diff --git a/Cargo.toml b/Cargo.toml
index c1e8ec9..f7856b0 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -11,6 +11,7 @@ license = "MIT"
 edition = "2018"
 
 [dependencies]
+derive_builder = "0.11.2"
 failure = "0.1"
 semver = "0.11"
 serde = { version = "1.0", features = ["derive"] }
diff --git a/src/lib.rs b/src/lib.rs
index e0fa23f..aeb6776 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -27,6 +27,9 @@
 use serde::{Deserialize, Serialize};
 use std::{fs::File, io::Read, path::Path, result::Result as StdResult};
 
+#[macro_use]
+extern crate derive_builder;
+
 pub mod error;
 pub mod v2;
 pub mod v3_0;
diff --git a/src/v2/schema.rs b/src/v2/schema.rs
index 374b19c..c3e0265 100644
--- a/src/v2/schema.rs
+++ b/src/v2/schema.rs
@@ -19,8 +19,9 @@ impl Default for Scheme {
 }
 
 /// top level document
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
 #[serde(rename_all = "camelCase")]
+#[builder(setter(into, strip_option), default)]
 pub struct Spec {
     /// The Swagger version of this document.
     pub swagger: String,
@@ -61,8 +62,9 @@ pub struct Spec {
     pub external_docs: Option<Vec<ExternalDoc>>,
 }
 
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
 #[serde(rename_all = "lowercase")]
+#[builder(setter(into, strip_option), default)]
 pub struct Tag {
     pub name: String,
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -71,7 +73,8 @@ pub struct Tag {
     pub external_docs: Option<Vec<ExternalDoc>>,
 }
 
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 pub struct ExternalDoc {
     pub url: String,
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -81,8 +84,9 @@ pub struct ExternalDoc {
 /// General information about the API.
 ///
 /// https://github.com/OAI/OpenAPI-Specification/blob/master/versions/2.0.md#info-object
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
 #[serde(rename_all = "lowercase")]
+#[builder(setter(into, strip_option), default)]
 pub struct Info {
     /// A unique and precise title of the API.
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -100,7 +104,8 @@ pub struct Info {
     pub version: Option<String>,
 }
 
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 pub struct Contact {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub name: Option<String>,
@@ -113,7 +118,8 @@ pub struct Contact {
 }
 
 /// todo x-* properties
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 pub struct License {
     /// The name of the license type. It's encouraged to use an OSI
     /// compatible license.
@@ -126,7 +132,8 @@ pub struct License {
 }
 
 /// todo support x-* properties
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 pub struct PathItem {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub get: Option<Operation>,
@@ -147,7 +154,8 @@ pub struct PathItem {
 }
 
 /// https://github.com/OAI/OpenAPI-Specification/blob/master/versions/2.0.md#operation-object
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 #[serde(rename_all = "lowercase")]
 pub struct Operation {
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -174,7 +182,8 @@ pub struct Operation {
 /// https://github.com/OAI/OpenAPI-Specification/blob/master/versions/2.0.md#securityRequirementObject
 pub type SecurityRequirement = BTreeMap<String, Vec<String>>;
 
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 #[serde(rename_all = "camelCase")]
 pub struct Parameter {
     pub name: String,
@@ -199,7 +208,8 @@ pub struct Parameter {
     default: Option<serde_json::Value>,
 }
 
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 pub struct Response {
     pub description: String,
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -308,7 +318,8 @@ pub enum Flow {
 /// the shape and properties of an object.
 ///
 /// This may also contain a `$ref` to another definition
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 pub struct Schema {
     #[serde(skip_serializing_if = "Option::is_none")]
     /// [JSON reference](https://tools.ietf.org/html/draft-pbryan-zyp-json-ref-03)
diff --git a/src/v3_0/components.rs b/src/v3_0/components.rs
index 45a93d3..a722b7c 100644
--- a/src/v3_0/components.rs
+++ b/src/v3_0/components.rs
@@ -15,6 +15,12 @@ pub enum ObjectOrReference<T> {
     },
 }
 
+pub trait OrReference {
+    fn or_ref(self) -> ObjectOrReference<Self> where Self: Sized {
+        ObjectOrReference::Object(self)
+    }
+}
+
 #[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
 #[serde(untagged)]
 pub enum BooleanObjectOrReference<T> {
@@ -32,7 +38,8 @@ pub enum BooleanObjectOrReference<T> {
 /// they are explicitly referenced from properties outside the components object.
 ///
 /// See <https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.1.md#componentsObject>.
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 pub struct Components {
     /// An object to hold reusable Schema Objects.
     #[serde(skip_serializing_if = "Option::is_none")]
diff --git a/src/v3_0/schema.rs b/src/v3_0/schema.rs
index ab8ba7d..08a97ea 100644
--- a/src/v3_0/schema.rs
+++ b/src/v3_0/schema.rs
@@ -1,6 +1,7 @@
 //! Schema specification for [OpenAPI 3.0.0](https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.0.md)
 
 use crate::v3_0::extension::Extensions;
+use crate::v3_0::components::OrReference;
 use serde::{Deserialize, Serialize};
 use std::collections::{BTreeMap, HashMap};
 use url::Url;
@@ -24,7 +25,8 @@ impl Spec {
 }
 
 /// top level document
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 pub struct Spec {
     /// This string MUST be the [semantic version number](https://semver.org/spec/v2.0.0.html)
     /// of the
@@ -86,7 +88,8 @@ pub struct Spec {
 ///
 ///
 /// See <https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.1.md#infoObject>.
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 // #[serde(rename_all = "lowercase")]
 pub struct Info {
     /// The title of the application.
@@ -112,7 +115,8 @@ pub struct Info {
 /// Contact information for the exposed API.
 ///
 /// See <https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.1.md#contactObject>.
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 pub struct Contact {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub name: Option<String>,
@@ -130,7 +134,8 @@ pub struct Contact {
 /// License information for the exposed API.
 ///
 /// See <https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.1.md#licenseObject>.
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 pub struct License {
     /// The license name used for the API.
     pub name: String,
@@ -144,7 +149,8 @@ pub struct License {
 /// An object representing a Server.
 ///
 /// See <https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.1.md#serverObject>.
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 pub struct Server {
     /// A URL to the target host. This URL supports Server Variables and MAY be relative, to
     /// indicate that the host location is relative to the location where the OpenAPI document
@@ -163,7 +169,8 @@ pub struct Server {
 /// An object representing a Server Variable for server URL template substitution.
 ///
 /// See <https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.1.md#serverVariableObject>.
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 pub struct ServerVariable {
     /// The default value to use for substitution, and to send, if an alternate value is not
     /// supplied. Unlike the Schema Object's default, this value MUST be provided by the consumer.
@@ -186,7 +193,8 @@ pub struct ServerVariable {
 /// constraints](https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.1.md#securityFiltering).
 /// The path itself is still exposed to the documentation viewer but they will not know which
 /// operations and parameters are available.
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 pub struct PathItem {
     /// Allows for an external definition of this path item. The referenced structure MUST be
     /// in the format of a
@@ -253,7 +261,8 @@ pub struct PathItem {
 /// Describes a single API operation on a path.
 ///
 /// See <https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.1.md#operationObject>.
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 // #[serde(rename_all = "lowercase")]
 pub struct Operation {
     /// A list of tags for API documentation control. Tags can be used for logical grouping of
@@ -352,7 +361,8 @@ pub struct Operation {
 /// and [location](https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.1.md#parameterIn).
 ///
 /// See <https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.1.md#parameterObject>.
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 pub struct Parameter {
     /// The name of the parameter.
     pub name: String,
@@ -398,9 +408,11 @@ pub struct Parameter {
     style: Option<ParameterStyle>,
 }
 
+impl OrReference for Parameter {}
+
 #[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
 #[serde(rename_all = "camelCase")]
-enum ParameterStyle {
+pub enum ParameterStyle {
     Matrix,
     Label,
     Form,
@@ -421,7 +433,8 @@ enum ParameterStyle {
 /// Unless stated otherwise, the property definitions follow the JSON Schema.
 ///
 /// See <https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.1.md#schemaObject>.
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 pub struct Schema {
     /// [JSON reference](https://tools.ietf.org/html/draft-pbryan-zyp-json-ref-03)
     /// path to another definition
@@ -540,8 +553,11 @@ pub struct Schema {
     /// of the schema if one is not provided. Unlike JSON Schema, the value MUST conform to the
     /// defined type for the Schema Object defined at the same level. For example, if type is
     /// `string`, then `default` can be `"foo"` but cannot be `1`.
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub default: Option<serde_json::Value>,
+    #[serde(
+        skip_serializing_if = "Option::is_none",
+        rename = "default"
+    )]
+    pub default_value: Option<serde_json::Value>,
 
     /// Inline or referenced schema MUST be of a [Schema Object](#schemaObject) and not a standard
     /// JSON Schema.
@@ -572,11 +588,14 @@ pub struct Schema {
     pub extensions: HashMap<String, String>,
 }
 
+impl OrReference for Schema {}
+
 /// Describes a single response from an API Operation, including design-time, static `links`
 /// to operations based on the response.
 ///
 /// See <https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.1.md#responseObject>.
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 pub struct Response {
     /// A short description of the response.
     /// [CommonMark syntax](http://spec.commonmark.org/) MAY be used for rich text representation.
@@ -614,7 +633,8 @@ pub struct Response {
 ///    `header` (for example, [`style`](https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.1.md#parameterStyle)).
 ///
 /// See <https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.1.md#headerObject>.
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 pub struct Header {
     // FIXME: Is the third change properly implemented?
     // FIXME: Merge `ObjectOrReference<Header>::Reference` and `ParameterOrRef::Reference`
@@ -654,7 +674,8 @@ pub struct Header {
 /// Describes a single request body.
 ///
 /// See <https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.1.md#requestBodyObject>.
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 pub struct RequestBody {
     /// A brief description of the request body. This could contain examples of use.
     /// [CommonMark syntax](http://spec.commonmark.org/) MAY be used for rich text representation.
@@ -671,6 +692,8 @@ pub struct RequestBody {
     pub required: Option<bool>,
 }
 
+impl OrReference for RequestBody {}
+
 /// The Link object represents a possible design-time link for a response.
 ///
 /// The presence of a link does not guarantee the caller's ability to successfully invoke it,
@@ -768,7 +791,8 @@ pub enum Link {
 /// Each Media Type Object provides schema and examples for the media type identified by its key.
 ///
 /// See <https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.1.md#media-type-object>.
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 pub struct MediaType {
     /// The schema defining the type used for the request body.
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -804,7 +828,8 @@ pub enum MediaTypeExample {
 }
 
 /// A single encoding definition applied to a single schema property.
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 pub struct Encoding {
     /// The Content-Type for encoding a specific property. Default value depends on the
     /// property type: for `string` with `format` being `binary` – `application/octet-stream`;
@@ -852,7 +877,8 @@ pub struct Encoding {
 }
 
 /// See <https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.1.md#exampleObject>.
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 pub struct Example {
     /// Short description for the example.
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -1000,7 +1026,8 @@ pub struct Callback(
 /// It is not mandatory to have a Tag Object per tag defined in the Operation Object instances.
 ///
 /// See <https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.1.md#tagObject>.
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default)]
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Default, Builder)]
+#[builder(setter(into, strip_option), default)]
 pub struct Tag {
     /// The name of the tag.
     pub name: String,