diff --git a/src/service/DatasetService.ts b/src/service/DatasetService.ts
index 75b6d6b244e91c6d2c6e93f00e791abb98a8e0be..b89866b9dbf7972ef1d35562ea849184f7cf19dd 100644
--- a/src/service/DatasetService.ts
+++ b/src/service/DatasetService.ts
@@ -22,7 +22,7 @@ export class DatasetService {
       l: results,
       d: order,
       s: sortBy,
-      f: typeof filter === 'string' ? filter : null,
+      f: typeof filter === 'string' ? filter : undefined,
     });
     return authenticatedRequest(token, {
       url: `${MY_DATASETS_LIST_URL}?${query}`,
diff --git a/src/service/DescriptorListService.ts b/src/service/DescriptorListService.ts
index 95545d6c5cedfc0b89124d576c4fea17db585894..6eff2f0041b9539220ba4b17ccdf73f0a4f48550 100644
--- a/src/service/DescriptorListService.ts
+++ b/src/service/DescriptorListService.ts
@@ -24,7 +24,7 @@ export class DescriptorListService {
       l: results,
       d: order,
       s: sortBy,
-      f: typeof filter === 'string' ? filter : null,
+      f: typeof filter === 'string' ? filter : undefined,
     });
     // console.log('Query', query);
 
diff --git a/src/service/DescriptorService.ts b/src/service/DescriptorService.ts
index b6858ef8ac066742ace03918f908fa6b62ca6be2..c5b16e4acf345132645059c4f22441d4684b0d06 100644
--- a/src/service/DescriptorService.ts
+++ b/src/service/DescriptorService.ts
@@ -33,7 +33,7 @@ export class DescriptorService {
       l: results,
       d: order,
       s: sortBy,
-      f: typeof filter === 'string' ? filter : null,
+      f: typeof filter === 'string' ? filter : undefined,
     });
     // console.log('Query', query);
     return authenticatedRequest(token, {