diff --git a/package.json b/package.json
index 789991d..4c3c032 100644
--- a/package.json
+++ b/package.json
@@ -52,13 +52,11 @@
     "graphql": "^16.0.0",
     "inflection": "^3.0.0",
     "jsonld": "^8.3.2",
-    "jsonref": "^9.0.0",
-    "lodash.get": "^4.4.0"
+    "jsonref": "^9.0.0"
   },
   "devDependencies": {
     "@types/inflection": "^1.13.0",
     "@types/jsonld": "^1.5.0",
-    "@types/lodash.get": "^4.4.0",
     "@types/node": "^22.0.0",
     "@vitest/coverage-v8": "3.2.2",
     "globals": "^15.14.0",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 0e02052..f8000f5 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -20,9 +20,6 @@ importers:
       jsonref:
         specifier: ^9.0.0
         version: 9.0.0
-      lodash.get:
-        specifier: ^4.4.0
-        version: 4.4.2
     devDependencies:
       '@types/inflection':
         specifier: ^1.13.0
@@ -30,9 +27,6 @@ importers:
       '@types/jsonld':
         specifier: ^1.5.0
         version: 1.5.15
-      '@types/lodash.get':
-        specifier: ^4.4.0
-        version: 4.4.9
       '@types/node':
         specifier: ^22.0.0
         version: 22.15.29
@@ -487,12 +481,6 @@ packages:
   '@types/jsonld@1.5.15':
     resolution: {integrity: sha512-PlAFPZjL+AuGYmwlqwKEL0IMP8M8RexH0NIPGfCVWSQ041H2rR/8OlyZSD7KsCVoN8vCfWdtWDBxX8yBVP+xow==}
 
-  '@types/lodash.get@4.4.9':
-    resolution: {integrity: sha512-J5dvW98sxmGnamqf+/aLP87PYXyrha9xIgc2ZlHl6OHMFR2Ejdxep50QfU0abO1+CH6+ugx+8wEUN1toImAinA==}
-
-  '@types/lodash@4.17.17':
-    resolution: {integrity: sha512-RRVJ+J3J+WmyOTqnz3PiBLA501eKwXl2noseKOrNo/6+XEHjTAxO4xHvxQB6QuNm+s4WRbn6rSiap8+EA+ykFQ==}
-
   '@types/node@22.15.29':
     resolution: {integrity: sha512-LNdjOkUDlU1RZb8e1kOIUpN1qQUlzGkEtbVNo53vbrwDg5om6oduhm4SiUaPW5ASTXhAiP0jInWG8Qx9fVlOeQ==}
 
@@ -773,10 +761,6 @@ packages:
     resolution: {integrity: sha512-CasD9OCEQSFIam2U8efFK81Yeg8vNMTBUqtMOHlrcWQHqUX3HeCl9Dr31u4toV7emlH8Mymk5+9p0lL6mKb/Xw==}
     engines: {node: '>=14.16'}
 
-  lodash.get@4.4.2:
-    resolution: {integrity: sha512-z+Uw/vLuy6gQe8cfaFWD7p0wVv8fJl3mbzXh33RS+0oW2wvUqiRXiQ69gLWSLpgB5/6sU+r6BlQR0MBILadqTQ==}
-    deprecated: This package is deprecated. Use the optional chaining (?.) operator instead.
-
   loupe@3.1.3:
     resolution: {integrity: sha512-kkIp7XSkP78ZxJEsSxW3712C6teJVoeHHwgo9zJ380de7IYyJ2ISlxojcH2pC5OFLewESmnRi/+XCDIEEVyoug==}
 
@@ -1438,12 +1422,6 @@ snapshots:
 
   '@types/jsonld@1.5.15': {}
 
-  '@types/lodash.get@4.4.9':
-    dependencies:
-      '@types/lodash': 4.17.17
-
-  '@types/lodash@4.17.17': {}
-
   '@types/node@22.15.29':
     dependencies:
       undici-types: 6.21.0
@@ -1735,8 +1713,6 @@ snapshots:
 
   ky@0.33.3: {}
 
-  lodash.get@4.4.2: {}
-
   loupe@3.1.3: {}
 
   lru-cache@10.4.3: {}
diff --git a/src/hydra/fetchJsonLd.ts b/src/hydra/fetchJsonLd.ts
index d972dcf..90b453d 100644
--- a/src/hydra/fetchJsonLd.ts
+++ b/src/hydra/fetchJsonLd.ts
@@ -1,5 +1,5 @@
 import type { Document, JsonLd, RemoteDocument } from "jsonld/jsonld-spec.js";
-import type { RequestInitExtended } from "./types.js";
+import type { RequestInitExtended } from "../types.js";
 
 const jsonLdMimeType = "application/ld+json";
 const jsonProblemMimeType = "application/problem+json";
diff --git a/src/hydra/fetchResource.ts b/src/hydra/fetchResource.ts
index ba23a8c..edf0d8c 100644
--- a/src/hydra/fetchResource.ts
+++ b/src/hydra/fetchResource.ts
@@ -1,5 +1,6 @@
 import fetchJsonLd from "./fetchJsonLd.js";
-import type { IriTemplateMapping, RequestInitExtended } from "./types.js";
+import type { IriTemplateMapping } from "./types.js";
+import type { RequestInitExtended } from "../types.js";
 
 export default async function fetchResource(
   resourceUrl: string,
diff --git a/src/hydra/getParameters.ts b/src/hydra/getParameters.ts
index 35e8d68..eee599c 100644
--- a/src/hydra/getParameters.ts
+++ b/src/hydra/getParameters.ts
@@ -1,7 +1,7 @@
 import { Parameter } from "../Parameter.js";
 import fetchResource from "./fetchResource.js";
 import type { Resource } from "../Resource.js";
-import type { RequestInitExtended } from "./types.js";
+import type { RequestInitExtended } from "../types.js";
 
 export default async function getParameters(
   resource: Resource,
diff --git a/src/hydra/parseHydraDocumentation.ts b/src/hydra/parseHydraDocumentation.ts
index c7f4dc3..321097d 100644
--- a/src/hydra/parseHydraDocumentation.ts
+++ b/src/hydra/parseHydraDocumentation.ts
@@ -1,5 +1,4 @@
 import jsonld from "jsonld";
-import get from "lodash.get";
 import { Api } from "../Api.js";
 import { Field } from "../Field.js";
 import { Resource } from "../Resource.js";
@@ -15,8 +14,8 @@ import type {
   Entrypoint,
   ExpandedOperation,
   ExpandedRdfProperty,
-  RequestInitExtended,
 } from "./types.js";
+import type { RequestInitExtended } from "../types.js";
 
 /**
  * Extracts the short name of a resource.
@@ -45,10 +44,8 @@ function findSupportedClass(
   docs: ExpandedDoc[],
   classToFind: string,
 ): ExpandedClass {
-  const supportedClasses = get(
-    docs,
-    '[0]["http://www.w3.org/ns/hydra/core#supportedClass"]',
-  ) as ExpandedClass[] | undefined;
+  const supportedClasses =
+    docs?.[0]?.["http://www.w3.org/ns/hydra/core#supportedClass"];
   if (!Array.isArray(supportedClasses)) {
     throw new TypeError(
       'The API documentation has no "http://www.w3.org/ns/hydra/core#supportedClass" key or its value is not an array.',
@@ -155,7 +152,7 @@ async function fetchEntrypointAndDocs(
       api: new Api(entrypointUrl, { resources: [] }),
       error,
       response,
-      status: get(response, "status"),
+      status: response?.status,
     };
   }
 }
@@ -173,25 +170,30 @@ function findRelatedClass(
   property: ExpandedRdfProperty,
 ): ExpandedClass {
   // Use the entrypoint property's owl:equivalentClass if available
-  if (Array.isArray(property["http://www.w3.org/2000/01/rdf-schema#range"])) {
-    for (const range of property[
-      "http://www.w3.org/2000/01/rdf-schema#range"
-    ]) {
-      const onProperty = get(
-        range,
-        '["http://www.w3.org/2002/07/owl#equivalentClass"][0]["http://www.w3.org/2002/07/owl#onProperty"][0]["@id"]',
-      ) as unknown as string;
-      const allValuesFrom = get(
-        range,
-        '["http://www.w3.org/2002/07/owl#equivalentClass"][0]["http://www.w3.org/2002/07/owl#allValuesFrom"][0]["@id"]',
-      ) as unknown as string;
 
-      if (
-        allValuesFrom &&
-        onProperty === "http://www.w3.org/ns/hydra/core#member"
-      ) {
-        return findSupportedClass(docs, allValuesFrom);
-      }
+  for (const range of property["http://www.w3.org/2000/01/rdf-schema#range"] ??
+    []) {
+    const equivalentClass =
+      "http://www.w3.org/2002/07/owl#equivalentClass" in range
+        ? range?.["http://www.w3.org/2002/07/owl#equivalentClass"]?.[0]
+        : undefined;
+
+    if (!equivalentClass) {
+      continue;
+    }
+
+    const onProperty =
+      equivalentClass["http://www.w3.org/2002/07/owl#onProperty"]?.[0]?.["@id"];
+    const allValuesFrom =
+      equivalentClass["http://www.w3.org/2002/07/owl#allValuesFrom"]?.[0]?.[
+        "@id"
+      ];
+
+    if (
+      allValuesFrom &&
+      onProperty === "http://www.w3.org/ns/hydra/core#member"
+    ) {
+      return findSupportedClass(docs, allValuesFrom);
     }
   }
 
@@ -205,10 +207,10 @@ function findRelatedClass(
       continue;
     }
 
-    const returns = get(
-      entrypointSupportedOperation,
-      '["http://www.w3.org/ns/hydra/core#returns"][0]["@id"]',
-    ) as string | undefined;
+    const returns =
+      entrypointSupportedOperation?.[
+        "http://www.w3.org/ns/hydra/core#returns"
+      ]?.[0]?.["@id"];
     if (
       typeof returns === "string" &&
       returns.indexOf("http://www.w3.org/ns/hydra/core") !== 0
@@ -241,15 +243,11 @@ export default async function parseHydraDocumentation(
   const resources = [],
     fields = [],
     operations = [];
-  const title = get(
-    docs,
-    '[0]["http://www.w3.org/ns/hydra/core#title"][0]["@value"]',
-    "API Platform",
-  ) as string;
-
-  const entrypointType = get(entrypoint, '[0]["@type"][0]') as
-    | string
-    | undefined;
+  const title =
+    docs?.[0]?.["http://www.w3.org/ns/hydra/core#title"]?.[0]?.["@value"] ??
+    "API Platform";
+
+  const entrypointType = entrypoint?.[0]?.["@type"]?.[0];
   if (!entrypointType) {
     throw new Error('The API entrypoint has no "@type" key.');
   }
@@ -274,23 +272,25 @@ export default async function parseHydraDocumentation(
       writableFields = [],
       resourceOperations = [];
 
-    const property = get(
-      properties,
-      '["http://www.w3.org/ns/hydra/core#property"][0]',
-    ) as ExpandedRdfProperty | undefined;
+    const property =
+      properties?.["http://www.w3.org/ns/hydra/core#property"]?.[0];
+    const propertyIri = property?.["@id"];
 
-    if (!property) {
+    if (!property || !propertyIri) {
       continue;
     }
 
-    const url = get(entrypoint, `[0]["${property["@id"]}"][0]["@id"]`) as
-      | string
-      | undefined;
+    const resourceProperty = entrypoint?.[0]?.[propertyIri]?.[0];
+
+    const url =
+      typeof resourceProperty === "object"
+        ? resourceProperty["@id"]
+        : undefined;
 
     if (!url) {
       console.error(
         new Error(
-          `Unable to find the URL for "${property["@id"]}" in the entrypoint, make sure your API resource has at least one GET collection operation declared.`,
+          `Unable to find the URL for "${propertyIri}" in the entrypoint, make sure your API resource has at least one GET collection operation declared.`,
         ),
       );
       continue;
@@ -298,19 +298,16 @@ export default async function parseHydraDocumentation(
 
     // Add fields
     const relatedClass = findRelatedClass(docs, property);
-    for (const supportedProperties of relatedClass[
+    for (const supportedProperties of relatedClass?.[
       "http://www.w3.org/ns/hydra/core#supportedProperty"
-    ]) {
-      const supportedProperty = get(
-        supportedProperties,
-        '["http://www.w3.org/ns/hydra/core#property"][0]',
-      ) as unknown as ExpandedRdfProperty;
+    ] ?? []) {
+      const supportedProperty =
+        supportedProperties?.["http://www.w3.org/ns/hydra/core#property"]?.[0];
       const id = supportedProperty?.["@id"];
-      const range = get(
-        supportedProperty,
-        '["http://www.w3.org/2000/01/rdf-schema#range"][0]["@id"]',
-        null,
-      ) as unknown as string;
+      const range =
+        supportedProperty?.[
+          "http://www.w3.org/2000/01/rdf-schema#range"
+        ]?.[0]?.["@id"] ?? null;
 
       const field = new Field(
         supportedProperties?.["http://www.w3.org/ns/hydra/core#title"]?.[0]?.[
@@ -324,35 +321,31 @@ export default async function parseHydraDocumentation(
           range,
           type: getType(id, range),
           reference:
-            get(supportedProperty, '["@type"][0]') ===
+            supportedProperty?.["@type"]?.[0] ===
             "http://www.w3.org/ns/hydra/core#Link"
               ? range // Will be updated in a subsequent pass
               : null,
           embedded:
-            get(supportedProperty, '["@type"][0]') ===
+            supportedProperty?.["@type"]?.[0] ===
             "http://www.w3.org/ns/hydra/core#Link"
               ? null
               : (range as unknown as Resource), // Will be updated in a subsequent pass
-          required: get(
-            supportedProperties,
-            '["http://www.w3.org/ns/hydra/core#required"][0]["@value"]',
-            false,
-          ) as boolean,
-          description: get(
-            supportedProperties,
-            '["http://www.w3.org/ns/hydra/core#description"][0]["@value"]',
-            "",
-          ) as string,
-          maxCardinality: get(
-            supportedProperty,
-            '["http://www.w3.org/2002/07/owl#maxCardinality"][0]["@value"]',
-            null,
-          ) as number | null,
-          deprecated: get(
-            supportedProperties,
-            '["http://www.w3.org/2002/07/owl#deprecated"][0]["@value"]',
-            false,
-          ) as boolean,
+          required:
+            supportedProperties?.[
+              "http://www.w3.org/ns/hydra/core#required"
+            ]?.[0]?.["@value"] ?? false,
+          description:
+            supportedProperties?.[
+              "http://www.w3.org/ns/hydra/core#description"
+            ]?.[0]?.["@value"] ?? "",
+          maxCardinality:
+            supportedProperty?.[
+              "http://www.w3.org/2002/07/owl#maxCardinality"
+            ]?.[0]?.["@value"] ?? null,
+          deprecated:
+            supportedProperties?.[
+              "http://www.w3.org/2002/07/owl#deprecated"
+            ]?.[0]?.["@value"] ?? false,
         },
       );
 
@@ -360,23 +353,20 @@ export default async function parseHydraDocumentation(
       resourceFields.push(field);
 
       if (
-        get(
-          supportedProperties,
-          '["http://www.w3.org/ns/hydra/core#readable"][0]["@value"]',
-        )
+        supportedProperties?.[
+          "http://www.w3.org/ns/hydra/core#readable"
+        ]?.[0]?.["@value"]
       ) {
         readableFields.push(field);
       }
 
       if (
-        get(
-          supportedProperties,
-          '["http://www.w3.org/ns/hydra/core#writeable"][0]["@value"]',
-        ) ||
-        get(
-          supportedProperties,
-          '["http://www.w3.org/ns/hydra/core#writable"][0]["@value"]',
-        )
+        supportedProperties?.[
+          "http://www.w3.org/ns/hydra/core#writeable"
+        ]?.[0]?.["@value"] ||
+        supportedProperties?.[
+          "http://www.w3.org/ns/hydra/core#writable"
+        ]?.[0]?.["@value"]
       ) {
         writableFields.push(field);
       }
@@ -414,11 +404,10 @@ export default async function parseHydraDocumentation(
               ]?.[0]?.["@id"],
             returns: range,
             types: entrypointOperation["@type"],
-            deprecated: get(
-              entrypointOperation,
-              '["http://www.w3.org/2002/07/owl#deprecated"][0]["@value"]',
-              false,
-            ) as boolean,
+            deprecated:
+              entrypointOperation?.[
+                "http://www.w3.org/2002/07/owl#deprecated"
+              ]?.[0]?.["@value"] ?? false,
           },
         );
 
@@ -464,11 +453,10 @@ export default async function parseHydraDocumentation(
             ]?.[0]?.["@id"],
           returns: range,
           types: supportedOperation["@type"],
-          deprecated: get(
-            supportedOperation,
-            '["http://www.w3.org/2002/07/owl#deprecated"][0]["@value"]',
-            false,
-          ) as boolean,
+          deprecated:
+            supportedOperation?.[
+              "http://www.w3.org/2002/07/owl#deprecated"
+            ]?.[0]?.["@value"] ?? false,
         },
       );
 
@@ -478,20 +466,18 @@ export default async function parseHydraDocumentation(
 
     const resource = new Resource(guessNameFromUrl(url, entrypointUrl), url, {
       id: relatedClass["@id"],
-      title: get(
-        relatedClass,
-        '["http://www.w3.org/ns/hydra/core#title"][0]["@value"]',
-        "",
-      ) as string,
+      title:
+        relatedClass?.["http://www.w3.org/ns/hydra/core#title"]?.[0]?.[
+          "@value"
+        ] ?? "",
       fields: resourceFields,
       readableFields,
       writableFields,
       operations: resourceOperations,
-      deprecated: get(
-        relatedClass,
-        '["http://www.w3.org/2002/07/owl#deprecated"][0]["@value"]',
-        false,
-      ) as boolean,
+      deprecated:
+        relatedClass?.["http://www.w3.org/2002/07/owl#deprecated"]?.[0]?.[
+          "@value"
+        ] ?? false,
     });
 
     resource.parameters = [];
diff --git a/src/hydra/types.ts b/src/hydra/types.ts
index 6bba55f..41150a8 100644
--- a/src/hydra/types.ts
+++ b/src/hydra/types.ts
@@ -1,7 +1,3 @@
-export interface RequestInitExtended extends Omit<RequestInit, "headers"> {
-  headers?: HeadersInit | (() => HeadersInit);
-}
-
 export interface IriTemplateMapping {
   "@type": "IriTemplateMapping";
   variable: "string";
diff --git a/src/openapi3/dereferencedOpenApiv3.ts b/src/openapi3/dereferencedOpenApiv3.ts
new file mode 100644
index 0000000..e0cd32a
--- /dev/null
+++ b/src/openapi3/dereferencedOpenApiv3.ts
@@ -0,0 +1,156 @@
+// oxlint-disable consistent-indexed-object-style
+import type { OpenAPIV3 } from "openapi-types";
+
+interface ArraySchemaObjectDereferenced extends BaseSchemaObjectDereferenced {
+  type: OpenAPIV3.ArraySchemaObjectType;
+  items: SchemaObjectDereferenced;
+}
+
+interface NonArraySchemaObjectDereferenced
+  extends BaseSchemaObjectDereferenced {
+  type?: OpenAPIV3.NonArraySchemaObjectType;
+}
+
+export type SchemaObjectDereferenced =
+  | ArraySchemaObjectDereferenced
+  | NonArraySchemaObjectDereferenced;
+
+type BaseSchemaObjectDereferenced = Omit<
+  OpenAPIV3.BaseSchemaObject,
+  "additionalProperties" | "properties" | "allOf" | "oneOf" | "anyOf" | "not"
+> & {
+  additionalProperties?: boolean | SchemaObjectDereferenced;
+  properties?: {
+    [name: string]: SchemaObjectDereferenced;
+  };
+  allOf?: SchemaObjectDereferenced[];
+  oneOf?: SchemaObjectDereferenced[];
+  anyOf?: SchemaObjectDereferenced[];
+  not?: SchemaObjectDereferenced;
+};
+
+type EncodingObjectDereferenced = Omit<OpenAPIV3.EncodingObject, "headers"> & {
+  headers?: {
+    [header: string]: HeaderObjectDereferenced;
+  };
+};
+
+type MediaTypeObjectDereferenced = Omit<
+  OpenAPIV3.MediaTypeObject,
+  "schema" | "encoding"
+> & {
+  schema?: SchemaObjectDereferenced;
+  encoding?: {
+    [media: string]: EncodingObjectDereferenced;
+  };
+};
+
+type ParameterBaseObjectDereferenced = Omit<
+  OpenAPIV3.ParameterObject,
+  "schema" | "content"
+> & {
+  schema?: SchemaObjectDereferenced;
+  content?: {
+    [media: string]: MediaTypeObjectDereferenced;
+  };
+};
+
+interface HeaderObjectDereferenced extends ParameterBaseObjectDereferenced {}
+
+type RequestBodyObjectDereferenced = Omit<
+  OpenAPIV3.RequestBodyObject,
+  "content"
+> & {
+  content: {
+    [media: string]: MediaTypeObjectDereferenced;
+  };
+};
+
+type ResponseObjectDereferenced = Omit<
+  OpenAPIV3.ResponseObject,
+  "headers" | "content"
+> & {
+  headers?: {
+    [header: string]: HeaderObjectDereferenced;
+  };
+  content?: {
+    [media: string]: MediaTypeObjectDereferenced;
+  };
+};
+
+interface ResponsesObjectDereferenced {
+  [code: string]: ResponseObjectDereferenced;
+}
+
+interface ParameterObjectDereferenced extends ParameterBaseObjectDereferenced {
+  name: string;
+  in: string;
+}
+
+type PathItemObjectDereferenced<T extends object = object> = Omit<
+  OpenAPIV3.PathItemObject,
+  "parameters" | `${OpenAPIV3.HttpMethods}`
+> & {
+  parameters?: ParameterObjectDereferenced[];
+} & {
+  [method in OpenAPIV3.HttpMethods]?: OperationObjectDereferenced<T>;
+};
+interface CallbackObjectDereferenced {
+  [url: string]: PathItemObjectDereferenced;
+}
+
+export type OperationObjectDereferenced<T extends object = object> = Omit<
+  OpenAPIV3.OperationObject,
+  "parameters" | "requestBody" | "responses" | "callbacks"
+> & {
+  parameters?: ParameterObjectDereferenced[];
+  requestBody?: RequestBodyObjectDereferenced;
+  responses: ResponsesObjectDereferenced;
+  callbacks?: {
+    [callback: string]: CallbackObjectDereferenced;
+  };
+} & T;
+
+interface PathsObjectDereferenced<
+  T extends object = object,
+  P extends object = object,
+> {
+  [pattern: string]: (PathItemObjectDereferenced<T> & P) | undefined;
+}
+
+type ComponentsObjectDereferenced = Omit<
+  OpenAPIV3.ComponentsObject,
+  | "schemas"
+  | "responses"
+  | "parameters"
+  | "requestBodies"
+  | "headers"
+  | "callbacks"
+> & {
+  schemas?: {
+    [key: string]: SchemaObjectDereferenced;
+  };
+  responses?: {
+    [key: string]: ResponseObjectDereferenced;
+  };
+  parameters?: {
+    [key: string]: ParameterObjectDereferenced;
+  };
+  requestBodies?: {
+    [key: string]: RequestBodyObjectDereferenced;
+  };
+  headers?: {
+    [key: string]: HeaderObjectDereferenced;
+  };
+  callbacks?: {
+    [key: string]: CallbackObjectDereferenced;
+  };
+};
+
+export type OpenAPIV3DocumentDereferenced<T extends object = object> = Omit<
+  OpenAPIV3.Document,
+  "paths" | "components"
+> & {
+  paths: PathsObjectDereferenced<T>;
+  components?: ComponentsObjectDereferenced;
+};
diff --git a/src/openapi3/handleJson.ts b/src/openapi3/handleJson.ts
index 2dfdcbc..388f45b 100644
--- a/src/openapi3/handleJson.ts
+++ b/src/openapi3/handleJson.ts
@@ -1,34 +1,23 @@
-import { parse as dereference } from "jsonref";
-import get from "lodash.get";
 import inflection from "inflection";
+import type { ParseOptions } from "jsonref";
+import { parse } from "jsonref";
+import type { OpenAPIV3 } from "openapi-types";
 import { Field } from "../Field.js";
+import type { OperationType } from "../Operation.js";
 import { Operation } from "../Operation.js";
 import { Parameter } from "../Parameter.js";
 import { Resource } from "../Resource.js";
 import getResourcePaths from "../utils/getResources.js";
+import type {
+  OpenAPIV3DocumentDereferenced,
+  OperationObjectDereferenced,
+  SchemaObjectDereferenced,
+} from "./dereferencedOpenApiv3.js";
 import getType from "./getType.js";
-import type { OpenAPIV3 } from "openapi-types";
-import type { OperationType } from "../Operation.js";
-
-function isParameter(
-  maybeParameter: OpenAPIV3.ReferenceObject | OpenAPIV3.ParameterObject,
-): maybeParameter is OpenAPIV3.ParameterObject {
-  return (
-    maybeParameter !== undefined &&
-    "name" in maybeParameter &&
-    "in" in maybeParameter
-  );
-}
-
-function isSchema(
-  maybeSchema: OpenAPIV3.SchemaObject | OpenAPIV3.ReferenceObject | undefined,
-): maybeSchema is OpenAPIV3.SchemaObject {
-  return maybeSchema !== undefined && !("$ref" in maybeSchema);
-}
 
 export function removeTrailingSlash(url: string): string {
   if (url.endsWith("/")) {
-    url = url.slice(0, -1);
+    return url.slice(0, -1);
   }
   return url;
 }
@@ -57,45 +46,47 @@ function mergeResources(resourceA: Resource, resourceB: Resource) {
   return resourceA;
 }
 
+function buildEnumObject(enumArray: SchemaObjectDereferenced["enum"]) {
+  if (!enumArray) {
+    return null;
+  }
+  return Object.fromEntries(
+    // Object.values is used because the array is annotated: it contains the __meta symbol used by jsonref.
+    Object.values(enumArray).map((enumValue) => [
+      typeof enumValue === "string"
+        ? inflection.humanize(enumValue)
+        : enumValue,
+      enumValue,
+    ]),
+  );
+}
+
+function getArrayType(property: SchemaObjectDereferenced) {
+  if (property.type !== "array") {
+    return null;
+  }
+  return getType(property.items.type || "string", property.items.format);
+}
+
 function buildResourceFromSchema(
-  schema: OpenAPIV3.SchemaObject,
+  schema: SchemaObjectDereferenced,
   name: string,
   title: string,
   url: string,
 ) {
   const { description = "", properties = {} } = schema;
-  const fieldNames = Object.keys(properties);
   const requiredFields = schema.required || [];
-
+  const fields: Field[] = [];
   const readableFields: Field[] = [];
   const writableFields: Field[] = [];
 
-  const fields = fieldNames.map((fieldName) => {
-    const property = properties[fieldName] as OpenAPIV3.SchemaObject;
-
-    const type = getType(property.type || "string", property.format);
+  for (const [fieldName, property] of Object.entries(properties)) {
     const field = new Field(fieldName, {
       id: null,
       range: null,
-      type,
-      arrayType:
-        type === "array" && "items" in property
-          ? getType(
-              (property.items as OpenAPIV3.SchemaObject).type || "string",
-              (property.items as OpenAPIV3.SchemaObject).format,
-            )
-          : null,
-      enum: property.enum
-        ? Object.fromEntries(
-            // Object.values is used because the array is annotated: it contains the __meta symbol used by jsonref.
-            Object.values<string | number>(property.enum).map((enumValue) => [
-              typeof enumValue === "string"
-                ? inflection.humanize(enumValue)
-                : enumValue,
-              enumValue,
-            ]),
-          )
-        : null,
+      type: getType(property.type || "string", property.format),
+      arrayType: getArrayType(property),
+      enum: buildEnumObject(property.enum),
       reference: null,
       embedded: null,
       nullable: property.nullable || false,
@@ -109,9 +100,8 @@ function buildResourceFromSchema(
     if (!property.readOnly) {
       writableFields.push(field);
     }
-
-    return field;
-  });
+    fields.push(field);
+  }
 
   return new Resource(name, url, {
     id: null,
@@ -129,7 +119,7 @@ function buildResourceFromSchema(
 function buildOperationFromPathItem(
   httpMethod: `${OpenAPIV3.HttpMethods}`,
   operationType: OperationType,
-  pathItem: OpenAPIV3.OperationObject,
+  pathItem: OperationObjectDereferenced,
 ): Operation {
   return new Operation(pathItem.summary || operationType, operationType, {
     method: httpMethod.toUpperCase(),
@@ -137,6 +127,13 @@ function buildOperationFromPathItem(
   });
 }
 
+function dereferenceOpenAPIV3(
+  response: OpenAPIV3.Document,
+  options: ParseOptions,
+): Promise<OpenAPIV3DocumentDereferenced> {
+  return parse(response, options);
+}
+
 /*
   Assumptions:
   RESTful APIs typically have two paths per resources: a `/noun` path and a
@@ -151,9 +148,9 @@ export default async function handleJson(
   response: OpenAPIV3.Document,
   entrypointUrl: string,
 ): Promise<Resource[]> {
-  const document = (await dereference(response, {
+  const document = await dereferenceOpenAPIV3(response, {
     scope: entrypointUrl,
-  })) as OpenAPIV3.Document;
+  });
 
   const paths = getResourcePaths(document.paths);
 
@@ -183,20 +180,12 @@ export default async function handleJson(
     if (!showOperation && !editOperation) {
       continue;
     }
+    const showSchema =
+      showOperation?.responses?.["200"]?.content?.["application/json"]
+        ?.schema || document.components?.schemas?.[title];
 
-    const showSchema = showOperation
-      ? (get(
-          showOperation,
-          "responses.200.content.application/json.schema",
-          get(document, `components.schemas[${title}]`),
-        ) as OpenAPIV3.SchemaObject)
-      : null;
-    const editSchema = editOperation
-      ? (get(
-          editOperation,
-          "requestBody.content.application/json.schema",
-        ) as unknown as OpenAPIV3.SchemaObject)
-      : null;
+    const editSchema =
+      editOperation?.requestBody?.content?.["application/json"]?.schema || null;
 
     if (!showSchema && !editSchema) {
       continue;
@@ -244,22 +233,16 @@ export default async function handleJson(
     ];
 
     if (listOperation && listOperation.parameters) {
-      resource.parameters = listOperation.parameters
-        .filter(isParameter)
-        .map(
-          (parameter) =>
-            new Parameter(
-              parameter.name,
-              parameter.schema &&
-              isSchema(parameter.schema) &&
-              parameter.schema.type
-                ? getType(parameter.schema.type)
-                : null,
-              parameter.required || false,
-              parameter.description || "",
-              parameter.deprecated,
-            ),
-        );
+      resource.parameters = listOperation.parameters.map(
+        (parameter) =>
+          new Parameter(
+            parameter.name,
+            parameter.schema?.type ? getType(parameter.schema.type) : null,
+            parameter.required || false,
+            parameter.description || "",
+            parameter.deprecated,
+          ),
+      );
     }
 
     resources.push(resource);
diff --git a/src/openapi3/parseOpenApi3Documentation.ts b/src/openapi3/parseOpenApi3Documentation.ts
index c92adca..1311ce7 100644
--- a/src/openapi3/parseOpenApi3Documentation.ts
+++ b/src/openapi3/parseOpenApi3Documentation.ts
@@ -2,7 +2,7 @@
 import { Api } from "../Api.js";
 import handleJson, { removeTrailingSlash } from "./handleJson.js";
 import type { OpenAPIV3 } from "openapi-types";
-import type { RequestInitExtended } from "./types.js";
+import type { RequestInitExtended } from "../types.js";
 
 export interface ParsedOpenApi3Documentation {
   api: Api;
diff --git a/src/openapi3/types.ts b/src/openapi3/types.ts
deleted file mode 100644
index 17ba138..0000000
--- a/src/openapi3/types.ts
+++ /dev/null
@@ -1,3 +0,0 @@
-export interface RequestInitExtended extends Omit<RequestInit, "headers"> {
-  headers?: HeadersInit | (() => HeadersInit);
-}
diff --git a/src/swagger/handleJson.ts b/src/swagger/handleJson.ts
index 761219a..23b540d 100644
--- a/src/swagger/handleJson.ts
+++ b/src/swagger/handleJson.ts
@@ -1,4 +1,3 @@
-import get from "lodash.get";
 import inflection from "inflection";
 import { Field } from "../Field.js";
 import { Resource } from "../Resource.js";
@@ -8,7 +7,7 @@ import type { OpenAPIV2 } from "openapi-types";
 
 export function removeTrailingSlash(url: string): string {
   if (url.endsWith("/")) {
-    url = url.slice(0, -1);
+    return url.slice(0, -1);
   }
   return url;
 }
@@ -41,31 +40,23 @@ export default function handleJson(
       throw new Error(); // @TODO
     }
 
-    const description = definition.description || "";
-    const properties = definition.properties;
+    const { description = "", properties } = definition;
 
     if (!properties) {
       throw new Error(); // @TODO
     }
 
-    const fieldNames = Object.keys(properties);
-    const requiredFields = get(
-      response,
-      ["definitions", title, "required"],
-      [],
-    ) as string[];
-
-    const fields = fieldNames.map((fieldName) => {
-      const property = properties[fieldName];
+    const requiredFields = response.definitions?.[title]?.required ?? [];
 
+    const fields = Object.entries(properties).map(([fieldName, property]) => {
       return new Field(fieldName, {
         id: null,
         range: null,
         type: getType(
-          get(property, "type", "") as string,
-          get(property, "format", "") as string,
+          typeof property?.type === "string" ? property.type : "",
+          property?.["format"] ?? "",
         ),
-        enum: property?.enum
+        enum: property.enum
           ? Object.fromEntries(
               property.enum.map((enumValue: string | number) => [
                 typeof enumValue === "string"
@@ -78,7 +69,7 @@ export default function handleJson(
         reference: null,
         embedded: null,
         required: requiredFields.some((value) => value === fieldName),
-        description: property?.description || "",
+        description: property.description || "",
       });
     });
 
diff --git a/src/types.ts b/src/types.ts
index a840fcc..257db4f 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -1,3 +1,7 @@
 export type Nullable<T extends Record<string, unknown>> = {
   [P in keyof T]: T[P] | null;
 };
+
+export interface RequestInitExtended extends Omit<RequestInit, "headers"> {
+  headers?: HeadersInit | (() => HeadersInit);
+}