diff --git a/ndc-http-schema/openapi/internal/oas2_schema.go b/ndc-http-schema/openapi/internal/oas2_schema.go
index cff0192..4dffbd2 100644
--- a/ndc-http-schema/openapi/internal/oas2_schema.go
+++ b/ndc-http-schema/openapi/internal/oas2_schema.go
@@ -60,44 +60,41 @@ func (oc *oas2SchemaBuilder) getSchemaTypeFromParameter(param *v2.Parameter, fie
 }
 
 // get and convert an OpenAPI data type to a NDC type
-func (oc *oas2SchemaBuilder) getSchemaType(typeSchema *base.Schema, fieldPaths []string) (*SchemaInfoCache, error) {
-	if typeSchema == nil {
+func (oc *oas2SchemaBuilder) getSchemaType(baseSchema *base.Schema, fieldPaths []string) (*SchemaInfoCache, error) {
+	if baseSchema == nil {
 		return nil, errParameterSchemaEmpty(fieldPaths)
 	}
 
-	if oc.builder.ConvertOptions.NoDeprecation && typeSchema.Deprecated != nil && *typeSchema.Deprecated {
+	if oc.builder.ConvertOptions.NoDeprecation && baseSchema.Deprecated != nil && *baseSchema.Deprecated {
 		return nil, nil
 	}
 
-	if len(typeSchema.AllOf) > 0 {
-		return oc.buildUnionSchemaType(typeSchema, typeSchema.AllOf, oasAllOf, fieldPaths)
+	if len(baseSchema.AllOf) > 0 {
+		return oc.buildUnionSchemaType(baseSchema, baseSchema.AllOf, oasAllOf, fieldPaths)
 	}
 
-	if len(typeSchema.AnyOf) > 0 {
-		return oc.buildUnionSchemaType(typeSchema, typeSchema.AnyOf, oasAnyOf, fieldPaths)
+	if len(baseSchema.AnyOf) > 0 {
+		return oc.buildUnionSchemaType(baseSchema, baseSchema.AnyOf, oasAnyOf, fieldPaths)
 	}
 
-	if len(typeSchema.OneOf) > 0 {
-		return oc.buildUnionSchemaType(typeSchema, typeSchema.OneOf, oasOneOf, fieldPaths)
+	if len(baseSchema.OneOf) > 0 {
+		return oc.buildUnionSchemaType(baseSchema, baseSchema.OneOf, oasOneOf, fieldPaths)
 	}
 
-	oasTypes, nullable := extractNullableFromOASTypes(typeSchema.Type)
-	nullable = nullable || (typeSchema.Nullable != nil && *typeSchema.Nullable)
-	if typeSchema.AdditionalProperties != nil && (typeSchema.AdditionalProperties.B || typeSchema.AdditionalProperties.A != nil) {
-		var result schema.TypeEncoder = oc.builder.buildScalarJSON()
-		if nullable {
-			result = schema.NewNullableType(result)
-		}
+	oasTypes, nullable := extractNullableFromOASTypes(baseSchema.Type)
+	nullable = nullable || (baseSchema.Nullable != nil && *baseSchema.Nullable)
 
-		return &SchemaInfoCache{
-			TypeRead:   result,
-			TypeWrite:  result,
-			TypeSchema: createSchemaFromOpenAPISchema(typeSchema),
-		}, nil
+	if len(oasTypes) == 0 {
+		// if the OAS schema has properties or items we can consider this type as an object or array
+		if baseSchema.Properties != nil && baseSchema.Properties.Len() > 0 {
+			oasTypes = []string{"object"}
+		} else if baseSchema.Items != nil && baseSchema.Items.A != nil {
+			oasTypes = []string{"array"}
+		}
 	}
 
 	if len(oasTypes) != 1 || isPrimitiveScalar(oasTypes) {
-		scalarName := getScalarFromType(oc.builder.schema, oasTypes, typeSchema.Format, typeSchema.Enum, fieldPaths)
+		scalarName := getScalarFromType(oc.builder.schema, oasTypes, baseSchema.Format, baseSchema.Enum, fieldPaths)
 		var resultType schema.TypeEncoder = schema.NewNamedType(scalarName)
 		if nullable {
 			resultType = schema.NewNullableType(resultType)
@@ -106,7 +103,7 @@ func (oc *oas2SchemaBuilder) getSchemaType(typeSchema *base.Schema, fieldPaths [
 		return &SchemaInfoCache{
 			TypeRead:   resultType,
 			TypeWrite:  resultType,
-			TypeSchema: createSchemaFromOpenAPISchema(typeSchema),
+			TypeSchema: createSchemaFromOpenAPISchema(baseSchema),
 		}, nil
 	}
 
@@ -115,14 +112,14 @@ func (oc *oas2SchemaBuilder) getSchemaType(typeSchema *base.Schema, fieldPaths [
 	typeName := oasTypes[0]
 	switch typeName {
 	case "object":
-		typeResult, err = oc.evalObjectType(typeSchema, fieldPaths)
+		typeResult, err = oc.evalObjectType(baseSchema, fieldPaths)
 		if err != nil {
 			return nil, err
 		}
 	case "array":
 		var itemSchema *SchemaInfoCache
-		if typeSchema.Items != nil || typeSchema.Items.A != nil {
-			itemSchema, err = oc.getSchemaTypeFromProxy(typeSchema.Items.A, false, fieldPaths)
+		if baseSchema.Items != nil || baseSchema.Items.A != nil {
+			itemSchema, err = oc.getSchemaTypeFromProxy(baseSchema.Items.A, false, fieldPaths)
 			if err != nil {
 				return nil, err
 			}
@@ -136,7 +133,7 @@ func (oc *oas2SchemaBuilder) getSchemaType(typeSchema *base.Schema, fieldPaths [
 		}
 
 		typeResult = &SchemaInfoCache{
-			TypeSchema: createSchemaFromOpenAPISchema(typeSchema),
+			TypeSchema: createSchemaFromOpenAPISchema(baseSchema),
 			TypeRead:   schema.NewArrayType(itemSchema.TypeRead),
 			TypeWrite:  schema.NewArrayType(itemSchema.TypeWrite),
 		}
@@ -161,7 +158,7 @@ func (oc *oas2SchemaBuilder) evalObjectType(baseSchema *base.Schema, fieldPaths
 	typeResult := createSchemaFromOpenAPISchema(baseSchema)
 	refName := utils.StringSliceToPascalCase(fieldPaths)
 
-	if baseSchema.Properties == nil || baseSchema.Properties.IsZero() {
+	if baseSchema.Properties == nil || baseSchema.Properties.IsZero() || (baseSchema.AdditionalProperties != nil && (baseSchema.AdditionalProperties.B || baseSchema.AdditionalProperties.A != nil)) {
 		// treat no-property objects as a JSON scalar
 		var scalarType schema.TypeEncoder = oc.builder.buildScalarJSON()
 		if baseSchema.Nullable != nil && *baseSchema.Nullable {
diff --git a/ndc-http-schema/openapi/internal/oas3_schema.go b/ndc-http-schema/openapi/internal/oas3_schema.go
index cc569ab..2e393ed 100644
--- a/ndc-http-schema/openapi/internal/oas3_schema.go
+++ b/ndc-http-schema/openapi/internal/oas3_schema.go
@@ -86,44 +86,40 @@ func (oc *oas3SchemaBuilder) getSchemaTypeFromProxy(schemaProxy *base.SchemaProx
 }
 
 // get and convert an OpenAPI data type to a NDC type
-func (oc *oas3SchemaBuilder) getSchemaType(typeSchema *base.Schema, fieldPaths []string) (*SchemaInfoCache, error) {
-	if typeSchema == nil {
+func (oc *oas3SchemaBuilder) getSchemaType(baseSchema *base.Schema, fieldPaths []string) (*SchemaInfoCache, error) {
+	if baseSchema == nil {
 		return nil, errParameterSchemaEmpty(fieldPaths)
 	}
 
-	if oc.builder.ConvertOptions.NoDeprecation && typeSchema.Deprecated != nil && *typeSchema.Deprecated {
+	if oc.builder.ConvertOptions.NoDeprecation && baseSchema.Deprecated != nil && *baseSchema.Deprecated {
 		return nil, nil
 	}
 
-	if len(typeSchema.AllOf) > 0 {
-		return oc.buildUnionSchemaType(typeSchema, typeSchema.AllOf, oasAllOf, fieldPaths)
+	if len(baseSchema.AllOf) > 0 {
+		return oc.buildUnionSchemaType(baseSchema, baseSchema.AllOf, oasAllOf, fieldPaths)
 	}
 
-	if len(typeSchema.AnyOf) > 0 {
-		return oc.buildUnionSchemaType(typeSchema, typeSchema.AnyOf, oasAnyOf, fieldPaths)
+	if len(baseSchema.AnyOf) > 0 {
+		return oc.buildUnionSchemaType(baseSchema, baseSchema.AnyOf, oasAnyOf, fieldPaths)
 	}
 
-	if len(typeSchema.OneOf) > 0 {
-		return oc.buildUnionSchemaType(typeSchema, typeSchema.OneOf, oasOneOf, fieldPaths)
+	if len(baseSchema.OneOf) > 0 {
+		return oc.buildUnionSchemaType(baseSchema, baseSchema.OneOf, oasOneOf, fieldPaths)
 	}
 
-	oasTypes, nullable := extractNullableFromOASTypes(typeSchema.Type)
-	nullable = nullable || (typeSchema.Nullable != nil && *typeSchema.Nullable)
-	if typeSchema.AdditionalProperties != nil && (typeSchema.AdditionalProperties.B || typeSchema.AdditionalProperties.A != nil) {
-		var result schema.TypeEncoder = oc.builder.buildScalarJSON()
-		if nullable {
-			result = schema.NewNullableType(result)
+	oasTypes, nullable := extractNullableFromOASTypes(baseSchema.Type)
+	nullable = nullable || (baseSchema.Nullable != nil && *baseSchema.Nullable)
+	if len(oasTypes) == 0 {
+		// if the OAS schema has properties or items we can consider this type as an object or array
+		if baseSchema.Properties != nil && baseSchema.Properties.Len() > 0 {
+			oasTypes = []string{"object"}
+		} else if baseSchema.Items != nil && baseSchema.Items.A != nil {
+			oasTypes = []string{"array"}
 		}
-
-		return &SchemaInfoCache{
-			TypeRead:   result,
-			TypeWrite:  result,
-			TypeSchema: createSchemaFromOpenAPISchema(typeSchema),
-		}, nil
 	}
 
 	if len(oasTypes) != 1 || isPrimitiveScalar(oasTypes) {
-		scalarName := getScalarFromType(oc.builder.schema, oasTypes, typeSchema.Format, typeSchema.Enum, fieldPaths)
+		scalarName := getScalarFromType(oc.builder.schema, oasTypes, baseSchema.Format, baseSchema.Enum, fieldPaths)
 		var resultType schema.TypeEncoder = schema.NewNamedType(scalarName)
 		if nullable {
 			resultType = schema.NewNullableType(resultType)
@@ -132,7 +128,7 @@ func (oc *oas3SchemaBuilder) getSchemaType(typeSchema *base.Schema, fieldPaths [
 		return &SchemaInfoCache{
 			TypeRead:   resultType,
 			TypeWrite:  resultType,
-			TypeSchema: createSchemaFromOpenAPISchema(typeSchema),
+			TypeSchema: createSchemaFromOpenAPISchema(baseSchema),
 		}, nil
 	}
 
@@ -141,14 +137,14 @@ func (oc *oas3SchemaBuilder) getSchemaType(typeSchema *base.Schema, fieldPaths [
 	typeName := oasTypes[0]
 	switch typeName {
 	case "object":
-		typeResult, err = oc.evalObjectType(typeSchema, fieldPaths)
+		typeResult, err = oc.evalObjectType(baseSchema, fieldPaths)
 		if err != nil {
 			return nil, err
 		}
 	case "array":
 		var itemSchema *SchemaInfoCache
-		if typeSchema.Items != nil && typeSchema.Items.A != nil {
-			itemSchema, err = oc.getSchemaTypeFromProxy(typeSchema.Items.A, false, fieldPaths)
+		if baseSchema.Items != nil && baseSchema.Items.A != nil {
+			itemSchema, err = oc.getSchemaTypeFromProxy(baseSchema.Items.A, false, fieldPaths)
 			if err != nil {
 				return nil, err
 			}
@@ -162,7 +158,7 @@ func (oc *oas3SchemaBuilder) getSchemaType(typeSchema *base.Schema, fieldPaths [
 		}
 
 		typeResult = &SchemaInfoCache{
-			TypeSchema: createSchemaFromOpenAPISchema(typeSchema),
+			TypeSchema: createSchemaFromOpenAPISchema(baseSchema),
 			TypeRead:   schema.NewArrayType(itemSchema.TypeRead),
 			TypeWrite:  schema.NewArrayType(itemSchema.TypeWrite),
 		}
@@ -185,7 +181,7 @@ func (oc *oas3SchemaBuilder) getSchemaType(typeSchema *base.Schema, fieldPaths [
 func (oc *oas3SchemaBuilder) evalObjectType(baseSchema *base.Schema, fieldPaths []string) (*SchemaInfoCache, error) {
 	typeResult := createSchemaFromOpenAPISchema(baseSchema)
 	refName := utils.StringSliceToPascalCase(fieldPaths)
-	if baseSchema.Properties == nil || baseSchema.Properties.IsZero() {
+	if baseSchema.Properties == nil || baseSchema.Properties.IsZero() || (baseSchema.AdditionalProperties != nil && (baseSchema.AdditionalProperties.B || baseSchema.AdditionalProperties.A != nil)) {
 		// treat no-property objects as a JSON scalar
 		var scalarType schema.TypeEncoder = oc.builder.buildScalarJSON()
 		if baseSchema.Nullable != nil && *baseSchema.Nullable {
diff --git a/ndc-http-schema/openapi/testdata/openai/expected.json b/ndc-http-schema/openapi/testdata/openai/expected.json
index d8c61d9..0301005 100644
--- a/ndc-http-schema/openapi/testdata/openai/expected.json
+++ b/ndc-http-schema/openapi/testdata/openai/expected.json
@@ -684,8 +684,11 @@
           "type": {
             "type": "nullable",
             "underlying_type": {
-              "name": "JSON",
-              "type": "named"
+              "type": "nullable",
+              "underlying_type": {
+                "name": "JSON",
+                "type": "named"
+              }
             }
           },
           "http": {
diff --git a/ndc-http-schema/openapi/testdata/openai/schema.json b/ndc-http-schema/openapi/testdata/openai/schema.json
index b06ff63..1d9ef29 100644
--- a/ndc-http-schema/openapi/testdata/openai/schema.json
+++ b/ndc-http-schema/openapi/testdata/openai/schema.json
@@ -415,8 +415,11 @@
           "type": {
             "type": "nullable",
             "underlying_type": {
-              "name": "JSON",
-              "type": "named"
+              "type": "nullable",
+              "underlying_type": {
+                "name": "JSON",
+                "type": "named"
+              }
             }
           }
         },
diff --git a/ndc-http-schema/openapi/testdata/petstore2/swagger.json b/ndc-http-schema/openapi/testdata/petstore2/swagger.json
index 45027eb..43fd70d 100644
--- a/ndc-http-schema/openapi/testdata/petstore2/swagger.json
+++ b/ndc-http-schema/openapi/testdata/petstore2/swagger.json
@@ -169,6 +169,7 @@
             "description": "successful operation",
             "schema": {
               "type": "array",
+              "additionalProperties": true,
               "items": { "$ref": "#/definitions/Pet" }
             }
           },
diff --git a/ndc-http-schema/openapi/testdata/petstore3/expected.json b/ndc-http-schema/openapi/testdata/petstore3/expected.json
index c1b81e4..ebb8ee3 100644
--- a/ndc-http-schema/openapi/testdata/petstore3/expected.json
+++ b/ndc-http-schema/openapi/testdata/petstore3/expected.json
@@ -3287,11 +3287,7 @@
               "type": "named"
             }
           },
-          "http": {
-            "type": [
-              "object"
-            ]
-          }
+          "http": {}
         },
         "discounts": {
           "description": "The coupon or promotion code to apply to this Session. Currently, only up to one may be specified.",
diff --git a/ndc-http-schema/openapi/testdata/petstore3/source.json b/ndc-http-schema/openapi/testdata/petstore3/source.json
index 6e58e5f..6b08bc6 100644
--- a/ndc-http-schema/openapi/testdata/petstore3/source.json
+++ b/ndc-http-schema/openapi/testdata/petstore3/source.json
@@ -1557,8 +1557,7 @@
                         "x-stripeBypassValidation": true
                       }
                     },
-                    "title": "customer_update_params",
-                    "type": "object"
+                    "title": "customer_update_params"
                   },
                   "discounts": {
                     "description": "The coupon or promotion code to apply to this Session. Currently, only up to one may be specified.",
@@ -3970,6 +3969,7 @@
           },
           "tags": {
             "type": "array",
+            "additionalProperties": true,
             "xml": {
               "wrapped": true
             },
@@ -4369,7 +4369,6 @@
         "content": {
           "application/json": {
             "schema": {
-              "type": "array",
               "items": {
                 "$ref": "#/components/schemas/User"
               }