diff --git a/libs/api-client/src/lib/generated/bff-api.ts b/libs/api-client/src/lib/generated/bff-api.ts
index 1828d6e..e806978 100644
--- a/libs/api-client/src/lib/generated/bff-api.ts
+++ b/libs/api-client/src/lib/generated/bff-api.ts
@@ -24,6 +24,12 @@ import {
   Observable
 } from 'rxjs';
 
+export interface BeheerDefaultFill {
+  bronorganisatie: string;
+  verantwoordelijkeOrganisatie: string;
+  vertrouwelijkheidaanduiding: string;
+}
+
 export interface BeheerZaaktype {
   identificatie: string;
   omschrijving: string;
@@ -446,4 +452,69 @@ export class BffApiV1Service {
     );
   }
 
+ getBeheerDefaultFill<TData = BeheerDefaultFill>( options?: HttpClientBodyOptions): Observable<TData>;
+ getBeheerDefaultFill<TData = BeheerDefaultFill>( options?: HttpClientEventOptions): Observable<HttpEvent<TData>>;
+ getBeheerDefaultFill<TData = BeheerDefaultFill>( options?: HttpClientResponseOptions): Observable<AngularHttpResponse<TData>>;
+  getBeheerDefaultFill<TData = BeheerDefaultFill>(
+     options?: HttpClientObserveOptions): Observable<TData | HttpEvent<TData> | AngularHttpResponse<TData>> {
+    if (options?.observe === 'events') {
+      return this.http.get<TData>(
+      `/beheer/default-fill`,{
+        ...(options as Omit<NonNullable<typeof options>, 'observe'>),
+        observe: 'events',
+      }
+    );
+    }
+
+    if (options?.observe === 'response') {
+      return this.http.get<TData>(
+      `/beheer/default-fill`,{
+        ...(options as Omit<NonNullable<typeof options>, 'observe'>),
+        observe: 'response',
+      }
+    );
+    }
+
+    return this.http.get<TData>(
+      `/beheer/default-fill`,{
+        ...(options as Omit<NonNullable<typeof options>, 'observe'>),
+        observe: 'body',
+      }
+    );
+  }
+
+ putBeheerDefaultFill<TData = void>(beheerDefaultFill: BeheerDefaultFill, options?: HttpClientBodyOptions): Observable<TData>;
+ putBeheerDefaultFill<TData = void>(beheerDefaultFill: BeheerDefaultFill, options?: HttpClientEventOptions): Observable<HttpEvent<TData>>;
+ putBeheerDefaultFill<TData = void>(beheerDefaultFill: BeheerDefaultFill, options?: HttpClientResponseOptions): Observable<AngularHttpResponse<TData>>;
+  putBeheerDefaultFill<TData = void>(
+    beheerDefaultFill: BeheerDefaultFill, options?: HttpClientObserveOptions): Observable<TData | HttpEvent<TData> | AngularHttpResponse<TData>> {
+    if (options?.observe === 'events') {
+      return this.http.put<TData>(
+      `/beheer/default-fill`,
+      beheerDefaultFill,{
+        ...(options as Omit<NonNullable<typeof options>, 'observe'>),
+        observe: 'events',
+      }
+    );
+    }
+
+    if (options?.observe === 'response') {
+      return this.http.put<TData>(
+      `/beheer/default-fill`,
+      beheerDefaultFill,{
+        ...(options as Omit<NonNullable<typeof options>, 'observe'>),
+        observe: 'response',
+      }
+    );
+    }
+
+    return this.http.put<TData>(
+      `/beheer/default-fill`,
+      beheerDefaultFill,{
+        ...(options as Omit<NonNullable<typeof options>, 'observe'>),
+        observe: 'body',
+      }
+    );
+  }
+
 };
diff --git a/services/bff/Bff.Api/Program.cs b/services/bff/Bff.Api/Program.cs
index dd9a8f2..ee2a36e 100644
--- a/services/bff/Bff.Api/Program.cs
+++ b/services/bff/Bff.Api/Program.cs
@@ -228,6 +228,25 @@ app.MapGet("/beheer/catalogi/zaaktypen", async (IAclClient acl, CancellationToke
     .Produces(StatusCodes.Status401Unauthorized)
     .Produces(StatusCodes.Status403Forbidden);
 
+// Beheer default-fill config (S-15b): read + edit the ACL's default-fill values. Behind medewerker-
+// realm + beheerder authorization; the BFF proxies the ACL (ADR-0025). The ACL validates the values.
+app.MapGet("/beheer/default-fill", async (IAclClient acl, CancellationToken ct) =>
+    Results.Ok(await acl.GetDefaultFillAsync(ct)))
+    .RequireAuthorization(BeheerAuth.Policy)
+    .Produces<BeheerDefaultFill>(StatusCodes.Status200OK)
+    .Produces(StatusCodes.Status401Unauthorized)
+    .Produces(StatusCodes.Status403Forbidden);
+
+app.MapPut("/beheer/default-fill", async (BeheerDefaultFill body, IAclClient acl, CancellationToken ct) =>
+{
+    await acl.UpdateDefaultFillAsync(body, ct);
+    return Results.NoContent();
+})
+    .RequireAuthorization(BeheerAuth.Policy)
+    .Produces(StatusCodes.Status204NoContent)
+    .Produces(StatusCodes.Status401Unauthorized)
+    .Produces(StatusCodes.Status403Forbidden);
+
 app.Run();
 
 /// <summary>The behandelaar's decision on a registration.</summary>
diff --git a/services/bff/openapi.json b/services/bff/openapi.json
index 10b790d..a9a985c 100644
--- a/services/bff/openapi.json
+++ b/services/bff/openapi.json
@@ -255,10 +255,80 @@
           }
         }
       }
+    },
+    "/beheer/default-fill": {
+      "get": {
+        "tags": [
+          "Bff.Api"
+        ],
+        "responses": {
+          "200": {
+            "description": "OK",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/BeheerDefaultFill"
+                }
+              }
+            }
+          },
+          "401": {
+            "description": "Unauthorized"
+          },
+          "403": {
+            "description": "Forbidden"
+          }
+        }
+      },
+      "put": {
+        "tags": [
+          "Bff.Api"
+        ],
+        "requestBody": {
+          "content": {
+            "application/json": {
+              "schema": {
+                "$ref": "#/components/schemas/BeheerDefaultFill"
+              }
+            }
+          },
+          "required": true
+        },
+        "responses": {
+          "204": {
+            "description": "No Content"
+          },
+          "401": {
+            "description": "Unauthorized"
+          },
+          "403": {
+            "description": "Forbidden"
+          }
+        }
+      }
     }
   },
   "components": {
     "schemas": {
+      "BeheerDefaultFill": {
+        "required": [
+          "bronorganisatie",
+          "verantwoordelijkeOrganisatie",
+          "vertrouwelijkheidaanduiding"
+        ],
+        "type": "object",
+        "properties": {
+          "bronorganisatie": {
+            "type": "string"
+          },
+          "verantwoordelijkeOrganisatie": {
+            "type": "string"
+          },
+          "vertrouwelijkheidaanduiding": {
+            "type": "string"
+          }
+        }
+      },
       "BeheerZaaktype": {
         "required": [
           "identificatie",