sumup/sdk/clients/MerchantsAsyncClient.java
+++ b/src/main/java/com/sumup/sdk/clients/MerchantsAsyncClient.java
@@ -84,7 +84,9 @@ public CompletableFuture<com.sumup.sdk.models.Merchant> getMerchant(
       throws ApiException {
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v1/merchants/{merchant_code}";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
     Map<String, Object> queryParams = new LinkedHashMap<>();
     if (getMerchant != null) {
       queryParams.putAll(getMerchant.toMap());
@@ -163,8 +165,10 @@ public CompletableFuture<com.sumup.sdk.models.Person> getPerson(
     Objects.requireNonNull(merchantCode, "merchantCode");
     Objects.requireNonNull(personId, "personId");
     String path = "/v1/merchants/{merchant_code}/persons/{person_id}";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
-    path = path.replace("{person_id}", ApiClient.urlEncode(String.valueOf(personId)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
+    path = path.replace("{person_id}", ApiClient.urlEncode(ApiClient.parameterValue(personId)));
     Map<String, Object> queryParams = new LinkedHashMap<>();
     if (getPerson != null) {
       queryParams.putAll(getPerson.toMap());
@@ -239,7 +243,9 @@ public CompletableFuture<com.sumup.sdk.models.ListPersonsResponseBody> listPerso
       throws ApiException {
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v1/merchants/{merchant_code}/persons";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
     Map<String, Object> queryParams = new LinkedHashMap<>();
     if (listPersons != null) {
       queryParams.putAll(listPersons.toMap());
diff --git a/src/main/java/com/sumup/sdk/clients/MerchantsClient.java b/src/main/java/com/sumup/sdk/clients/MerchantsClient.java
index a6f1074..3d5cc53 100644
--- a/src/main/java/com/sumup/sdk/clients/MerchantsClient.java
+++ b/src/main/java/com/sumup/sdk/clients/MerchantsClient.java
@@ -82,7 +82,9 @@ public com.sumup.sdk.models.Merchant getMerchant(
       throws ApiException {
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v1/merchants/{merchant_code}";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
     Map<String, Object> queryParams = new LinkedHashMap<>();
     if (getMerchant != null) {
       queryParams.putAll(getMerchant.toMap());
@@ -161,8 +163,10 @@ public com.sumup.sdk.models.Person getPerson(
     Objects.requireNonNull(merchantCode, "merchantCode");
     Objects.requireNonNull(personId, "personId");
     String path = "/v1/merchants/{merchant_code}/persons/{person_id}";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
-    path = path.replace("{person_id}", ApiClient.urlEncode(String.valueOf(personId)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
+    path = path.replace("{person_id}", ApiClient.urlEncode(ApiClient.parameterValue(personId)));
     Map<String, Object> queryParams = new LinkedHashMap<>();
     if (getPerson != null) {
       queryParams.putAll(getPerson.toMap());
@@ -234,7 +238,9 @@ public com.sumup.sdk.models.ListPersonsResponseBody listPersons(
       throws ApiException {
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v1/merchants/{merchant_code}/persons";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
     Map<String, Object> queryParams = new LinkedHashMap<>();
     if (listPersons != null) {
       queryParams.putAll(listPersons.toMap());
diff --git a/src/main/java/com/sumup/sdk/clients/PayoutsAsyncClient.java b/src/main/java/com/sumup/sdk/clients/PayoutsAsyncClient.java
index b9922a7..2b45270 100644
--- a/src/main/java/com/sumup/sdk/clients/PayoutsAsyncClient.java
+++ b/src/main/java/com/sumup/sdk/clients/PayoutsAsyncClient.java
@@ -186,7 +186,9 @@ public CompletableFuture<com.sumup.sdk.models.FinancialPayouts> listPayoutsV1(
     Objects.requireNonNull(endDate, "endDate");
     Objects.requireNonNull(startDate, "startDate");
     String path = "/v1.0/merchants/{merchant_code}/payouts";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
     Map<String, Object> queryParams = new LinkedHashMap<>();
     queryParams.put("end_date", endDate);
     queryParams.put("start_date", startDate);
diff --git a/src/main/java/com/sumup/sdk/clients/PayoutsClient.java b/src/main/java/com/sumup/sdk/clients/PayoutsClient.java
index ad523cc..9963286 100644
--- a/src/main/java/com/sumup/sdk/clients/PayoutsClient.java
+++ b/src/main/java/com/sumup/sdk/clients/PayoutsClient.java
@@ -185,7 +185,9 @@ public com.sumup.sdk.models.FinancialPayouts listPayoutsV1(
     Objects.requireNonNull(endDate, "endDate");
     Objects.requireNonNull(startDate, "startDate");
     String path = "/v1.0/merchants/{merchant_code}/payouts";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
     Map<String, Object> queryParams = new LinkedHashMap<>();
     queryParams.put("end_date", endDate);
     queryParams.put("start_date", startDate);
diff --git a/src/main/java/com/sumup/sdk/clients/ReadersAsyncClient.java b/src/main/java/com/sumup/sdk/clients/ReadersAsyncClient.java
index fb43978..e3b465d 100644
--- a/src/main/java/com/sumup/sdk/clients/ReadersAsyncClient.java
+++ b/src/main/java/com/sumup/sdk/clients/ReadersAsyncClient.java
@@ -70,7 +70,9 @@ public CompletableFuture<com.sumup.sdk.models.Reader> createReader(
     Objects.requireNonNull(merchantCode, "merchantCode");
     Objects.requireNonNull(request, "request");
     String path = "/v0.1/merchants/{merchant_code}/readers";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
 
     return this.apiClient.sendAsync(
         HttpMethod.POST,
@@ -142,8 +144,10 @@ public CompletableFuture<com.sumup.sdk.models.CreateReaderCheckoutResponse> crea
     Objects.requireNonNull(readerId, "readerId");
     Objects.requireNonNull(request, "request");
     String path = "/v0.1/merchants/{merchant_code}/readers/{reader_id}/checkout";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
-    path = path.replace("{reader_id}", ApiClient.urlEncode(String.valueOf(readerId)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
+    path = path.replace("{reader_id}", ApiClient.urlEncode(ApiClient.parameterValue(readerId)));
 
     return this.apiClient.sendAsync(
         HttpMethod.POST,
@@ -214,8 +218,10 @@ public CompletableFuture<Void> createReaderTerminate(
     Objects.requireNonNull(merchantCode, "merchantCode");
     Objects.requireNonNull(readerId, "readerId");
     String path = "/v0.1/merchants/{merchant_code}/readers/{reader_id}/terminate";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
-    path = path.replace("{reader_id}", ApiClient.urlEncode(String.valueOf(readerId)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
+    path = path.replace("{reader_id}", ApiClient.urlEncode(ApiClient.parameterValue(readerId)));
 
     return this.apiClient.sendAsync(
         HttpMethod.POST, path, null, null, request, null, requestOptions);
@@ -260,8 +266,10 @@ public CompletableFuture<Void> deleteReader(
     Objects.requireNonNull(id, "id");
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v0.1/merchants/{merchant_code}/readers/{id}";
-    path = path.replace("{id}", ApiClient.urlEncode(String.valueOf(id)));
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path = path.replace("{id}", ApiClient.urlEncode(ApiClient.parameterValue(id)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
 
     return this.apiClient.sendAsync(
         HttpMethod.DELETE, path, null, null, null, null, requestOptions);
@@ -331,8 +339,10 @@ public CompletableFuture<com.sumup.sdk.models.Reader> getReader(
     Objects.requireNonNull(id, "id");
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v0.1/merchants/{merchant_code}/readers/{id}";
-    path = path.replace("{id}", ApiClient.urlEncode(String.valueOf(id)));
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path = path.replace("{id}", ApiClient.urlEncode(ApiClient.parameterValue(id)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
     Map<String, String> headerParams = new LinkedHashMap<>();
     if (getReader != null) {
       headerParams.putAll(getReader.toMap());
@@ -402,8 +412,10 @@ public CompletableFuture<com.sumup.sdk.models.StatusResponse> getReaderStatus(
     Objects.requireNonNull(merchantCode, "merchantCode");
     Objects.requireNonNull(readerId, "readerId");
     String path = "/v0.1/merchants/{merchant_code}/readers/{reader_id}/status";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
-    path = path.replace("{reader_id}", ApiClient.urlEncode(String.valueOf(readerId)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
+    path = path.replace("{reader_id}", ApiClient.urlEncode(ApiClient.parameterValue(readerId)));
 
     return this.apiClient.sendAsync(
         HttpMethod.GET,
@@ -452,7 +464,9 @@ public CompletableFuture<com.sumup.sdk.models.ListReadersResponse> listReaders(
       String merchantCode, RequestOptions requestOptions) throws ApiException {
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v0.1/merchants/{merchant_code}/readers";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
 
     return this.apiClient.sendAsync(
         HttpMethod.GET,
@@ -512,8 +526,10 @@ public CompletableFuture<com.sumup.sdk.models.Reader> updateReader(
     Objects.requireNonNull(merchantCode, "merchantCode");
     Objects.requireNonNull(request, "request");
     String path = "/v0.1/merchants/{merchant_code}/readers/{id}";
-    path = path.replace("{id}", ApiClient.urlEncode(String.valueOf(id)));
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path = path.replace("{id}", ApiClient.urlEncode(ApiClient.parameterValue(id)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
 
     return this.apiClient.sendAsync(
         HttpMethod.PATCH,
diff --git a/src/main/java/com/sumup/sdk/clients/ReadersClient.java b/src/main/java/com/sumup/sdk/clients/ReadersClient.java
index b4d1361..a1d3ff7 100644
--- a/src/main/java/com/sumup/sdk/clients/ReadersClient.java
+++ b/src/main/java/com/sumup/sdk/clients/ReadersClient.java
@@ -69,7 +69,9 @@ public com.sumup.sdk.models.Reader createReader(
     Objects.requireNonNull(merchantCode, "merchantCode");
     Objects.requireNonNull(request, "request");
     String path = "/v0.1/merchants/{merchant_code}/readers";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
 
     return this.apiClient.send(
         HttpMethod.POST,
@@ -139,8 +141,10 @@ public com.sumup.sdk.models.CreateReaderCheckoutResponse createReaderCheckout(
     Objects.requireNonNull(readerId, "readerId");
     Objects.requireNonNull(request, "request");
     String path = "/v0.1/merchants/{merchant_code}/readers/{reader_id}/checkout";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
-    path = path.replace("{reader_id}", ApiClient.urlEncode(String.valueOf(readerId)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
+    path = path.replace("{reader_id}", ApiClient.urlEncode(ApiClient.parameterValue(readerId)));
 
     return this.apiClient.send(
         HttpMethod.POST,
@@ -209,8 +213,10 @@ public void createReaderTerminate(
     Objects.requireNonNull(merchantCode, "merchantCode");
     Objects.requireNonNull(readerId, "readerId");
     String path = "/v0.1/merchants/{merchant_code}/readers/{reader_id}/terminate";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
-    path = path.replace("{reader_id}", ApiClient.urlEncode(String.valueOf(readerId)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
+    path = path.replace("{reader_id}", ApiClient.urlEncode(ApiClient.parameterValue(readerId)));
 
     this.apiClient.send(HttpMethod.POST, path, null, null, request, null, requestOptions);
   }
@@ -252,8 +258,10 @@ public void deleteReader(
     Objects.requireNonNull(id, "id");
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v0.1/merchants/{merchant_code}/readers/{id}";
-    path = path.replace("{id}", ApiClient.urlEncode(String.valueOf(id)));
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path = path.replace("{id}", ApiClient.urlEncode(ApiClient.parameterValue(id)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
 
     this.apiClient.send(HttpMethod.DELETE, path, null, null, null, null, requestOptions);
   }
@@ -322,8 +330,10 @@ public com.sumup.sdk.models.Reader getReader(
     Objects.requireNonNull(id, "id");
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v0.1/merchants/{merchant_code}/readers/{id}";
-    path = path.replace("{id}", ApiClient.urlEncode(String.valueOf(id)));
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path = path.replace("{id}", ApiClient.urlEncode(ApiClient.parameterValue(id)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
     Map<String, String> headerParams = new LinkedHashMap<>();
     if (getReader != null) {
       headerParams.putAll(getReader.toMap());
@@ -393,8 +403,10 @@ public com.sumup.sdk.models.StatusResponse getReaderStatus(
     Objects.requireNonNull(merchantCode, "merchantCode");
     Objects.requireNonNull(readerId, "readerId");
     String path = "/v0.1/merchants/{merchant_code}/readers/{reader_id}/status";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
-    path = path.replace("{reader_id}", ApiClient.urlEncode(String.valueOf(readerId)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
+    path = path.replace("{reader_id}", ApiClient.urlEncode(ApiClient.parameterValue(readerId)));
 
     return this.apiClient.send(
         HttpMethod.GET,
@@ -441,7 +453,9 @@ public com.sumup.sdk.models.ListReadersResponse listReaders(
       String merchantCode, RequestOptions requestOptions) throws ApiException {
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v0.1/merchants/{merchant_code}/readers";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
 
     return this.apiClient.send(
         HttpMethod.GET,
@@ -501,8 +515,10 @@ public com.sumup.sdk.models.Reader updateReader(
     Objects.requireNonNull(merchantCode, "merchantCode");
     Objects.requireNonNull(request, "request");
     String path = "/v0.1/merchants/{merchant_code}/readers/{id}";
-    path = path.replace("{id}", ApiClient.urlEncode(String.valueOf(id)));
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path = path.replace("{id}", ApiClient.urlEncode(ApiClient.parameterValue(id)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
 
     return this.apiClient.send(
         HttpMethod.PATCH,
diff --git a/src/main/java/com/sumup/sdk/clients/ReceiptsAsyncClient.java b/src/main/java/com/sumup/sdk/clients/ReceiptsAsyncClient.java
index f92b6ed..37d838b 100644
--- a/src/main/java/com/sumup/sdk/clients/ReceiptsAsyncClient.java
+++ b/src/main/java/com/sumup/sdk/clients/ReceiptsAsyncClient.java
@@ -88,7 +88,7 @@ public CompletableFuture<com.sumup.sdk.models.Receipt> getReceipt(
     Objects.requireNonNull(id, "id");
     Objects.requireNonNull(mid, "mid");
     String path = "/v1.1/receipts/{id}";
-    path = path.replace("{id}", ApiClient.urlEncode(String.valueOf(id)));
+    path = path.replace("{id}", ApiClient.urlEncode(ApiClient.parameterValue(id)));
     Map<String, Object> queryParams = new LinkedHashMap<>();
     queryParams.put("mid", mid);
     if (getReceipt != null) {
diff --git a/src/main/java/com/sumup/sdk/clients/ReceiptsClient.java b/src/main/java/com/sumup/sdk/clients/ReceiptsClient.java
index 2ab61b8..33e60c7 100644
--- a/src/main/java/com/sumup/sdk/clients/ReceiptsClient.java
+++ b/src/main/java/com/sumup/sdk/clients/ReceiptsClient.java
@@ -86,7 +86,7 @@ public com.sumup.sdk.models.Receipt getReceipt(
     Objects.requireNonNull(id, "id");
     Objects.requireNonNull(mid, "mid");
     String path = "/v1.1/receipts/{id}";
-    path = path.replace("{id}", ApiClient.urlEncode(String.valueOf(id)));
+    path = path.replace("{id}", ApiClient.urlEncode(ApiClient.parameterValue(id)));
     Map<String, Object> queryParams = new LinkedHashMap<>();
     queryParams.put("mid", mid);
     if (getReceipt != null) {
diff --git a/src/main/java/com/sumup/sdk/clients/RolesAsyncClient.java b/src/main/java/com/sumup/sdk/clients/RolesAsyncClient.java
index a12fab6..c1b7da0 100644
--- a/src/main/java/com/sumup/sdk/clients/RolesAsyncClient.java
+++ b/src/main/java/com/sumup/sdk/clients/RolesAsyncClient.java
@@ -72,7 +72,9 @@ public CompletableFuture<com.sumup.sdk.models.Role> createMerchantRole(
     Objects.requireNonNull(merchantCode, "merchantCode");
     Objects.requireNonNull(request, "request");
     String path = "/v0.1/merchants/{merchant_code}/roles";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
 
     return this.apiClient.sendAsync(
         HttpMethod.POST,
@@ -122,8 +124,10 @@ public CompletableFuture<Void> deleteMerchantRole(
     Objects.requireNonNull(merchantCode, "merchantCode");
     Objects.requireNonNull(roleId, "roleId");
     String path = "/v0.1/merchants/{merchant_code}/roles/{role_id}";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
-    path = path.replace("{role_id}", ApiClient.urlEncode(String.valueOf(roleId)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
+    path = path.replace("{role_id}", ApiClient.urlEncode(ApiClient.parameterValue(roleId)));
 
     return this.apiClient.sendAsync(
         HttpMethod.DELETE, path, null, null, null, null, requestOptions);
@@ -167,8 +171,10 @@ public CompletableFuture<com.sumup.sdk.models.Role> getMerchantRole(
     Objects.requireNonNull(merchantCode, "merchantCode");
     Objects.requireNonNull(roleId, "roleId");
     String path = "/v0.1/merchants/{merchant_code}/roles/{role_id}";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
-    path = path.replace("{role_id}", ApiClient.urlEncode(String.valueOf(roleId)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
+    path = path.replace("{role_id}", ApiClient.urlEncode(ApiClient.parameterValue(roleId)));
 
     return this.apiClient.sendAsync(
         HttpMethod.GET,
@@ -217,7 +223,9 @@ public CompletableFuture<com.sumup.sdk.models.ListMerchantRolesResponse> listMer
       String merchantCode, RequestOptions requestOptions) throws ApiException {
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v0.1/merchants/{merchant_code}/roles";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
 
     return this.apiClient.sendAsync(
         HttpMethod.GET,
@@ -275,8 +283,10 @@ public CompletableFuture<com.sumup.sdk.models.Role> updateMerchantRole(
     Objects.requireNonNull(roleId, "roleId");
     Objects.requireNonNull(request, "request");
     String path = "/v0.1/merchants/{merchant_code}/roles/{role_id}";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
-    path = path.replace("{role_id}", ApiClient.urlEncode(String.valueOf(roleId)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
+    path = path.replace("{role_id}", ApiClient.urlEncode(ApiClient.parameterValue(roleId)));
 
     return this.apiClient.sendAsync(
         HttpMethod.PATCH,
diff --git a/src/main/java/com/sumup/sdk/clients/RolesClient.java b/src/main/java/com/sumup/sdk/clients/RolesClient.java
index 4da8610..7515c0a 100644
--- a/src/main/java/com/sumup/sdk/clients/RolesClient.java
+++ b/src/main/java/com/sumup/sdk/clients/RolesClient.java
@@ -71,7 +71,9 @@ public com.sumup.sdk.models.Role createMerchantRole(
     Objects.requireNonNull(merchantCode, "merchantCode");
     Objects.requireNonNull(request, "request");
     String path = "/v0.1/merchants/{merchant_code}/roles";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
 
     return this.apiClient.send(
         HttpMethod.POST,
@@ -118,8 +120,10 @@ public void deleteMerchantRole(String merchantCode, String roleId, RequestOption
     Objects.requireNonNull(merchantCode, "merchantCode");
     Objects.requireNonNull(roleId, "roleId");
     String path = "/v0.1/merchants/{merchant_code}/roles/{role_id}";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
-    path = path.replace("{role_id}", ApiClient.urlEncode(String.valueOf(roleId)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
+    path = path.replace("{role_id}", ApiClient.urlEncode(ApiClient.parameterValue(roleId)));
 
     this.apiClient.send(HttpMethod.DELETE, path, null, null, null, null, requestOptions);
   }
@@ -162,8 +166,10 @@ public com.sumup.sdk.models.Role getMerchantRole(
     Objects.requireNonNull(merchantCode, "merchantCode");
     Objects.requireNonNull(roleId, "roleId");
     String path = "/v0.1/merchants/{merchant_code}/roles/{role_id}";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
-    path = path.replace("{role_id}", ApiClient.urlEncode(String.valueOf(roleId)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
+    path = path.replace("{role_id}", ApiClient.urlEncode(ApiClient.parameterValue(roleId)));
 
     return this.apiClient.send(
         HttpMethod.GET,
@@ -210,7 +216,9 @@ public com.sumup.sdk.models.ListMerchantRolesResponse listMerchantRoles(
       String merchantCode, RequestOptions requestOptions) throws ApiException {
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v0.1/merchants/{merchant_code}/roles";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
 
     return this.apiClient.send(
         HttpMethod.GET,
@@ -268,8 +276,10 @@ public com.sumup.sdk.models.Role updateMerchantRole(
     Objects.requireNonNull(roleId, "roleId");
     Objects.requireNonNull(request, "request");
     String path = "/v0.1/merchants/{merchant_code}/roles/{role_id}";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
-    path = path.replace("{role_id}", ApiClient.urlEncode(String.valueOf(roleId)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
+    path = path.replace("{role_id}", ApiClient.urlEncode(ApiClient.parameterValue(roleId)));
 
     return this.apiClient.send(
         HttpMethod.PATCH,
diff --git a/src/main/java/com/sumup/sdk/clients/SubaccountsAsyncClient.java b/src/main/java/com/sumup/sdk/clients/SubaccountsAsyncClient.java
index cfa4b09..1859c7b 100644
--- a/src/main/java/com/sumup/sdk/clients/SubaccountsAsyncClient.java
+++ b/src/main/java/com/sumup/sdk/clients/SubaccountsAsyncClient.java
@@ -63,7 +63,7 @@ public CompletableFuture<com.sumup.sdk.models.Operator> compatGetOperator(
       Integer operatorId, RequestOptions requestOptions) throws ApiException {
     Objects.requireNonNull(operatorId, "operatorId");
     String path = "/v0.1/me/accounts/{operator_id}";
-    path = path.replace("{operator_id}", ApiClient.urlEncode(String.valueOf(operatorId)));
+    path = path.replace("{operator_id}", ApiClient.urlEncode(ApiClient.parameterValue(operatorId)));
 
     return this.apiClient.sendAsync(
         HttpMethod.GET,
@@ -237,7 +237,7 @@ public CompletableFuture<com.sumup.sdk.models.Operator> updateSubAccount(
     Objects.requireNonNull(operatorId, "operatorId");
     Objects.requireNonNull(request, "request");
     String path = "/v0.1/me/accounts/{operator_id}";
-    path = path.replace("{operator_id}", ApiClient.urlEncode(String.valueOf(operatorId)));
+    path = path.replace("{operator_id}", ApiClient.urlEncode(ApiClient.parameterValue(operatorId)));
 
     return this.apiClient.sendAsync(
         HttpMethod.PUT,
diff --git a/src/main/java/com/sumup/sdk/clients/SubaccountsClient.java b/src/main/java/com/sumup/sdk/clients/SubaccountsClient.java
index 6d01315..a16e5d1 100644
--- a/src/main/java/com/sumup/sdk/clients/SubaccountsClient.java
+++ b/src/main/java/com/sumup/sdk/clients/SubaccountsClient.java
@@ -61,7 +61,7 @@ public com.sumup.sdk.models.Operator compatGetOperator(
       Integer operatorId, RequestOptions requestOptions) throws ApiException {
     Objects.requireNonNull(operatorId, "operatorId");
     String path = "/v0.1/me/accounts/{operator_id}";
-    path = path.replace("{operator_id}", ApiClient.urlEncode(String.valueOf(operatorId)));
+    path = path.replace("{operator_id}", ApiClient.urlEncode(ApiClient.parameterValue(operatorId)));
 
     return this.apiClient.send(
         HttpMethod.GET,
@@ -231,7 +231,7 @@ public com.sumup.sdk.models.Operator updateSubAccount(
     Objects.requireNonNull(operatorId, "operatorId");
     Objects.requireNonNull(request, "request");
     String path = "/v0.1/me/accounts/{operator_id}";
-    path = path.replace("{operator_id}", ApiClient.urlEncode(String.valueOf(operatorId)));
+    path = path.replace("{operator_id}", ApiClient.urlEncode(ApiClient.parameterValue(operatorId)));
 
     return this.apiClient.send(
         HttpMethod.PUT,
diff --git a/src/main/java/com/sumup/sdk/clients/TransactionsAsyncClient.java b/src/main/java/com/sumup/sdk/clients/TransactionsAsyncClient.java
index 9834ef1..d085d94 100644
--- a/src/main/java/com/sumup/sdk/clients/TransactionsAsyncClient.java
+++ b/src/main/java/com/sumup/sdk/clients/TransactionsAsyncClient.java
@@ -180,7 +180,9 @@ public CompletableFuture<com.sumup.sdk.models.TransactionFull> getTransactionV21
       throws ApiException {
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v2.1/merchants/{merchant_code}/transactions";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
     Map<String, Object> queryParams = new LinkedHashMap<>();
     if (getTransactionV21 != null) {
       queryParams.putAll(getTransactionV21.toMap());
@@ -328,7 +330,9 @@ public CompletableFuture<com.sumup.sdk.models.ListTransactionsV21Response> listT
       throws ApiException {
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v2.1/merchants/{merchant_code}/transactions/history";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
     Map<String, Object> queryParams = new LinkedHashMap<>();
     if (listTransactionsV21 != null) {
       queryParams.putAll(listTransactionsV21.toMap());
@@ -384,7 +388,7 @@ public CompletableFuture<Void> refundTransaction(
       throws ApiException {
     Objects.requireNonNull(txnId, "txnId");
     String path = "/v0.1/me/refund/{txn_id}";
-    path = path.replace("{txn_id}", ApiClient.urlEncode(String.valueOf(txnId)));
+    path = path.replace("{txn_id}", ApiClient.urlEncode(ApiClient.parameterValue(txnId)));
 
     return this.apiClient.sendAsync(
         HttpMethod.POST, path, null, null, request, null, requestOptions);
diff --git a/src/main/java/com/sumup/sdk/clients/TransactionsClient.java b/src/main/java/com/sumup/sdk/clients/TransactionsClient.java
index 7562d78..031bad5 100644
--- a/src/main/java/com/sumup/sdk/clients/TransactionsClient.java
+++ b/src/main/java/com/sumup/sdk/clients/TransactionsClient.java
@@ -178,7 +178,9 @@ public com.sumup.sdk.models.TransactionFull getTransactionV21(
       throws ApiException {
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v2.1/merchants/{merchant_code}/transactions";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
     Map<String, Object> queryParams = new LinkedHashMap<>();
     if (getTransactionV21 != null) {
       queryParams.putAll(getTransactionV21.toMap());
@@ -319,7 +321,9 @@ public com.sumup.sdk.models.ListTransactionsV21Response listTransactionsV21(
       throws ApiException {
     Objects.requireNonNull(merchantCode, "merchantCode");
     String path = "/v2.1/merchants/{merchant_code}/transactions/history";
-    path = path.replace("{merchant_code}", ApiClient.urlEncode(String.valueOf(merchantCode)));
+    path =
+        path.replace(
+            "{merchant_code}", ApiClient.urlEncode(ApiClient.parameterValue(merchantCode)));
     Map<String, Object> queryParams = new LinkedHashMap<>();
     if (listTransactionsV21 != null) {
       queryParams.putAll(listTransactionsV21.toMap());
@@ -373,7 +377,7 @@ public void refundTransaction(
       throws ApiException {
     Objects.requireNonNull(txnId, "txnId");
     String path = "/v0.1/me/refund/{txn_id}";
-    path = path.replace("{txn_id}", ApiClient.urlEncode(String.valueOf(txnId)));
+    path = path.replace("{txn_id}", ApiClient.urlEncode(ApiClient.parameterValue(txnId)));
 
     this.apiClient.send(HttpMethod.POST, path, null, null, request, null, requestOptions);
   }
diff --git a/src/main/java/com/sumup/sdk/core/ApiClient.java b/src/main/java/com/sumup/sdk/core/ApiClient.java
index f35d07d..9d7bcbf 100644
--- a/src/main/java/com/sumup/sdk/core/ApiClient.java
+++ b/src/main/java/com/sumup/sdk/core/ApiClient.java
@@ -279,6 +279,26 @@ public static String urlEncode(String value) {
     return URLEncoder.encode(value, StandardCharsets.UTF_8);
   }
 
+  public static String parameterValue(Object value) {
+    Object unwrapped = unwrapSingleValueRecord(value);
+    return unwrapped == null ? null : unwrapped.toString();
+  }
+
+  private static Object unwrapSingleValueRecord(Object value) {
+    if (value == null || !value.getClass().isRecord()) {
+      return value;
+    }
+    var components = value.getClass().getRecordComponents();
+    if (components.length != 1 || !"value".equals(components[0].getName())) {
+      return value;
+    }
+    try {
+      return components[0].getAccessor().invoke(value);
+    } catch (ReflectiveOperationException e) {
+      throw new ApiException("Failed to serialize request parameter", e);
+    }
+  }
+
   public static String headerValue(Object value) {
     if (value == null) {
       return null;
diff --git a/src/test/java/com/sumup/sdk/core/ApiClientTest.java b/src/test/java/com/sumup/sdk/core/ApiClientTest.java
index b8e36a1..cf42b3d 100644
--- a/src/test/java/com/sumup/sdk/core/ApiClientTest.java
+++ b/src/test/java/com/sumup/sdk/core/ApiClientTest.java
@@ -3,6 +3,8 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import com.sumup.sdk.clients.ReadersClient;
+import com.sumup.sdk.models.ReaderId;
 import java.net.Authenticator;
 import java.net.CookieHandler;
 import java.net.ProxySelector;
@@ -110,6 +112,19 @@ void requestOptionsCanOverrideTimeout() {
     assertEquals(timeout, httpClient.lastRequest().timeout().get());
   }
 
+  @Test
+  void pathParamsUnwrapSingleValueRecords() {
+    CapturingHttpClient httpClient = new CapturingHttpClient();
+    ApiClient apiClient = ApiClient.builder().httpClient(httpClient).build();
+    ReadersClient readersClient = new ReadersClient(apiClient);
+
+    readersClient.deleteReader(new ReaderId("reader 123"), "merchant-code");
+
+    assertEquals(
+        URI.create("https://api.sumup.com/v0.1/merchants/merchant-code/readers/reader+123"),
+        httpClient.lastRequest().uri());
+  }
+
   private static final class CapturingHttpClient extends HttpClient {
     private HttpRequest lastRequest;