diff --git a/PocketCsvReader.Testing/Configuration/SchemaDescriptionBuilderTest.cs b/PocketCsvReader.Testing/Configuration/SchemaDescriptionBuilderTest.cs
index 90288a0..5502bb9 100644
--- a/PocketCsvReader.Testing/Configuration/SchemaDescriptionBuilderTest.cs
+++ b/PocketCsvReader.Testing/Configuration/SchemaDescriptionBuilderTest.cs
@@ -96,6 +96,32 @@ public void NamedWithFields_ShouldSetFields()
             Assert.That(field.Name, Is.Not.Null.Or.Empty);
     }
 
+    private static IEnumerable<ISchemaDescriptorBuilder> CreateBuilder()
+    {
+        yield return new SchemaDescriptorBuilder().Named();
+        yield return new SchemaDescriptorBuilder().Indexed();
+    }
+
+    [Test]
+    [TestCaseSource(nameof(CreateBuilder))]
+    public void InterfaceWithFields_ShouldSetFields(ISchemaDescriptorBuilder builder)
+    {
+        builder.WithField(typeof(int), "foo", (x) => x);
+        builder.WithField(typeof(DateTime), "bar", (f) => f.WithFormat("%Y-%M-%d"));
+        var descriptor = builder.Build();
+        Assert.That(descriptor, Is.Not.Null);
+        Assert.That(descriptor!.Fields, Has.Length.EqualTo(2));
+        Assert.That(descriptor.Fields["foo"].RuntimeType, Is.EqualTo(typeof(int)));
+        Assert.That(descriptor.Fields["foo"].Name, Is.EqualTo("foo"));
+        Assert.That(descriptor.Fields["foo"].Format, Is.Null);
+        Assert.That(descriptor.Fields["bar"].RuntimeType, Is.EqualTo(typeof(DateTime)));
+        Assert.That(descriptor.Fields["bar"].Name, Is.EqualTo("bar"));
+        Assert.That(descriptor.Fields["bar"].Format, Is.EqualTo("%Y-%M-%d"));
+
+        foreach (var field in descriptor.Fields)
+            Assert.That(field.Name, Is.Not.Null.Or.Empty);
+    }
+
     [Test]
     public void DuplicateNames_ShouldThrow()
     {
diff --git a/PocketCsvReader/Configuration/FieldCollectionDescriptor.cs b/PocketCsvReader/Configuration/FieldCollectionDescriptor.cs
index 8eeefa9..c267a75 100644
--- a/PocketCsvReader/Configuration/FieldCollectionDescriptor.cs
+++ b/PocketCsvReader/Configuration/FieldCollectionDescriptor.cs
@@ -70,7 +70,7 @@ public override FieldDescriptor this[int index]
 
         public override FieldDescriptor this[string name]
         {
-            get => throw new NotSupportedException();
+            get => _list.FirstOrDefault(f => f.Name == name) ?? throw new KeyNotFoundException($"Field '{name}' not found.");
         }
 
         public override bool TryGetValue(string name, [NotNullWhen(true)] out FieldDescriptor? field)
diff --git a/PocketCsvReader/Configuration/SchemaDescriptorBuilder.cs b/PocketCsvReader/Configuration/SchemaDescriptorBuilder.cs
index 1733560..ec18b9b 100644
--- a/PocketCsvReader/Configuration/SchemaDescriptorBuilder.cs
+++ b/PocketCsvReader/Configuration/SchemaDescriptorBuilder.cs
@@ -18,6 +18,7 @@ public NamedSchemaDescriptorBuilder Named()
 public interface ISchemaDescriptorBuilder
 {
     SchemaDescriptor? Build();
+    ISchemaDescriptorBuilder WithField(Type type, string name, Func<FieldDescriptorBuilder, FieldDescriptorBuilder> func);
 }
 
 public class IndexedSchemaDescriptorBuilder : ISchemaDescriptorBuilder
@@ -40,6 +41,12 @@ public IndexedSchemaDescriptorBuilder WithField(Type type, Func<FieldDescriptorB
         return this;
     }
 
+    public IndexedSchemaDescriptorBuilder WithField(Type type, string name, Func<FieldDescriptorBuilder, FieldDescriptorBuilder> func)
+        => WithField(type, (builder) => func(builder.WithName(name)));
+
+    ISchemaDescriptorBuilder ISchemaDescriptorBuilder.WithField(Type type, string name, Func<FieldDescriptorBuilder, FieldDescriptorBuilder> func)
+        => WithField(type, name, func);
+
     public SchemaDescriptor? Build()
     {
         foreach (var field in _fields)
@@ -58,11 +65,17 @@ public NamedSchemaDescriptorBuilder WithField<T>(string name)
         => WithField<T>(name, x => x);
 
     public NamedSchemaDescriptorBuilder WithField<T>(string name, Func<FieldDescriptorBuilder, FieldDescriptorBuilder> func)
+        => WithField(typeof(T), name, func);
+
+    public NamedSchemaDescriptorBuilder WithField(Type type, string name, Func<FieldDescriptorBuilder, FieldDescriptorBuilder> func)
     {
-        _fields.Add(func(new FieldDescriptorBuilder(typeof(T)).WithName(name)));
+        _fields.Add(func(new FieldDescriptorBuilder(type).WithName(name)));
         return this;
     }
 
+    ISchemaDescriptorBuilder ISchemaDescriptorBuilder.WithField(Type type, string name, Func<FieldDescriptorBuilder, FieldDescriptorBuilder> func)
+        => WithField(type, name, func);
+
     public SchemaDescriptor? Build()
     {
         foreach (var field in _fields)