diff --git a/services/bff/Bff.Api/DownstreamClients.cs b/services/bff/Bff.Api/DownstreamClients.cs
index a2d8151..f9761d5 100644
--- a/services/bff/Bff.Api/DownstreamClients.cs
+++ b/services/bff/Bff.Api/DownstreamClients.cs
@@ -54,6 +54,19 @@ public interface IProjectionClient
     Task<IReadOnlyList<ProjectionEntry>> GetRegisterAsync(CancellationToken ct = default);
 }
 
+/// <summary>A published zaaktype as the beheer catalogus viewer shows it (S-15a): the business
+/// <c>Identificatie</c> + human <c>Omschrijving</c>. The ZGW URL the ACL also returns is dropped — an
+/// internal reference, not shown in the portal.</summary>
+public sealed record BeheerZaaktype(string Identificatie, string Omschrijving);
+
+/// <summary>Port to the ACL for read-only catalogus queries (beheer portal, S-15a). The BFF reaches the
+/// ACL directly for this read: the catalogus isn't a domain concern, and the ACL is the only code
+/// allowed to read the ZGW Catalogi API (§8.1, ADR-0025).</summary>
+public interface IAclClient
+{
+    Task<IReadOnlyList<BeheerZaaktype>> GetZaaktypenAsync(CancellationToken ct = default);
+}
+
 /// <summary>Calls the Domain Service's <c>POST /registrations</c>.</summary>
 public sealed class DomainClient(HttpClient http) : IDomainClient
 {
@@ -121,3 +134,11 @@ public sealed class ProjectionClient(HttpClient http) : IProjectionClient
     public async Task<IReadOnlyList<ProjectionEntry>> GetRegisterAsync(CancellationToken ct = default)
         => await http.GetFromJsonAsync<List<ProjectionEntry>>("register", ct) ?? [];
 }
+
+/// <summary>Calls the ACL's <c>GET /catalogi/zaaktypen</c> (S-15a). The ACL also returns each zaaktype's
+/// ZGW URL; deserializing into <see cref="BeheerZaaktype"/> keeps only the public-safe fields.</summary>
+public sealed class AclClient(HttpClient http) : IAclClient
+{
+    public async Task<IReadOnlyList<BeheerZaaktype>> GetZaaktypenAsync(CancellationToken ct = default)
+        => await http.GetFromJsonAsync<List<BeheerZaaktype>>("catalogi/zaaktypen", ct) ?? [];
+}
diff --git a/services/bff/Bff.Tests/BeheerEndpointTests.cs b/services/bff/Bff.Tests/BeheerEndpointTests.cs
new file mode 100644
index 0000000..ee884de
--- /dev/null
+++ b/services/bff/Bff.Tests/BeheerEndpointTests.cs
@@ -0,0 +1,57 @@
+using System.Net;
+using System.Net.Http.Headers;
+using System.Net.Http.Json;
+using Bff.Api;
+
+namespace Bff.Tests;
+
+/// <summary>
+/// The beheer catalogus viewer (S-15a): reached only with a medewerker-realm token carrying the
+/// <c>beheerder</c> role. A missing token is 401; an authenticated medewerker without the role (e.g.
+/// a plain behandelaar) is 403; a beheerder gets the read-only list of published zaaktypen.
+/// </summary>
+public class BeheerEndpointTests
+{
+    private static HttpRequestMessage Zaaktypen(string? bearer)
+    {
+        var request = new HttpRequestMessage(HttpMethod.Get, "/beheer/catalogi/zaaktypen");
+        if (bearer is not null)
+            request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", bearer);
+        return request;
+    }
+
+    [Fact]
+    public async Task Rejects_the_catalogus_without_a_token()
+    {
+        using var factory = new BffFactory();
+
+        var response = await factory.CreateClient().SendAsync(Zaaktypen(bearer: null));
+
+        Assert.Equal(HttpStatusCode.Unauthorized, response.StatusCode);
+    }
+
+    [Fact]
+    public async Task Rejects_a_medewerker_without_the_beheerder_role()
+    {
+        using var factory = new BffFactory();
+
+        var response = await factory.CreateClient().SendAsync(Zaaktypen(TestTokens.Medewerker("behandelaar")));
+
+        Assert.Equal(HttpStatusCode.Forbidden, response.StatusCode);
+    }
+
+    [Fact]
+    public async Task Serves_the_published_zaaktypen_to_a_beheerder()
+    {
+        using var factory = new BffFactory();
+        factory.Acl.Zaaktypen.Add(new BeheerZaaktype("BIG-REGISTRATIE", "BIG-registratie"));
+
+        var response = await factory.CreateClient().SendAsync(Zaaktypen(TestTokens.Medewerker("beheerder")));
+
+        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+        var items = await response.Content.ReadFromJsonAsync<List<BeheerZaaktype>>();
+        var item = Assert.Single(items!);
+        Assert.Equal("BIG-REGISTRATIE", item.Identificatie);
+        Assert.Equal("BIG-registratie", item.Omschrijving);
+    }
+}
diff --git a/services/bff/Bff.Tests/BffFactory.cs b/services/bff/Bff.Tests/BffFactory.cs
index 7985ba1..7f1141e 100644
--- a/services/bff/Bff.Tests/BffFactory.cs
+++ b/services/bff/Bff.Tests/BffFactory.cs
@@ -23,6 +23,7 @@ internal sealed class BffFactory : WebApplicationFactory<Program>
 
     public FakeDomainClient Domain { get; } = new();
     public FakeProjectionClient Projection { get; } = new();
+    public FakeAclClient Acl { get; } = new();
 
     private static void ValidateWithTestKey(IServiceCollection services, string scheme) =>
         services.Configure<JwtBearerOptions>(scheme, options =>
@@ -54,11 +55,13 @@ internal sealed class BffFactory : WebApplicationFactory<Program>
         builder.UseSetting("Keycloak:MedewerkerAuthority", "https://keycloak.invalid/realms/medewerker");
         builder.UseSetting("Downstream:Domain:BaseUrl", "http://domain.invalid/");
         builder.UseSetting("Downstream:Projection:BaseUrl", "http://projection.invalid/");
+        builder.UseSetting("Downstream:Acl:BaseUrl", "http://acl.invalid/");
 
         builder.ConfigureTestServices(services =>
         {
             services.AddSingleton<IDomainClient>(Domain);
             services.AddSingleton<IProjectionClient>(Projection);
+            services.AddSingleton<IAclClient>(Acl);
 
             // Both realms validate locally against the test key (no live Keycloak). The medewerker
             // scheme keeps its OnTokenValidated role-lifting from Program.cs — only the validation
@@ -138,3 +141,12 @@ internal sealed class FakeProjectionClient : IProjectionClient
     public Task<IReadOnlyList<ProjectionEntry>> GetRegisterAsync(CancellationToken ct = default)
         => Task.FromResult<IReadOnlyList<ProjectionEntry>>(Entries);
 }
+
+/// <summary>Serves a configurable set of catalogus zaaktypen (beheer viewer, S-15a).</summary>
+internal sealed class FakeAclClient : IAclClient
+{
+    public List<BeheerZaaktype> Zaaktypen { get; } = [];
+
+    public Task<IReadOnlyList<BeheerZaaktype>> GetZaaktypenAsync(CancellationToken ct = default)
+        => Task.FromResult<IReadOnlyList<BeheerZaaktype>>(Zaaktypen);
+}