diff --git a/src/ovoid/services/payment.py b/src/ovoid/services/payment.py
index aa59488..f41d203 100644
--- a/src/ovoid/services/payment.py
+++ b/src/ovoid/services/payment.py
@@ -29,6 +29,11 @@ class PaymentService:
     def __init__(self, client: OVOClient) -> None:
         self._client = client
 
+    @staticmethod
+    def _path_segment(value: str) -> str:
+        """Encode an identifier before inserting it into a URL path."""
+        return quote(value, safe="")
+
     def do_qr_payment(
         self,
         body_request: dict[str, Any],
@@ -67,15 +72,17 @@ def get_payment_method(self) -> dict[str, Any]:
 
     def get_payment_method_by_merchant(self, merchant_id: str) -> dict[str, Any]:
         """``GET wallet/payment-method/merchant/{id}``."""
-        return self._client.get(self._PATH_PAYMENT_METHOD_MERCHANT + merchant_id)
+        return self._client.get(self._PATH_PAYMENT_METHOD_MERCHANT + self._path_segment(merchant_id))
 
     def get_payment_method_by_merchant_deal(self, merchant_id: str, deal_id: str) -> dict[str, Any]:
         """``GET wallet/payment-method/merchant/{id}/deals/{deal_id}``."""
-        return self._client.get(self._PATH_PAYMENT_METHOD_MERCHANT + merchant_id + "/deals/" + deal_id)
+        merchant = self._path_segment(merchant_id)
+        deal = self._path_segment(deal_id)
+        return self._client.get(self._PATH_PAYMENT_METHOD_MERCHANT + merchant + "/deals/" + deal)
 
     def get_remaining_timeout(self, order_id: str) -> dict[str, Any]:
         """Remaining order time (``GET wallet/order/{orderID}/expiry``)."""
-        return self._client.get(self._PATH_ORDER_EXPIRY + order_id + "/expiry")
+        return self._client.get(self._PATH_ORDER_EXPIRY + self._path_segment(order_id) + "/expiry")
 
     def get_tip(self, client_id: str, request: dict[str, Any]) -> dict[str, Any]:
         """Suggested tip (``POST v1.0/reference/master/amounts`` with ``clientId`` header)."""