diff --git a/packages/api/src/cache.ts b/packages/api/src/cache.ts
index 4ae4c0a3..3ae170f2 100644
--- a/packages/api/src/cache.ts
+++ b/packages/api/src/cache.ts
@@ -1,7 +1,7 @@
-import type { OASDocument } from './types';
+import type { OASDocument } from 'oas/@types/rmoas.types';
+
 import 'isomorphic-fetch';
 import OpenAPIParser from '@readme/openapi-parser';
-import yaml from 'js-yaml';
 import crypto from 'crypto';
 import findCacheDir from 'find-cache-dir';
 import fs from 'fs';
@@ -11,6 +11,8 @@ import makeDir from 'make-dir';
 
 import { PACKAGE_NAME } from './packageInfo';
 
+import Fetcher from './fetcher';
+
 type CacheStore = Record<string, { path: string; original: string | OASDocument; title?: string; version?: string }>;
 
 export default class Cache {
@@ -26,21 +28,16 @@ export default class Cache {
 
   cached: false | CacheStore;
 
+  fetcher: Fetcher;
+
   constructor(uri: string | OASDocument) {
     Cache.setCacheDir();
     Cache.cacheStore = path.join(Cache.dir, 'cache.json');
     Cache.specsCache = path.join(Cache.dir, 'specs');
 
-    // Resolve OpenAPI definition shorthand accessors from within the ReadMe API Registry.
-    //
-    // Examples:
-    //    - @petstore/v1.0#n6kvf10vakpemvplx
-    //    - @petstore#n6kvf10vakpemvplx
-    this.uri =
-      typeof uri === 'string'
-        ? uri.replace(/^@[a-zA-Z0-9-_]+\/?(.+)#([a-z0-9]+)$/, 'https://dash.readme.com/api/v1/api-registry/$2')
-        : uri;
+    this.fetcher = new Fetcher(uri);
 
+    this.uri = this.fetcher.uri;
     this.uriHash = Cache.getCacheHash(this.uri);
 
     // This should default to false so we have awareness if we've looked at the cache yet.
@@ -88,6 +85,28 @@ export default class Cache {
     await fs.promises.rmdir(Cache.specsCache, { recursive: true });
   }
 
+  static validate(json: any) {
+    if (json.swagger) {
+      throw new Error('Sorry, this module only supports OpenAPI definitions.');
+    }
+
+    // The `validate` method handles dereferencing for us.
+    return OpenAPIParser.validate(json, {
+      dereference: {
+        // If circular `$refs` are ignored they'll remain in the API definition as
+        // `$ref: String`. This allows us to not only do easy circular reference detection but
+        // also stringify and  save dereferenced API definitions back into the cache directory.
+        circular: 'ignore',
+      },
+    }).catch(err => {
+      if (/is not a valid openapi definition/i.test(err.message)) {
+        throw new Error("Sorry, that doesn't look like a valid OpenAPI definition.");
+      }
+
+      throw err;
+    });
+  }
+
   isCached() {
     const cache = this.getCache();
     return cache && this.uriHash in cache;
@@ -129,109 +148,36 @@ export default class Cache {
       return this.uri;
     }
 
-    try {
-      const url = new URL(this.uri);
-      this.uri = url.href;
+    return this.fetcher.load().then(async spec => this.save(spec));
+  }
 
-      return this.saveUrl();
-    } catch (err) {
-      return this.saveFile();
+  save(spec: OASDocument) {
+    if (!fs.existsSync(Cache.dir)) {
+      fs.mkdirSync(Cache.dir, { recursive: true });
     }
-  }
 
-  save(json: Record<string, unknown>) {
-    if (json.swagger) {
-      throw new Error('Sorry, this module only supports OpenAPI definitions.');
+    if (!fs.existsSync(Cache.specsCache)) {
+      fs.mkdirSync(Cache.specsCache, { recursive: true });
     }
 
-    return Promise.resolve(json)
-      .then((res: any) => {
-        // The `validate` method handles dereferencing for us.
-        return OpenAPIParser.validate(res, {
-          dereference: {
-            // If circular `$refs` are ignored they'll remain in the API definition as
-            // `$ref: String`. This allows us to not only do easy circular reference detection but
-            // also stringify and  save dereferenced API definitions back into the cache directory.
-            circular: 'ignore',
-          },
-        }).catch(err => {
-          if (/is not a valid openapi definition/i.test(err.message)) {
-            throw new Error("Sorry, that doesn't look like a valid OpenAPI definition.");
-          }
-
-          throw err;
-        });
-      })
-      .then(async spec => {
-        if (!fs.existsSync(Cache.dir)) {
-          fs.mkdirSync(Cache.dir, { recursive: true });
-        }
-
-        if (!fs.existsSync(Cache.specsCache)) {
-          fs.mkdirSync(Cache.specsCache, { recursive: true });
-        }
-
-        const cache = this.getCache();
-        if (!(this.uriHash in cache)) {
-          const saved = JSON.stringify(spec, null, 2);
-          const jsonHash = crypto.createHash('md5').update(saved).digest('hex');
-
-          cache[this.uriHash] = {
-            path: path.join(Cache.specsCache, `${jsonHash}.json`),
-            original: this.uri,
-            title: 'title' in spec.info ? spec.info.title : undefined,
-            version: 'version' in spec.info ? spec.info.version : undefined,
-          };
-
-          fs.writeFileSync(cache[this.uriHash].path, saved);
-          fs.writeFileSync(Cache.cacheStore, JSON.stringify(cache, null, 2));
-
-          this.cached = cache;
-        }
-
-        return spec;
-      });
-  }
+    const cache = this.getCache();
+    if (!(this.uriHash in cache)) {
+      const saved = JSON.stringify(spec, null, 2);
+      const jsonHash = crypto.createHash('md5').update(saved).digest('hex');
 
-  saveUrl() {
-    const url = this.uri as string;
-    return fetch(url)
-      .then(res => {
-        if (!res.ok) {
-          throw new Error(`Unable to retrieve URL (${url}). Reason: ${res.statusText}`);
-        }
-
-        if (res.headers.get('content-type') === 'application/yaml' || /\.(yaml|yml)/.test(url)) {
-          return res.text().then(text => {
-            return yaml.load(text);
-          });
-        }
-
-        return res.json();
-      })
-      .then((json: Record<string, unknown>) => this.save(json));
-  }
+      cache[this.uriHash] = {
+        path: path.join(Cache.specsCache, `${jsonHash}.json`),
+        original: this.uri,
+        title: 'title' in spec.info ? spec.info.title : undefined,
+        version: 'version' in spec.info ? spec.info.version : undefined,
+      };
 
-  saveFile() {
-    // Support relative paths by resolving them against the cwd.
-    this.uri = path.resolve(process.cwd(), this.uri as string);
+      fs.writeFileSync(cache[this.uriHash].path, saved);
+      fs.writeFileSync(Cache.cacheStore, JSON.stringify(cache, null, 2));
 
-    if (!fs.existsSync(this.uri)) {
-      throw new Error(
-        `Sorry, we were unable to load ${this.uri} OpenAPI definition. Please either supply a URL or a path on your filesystem.`
-      );
+      this.cached = cache;
     }
 
-    const filePath = this.uri;
-
-    return Promise.resolve(fs.readFileSync(filePath, 'utf8'))
-      .then((res: string) => {
-        if (/\.(yaml|yml)/.test(filePath)) {
-          return yaml.load(res);
-        }
-
-        return JSON.parse(res);
-      })
-      .then(json => this.save(json));
+    return spec;
   }
 }
diff --git a/packages/api/src/fetcher.ts b/packages/api/src/fetcher.ts
new file mode 100644
index 00000000..c3428cbf
--- /dev/null
+++ b/packages/api/src/fetcher.ts
@@ -0,0 +1,105 @@
+import type { OASDocument } from 'oas/@types/rmoas.types';
+
+import 'isomorphic-fetch';
+import OpenAPIParser from '@readme/openapi-parser';
+import yaml from 'js-yaml';
+import fs from 'fs';
+import path from 'path';
+
+export default class Fetcher {
+  uri: string | OASDocument;
+
+  constructor(uri: string | OASDocument) {
+    /**
+     * Resolve OpenAPI definition shorthand accessors from within the ReadMe API Registry.
+     *
+     * @example @petstore/v1.0#n6kvf10vakpemvplx
+     * @example @petstore#n6kvf10vakpemvplx
+     */
+    this.uri =
+      typeof uri === 'string'
+        ? uri.replace(/^@[a-zA-Z0-9-_]+\/?(.+)#([a-z0-9]+)$/, 'https://dash.readme.com/api/v1/api-registry/$2')
+        : uri;
+  }
+
+  async load() {
+    if (typeof this.uri !== 'string') {
+      throw new TypeError(
+        "Something disastrous happened and a non-string URI was supplied to the Fetcher library. This shouldn't have happened!"
+      );
+    }
+
+    return Promise.resolve(this.uri)
+      .then(uri => {
+        try {
+          const url = new URL(uri);
+
+          return Fetcher.getURL(url.href);
+        } catch (err) {
+          return Fetcher.getFile(uri);
+        }
+      })
+      .then(res => Fetcher.validate(res))
+      .then(res => res as OASDocument);
+  }
+
+  static getURL(url: string) {
+    // @todo maybe include our user-agent here to identify our request
+    return fetch(url).then(res => {
+      if (!res.ok) {
+        throw new Error(`Unable to retrieve URL (${url}). Reason: ${res.statusText}`);
+      }
+
+      if (res.headers.get('content-type') === 'application/yaml' || /\.(yaml|yml)/.test(url)) {
+        return res.text().then(text => {
+          return yaml.load(text);
+        });
+      }
+
+      return res.json();
+    });
+  }
+
+  static getFile(uri: string) {
+    // Support relative paths by resolving them against the cwd.
+    const file = path.resolve(process.cwd(), uri);
+
+    if (!fs.existsSync(file)) {
+      throw new Error(
+        `Sorry, we were unable to load an API definition from ${file}. Please either supply a URL or a path on your filesystem.`
+      );
+    }
+
+    return Promise.resolve(fs.readFileSync(file, 'utf8')).then((res: string) => {
+      if (/\.(yaml|yml)/.test(file)) {
+        return yaml.load(res);
+      }
+
+      return JSON.parse(res);
+    });
+  }
+
+  static validate(json: any) {
+    if (json.swagger) {
+      throw new Error('Sorry, this module only supports OpenAPI definitions.');
+    }
+
+    // The `validate` method handles dereferencing for us.
+    return OpenAPIParser.validate(json, {
+      dereference: {
+        /**
+         * If circular `$refs` are ignored they'll remain in the API definition as `$ref: String`.
+         * This allows us to not only do easy circular reference detection but also stringify and
+         * save dereferenced API definitions back into the cache directory.
+         */
+        circular: 'ignore',
+      },
+    }).catch(err => {
+      if (/is not a valid openapi definition/i.test(err.message)) {
+        throw new Error("Sorry, that doesn't look like a valid OpenAPI definition.");
+      }
+
+      throw err;
+    });
+  }
+}
diff --git a/packages/api/src/index.ts b/packages/api/src/index.ts
index 06b1f1d9..77390425 100644
--- a/packages/api/src/index.ts
+++ b/packages/api/src/index.ts
@@ -1,6 +1,5 @@
 import type { Operation } from 'oas';
-import type { OASDocument } from './types';
-import type { HttpMethods } from 'oas/@types/rmoas.types';
+import type { HttpMethods, OASDocument } from 'oas/@types/rmoas.types';
 import type { ConfigOptions } from './core';
 
 import Oas from 'oas';
diff --git a/packages/api/src/types.ts b/packages/api/src/types.ts
deleted file mode 100644
index e6b83745..00000000
--- a/packages/api/src/types.ts
+++ /dev/null
@@ -1,9 +0,0 @@
-// We should eventually merge this in with the `OASDocument` type that `oas` provides, or use
-// the `openapi-types` library, but both of those currently have a lot of issues with seemingly
-// valid specs busting types because of problems in `openapi-types`.
-//
-// For example with the `@readme/oas-examples/3.0/json/security.json` definition it thinks that
-// the `apiKey_cookie` security scheme isn't a valid apiKey security scheme despite it absolutely
-// being valid. Or with `@readme/oas-examples/3.0/json/petstore.json` it thinks that the `Order`
-// component isn't valid at all.
-export type OASDocument = Record<string, unknown>;
diff --git a/packages/api/test/auth.test.ts b/packages/api/test/auth.test.ts
index 71ba9bec..55cd6a6d 100644
--- a/packages/api/test/auth.test.ts
+++ b/packages/api/test/auth.test.ts
@@ -1,4 +1,6 @@
 /* eslint-disable mocha/no-setup-in-describe */
+import type { OASDocument } from 'oas/@types/rmoas.types';
+
 import { assert, expect } from 'chai';
 import nock from 'nock';
 import uniqueTempDir from 'unique-temp-dir';
@@ -22,7 +24,7 @@ describe('#auth()', function () {
   });
 
   beforeEach(function () {
-    sdk = api(securityOas);
+    sdk = api(securityOas as unknown as OASDocument);
   });
 
   describe('API Keys', function () {
diff --git a/packages/api/test/cache.test.ts b/packages/api/test/cache.test.ts
index a75a1f34..f3d8279f 100644
--- a/packages/api/test/cache.test.ts
+++ b/packages/api/test/cache.test.ts
@@ -1,3 +1,5 @@
+import type { OASDocument } from 'oas/@types/rmoas.types';
+
 import chai, { assert, expect } from 'chai';
 import uniqueTempDir from 'unique-temp-dir';
 import nock from 'nock';
@@ -19,28 +21,10 @@ describe('cache', function () {
 
   describe('#load', function () {
     it('should return a raw object if a JSON object was initially supplied', async function () {
-      const res = await new Cache(readmeSpec).load();
+      const res = await new Cache(readmeSpec as unknown as OASDocument).load();
       expect(res).to.deep.equal(readmeSpec);
     });
 
-    describe('shorthand accessors', function () {
-      it('should resolve the shorthand `@petstore/v1.0#uuid` syntax to the ReadMe API', function () {
-        expect(new Cache('@petstore/v1.0#n6kvf10vakpemvplx').uri).to.equal(
-          'https://dash.readme.com/api/v1/api-registry/n6kvf10vakpemvplx'
-        );
-      });
-
-      it('should resolve the shorthand `@petstore#uuid` syntax to the ReadMe API', function () {
-        expect(new Cache('@petstore#n6kvf10vakpemvplx').uri).to.equal(
-          'https://dash.readme.com/api/v1/api-registry/n6kvf10vakpemvplx'
-        );
-      });
-
-      it("shouldn't try to resolve improperly formatted shorthand accessors to the ReadMe API", function () {
-        expect(new Cache('n6kvf10vakpemvplx').uri).to.equal('n6kvf10vakpemvplx');
-      });
-    });
-
     it('should throw an error when a non-HTTP(S) url is supplied', async function () {
       await new Cache('htt://example.com/openapi.json')
         .load()
@@ -58,106 +42,149 @@ describe('cache', function () {
           expect(err.message).to.match(/supply a URL or a path on your filesystem/);
         });
     });
-  });
 
-  describe('#saveUrl()', function () {
-    it('should be able to save a definition', async function () {
-      const mock = nock('http://example.com').get('/readme.json').reply(200, readmeSpec);
-      const cacheStore = new Cache('http://example.com/readme.json');
+    describe('ReadMe registry UUID', function () {
+      it('should resolve the shorthand `@petstore/v1.0#uuid` syntax to the ReadMe API', function () {
+        expect(new Cache('@petstore/v1.0#n6kvf10vakpemvplx').uri).to.equal(
+          'https://dash.readme.com/api/v1/api-registry/n6kvf10vakpemvplx'
+        );
+      });
 
-      expect(cacheStore.isCached()).to.be.false;
+      it('should resolve the shorthand `@petstore#uuid` syntax to the ReadMe API', function () {
+        expect(new Cache('@petstore#n6kvf10vakpemvplx').uri).to.equal(
+          'https://dash.readme.com/api/v1/api-registry/n6kvf10vakpemvplx'
+        );
+      });
 
-      expect(await cacheStore.saveUrl()).to.have.deep.property('info', {
-        description: 'Create beautiful product and API documentation with our developer friendly platform.',
-        version: '2.0.0',
-        title: 'API Endpoints',
-        contact: {
-          email: 'support@readme.io',
-          name: 'API Support',
-          url: 'https://docs.readme.com/docs/contact-support',
-        },
+      it("shouldn't try to resolve improperly formatted shorthand accessors to the ReadMe API", function () {
+        expect(new Cache('n6kvf10vakpemvplx').uri).to.equal('n6kvf10vakpemvplx');
       });
 
-      expect(cacheStore.get().paths['/api-specification'].get.parameters).to.be.dereferenced;
-      expect(cacheStore.isCached()).to.be.true;
-      mock.done();
-    });
+      it('should be able to load a definition', async function () {
+        const mock = nock('https://dash.readme.com')
+          .get('/api/v1/api-registry/n6kvf10vakpemvplxn')
+          .reply(200, readmeSpec);
 
-    it('should error if the url cannot be reached', async function () {
-      const mock = nock('http://example.com').get('/unknown.json').reply(404);
+        const cacheStore = new Cache('@readme/v1.0#n6kvf10vakpemvplxn');
 
-      await new Cache('http://example.com/unknown.json')
-        .saveUrl()
-        .then(() => assert.fail())
-        .catch(err => {
-          expect(err.message).to.equal('Unable to retrieve URL (http://example.com/unknown.json). Reason: Not Found');
+        expect(cacheStore.isCached()).to.be.false;
+
+        expect(await cacheStore.load()).to.have.deep.property('info', {
+          description: 'Create beautiful product and API documentation with our developer friendly platform.',
+          version: '2.0.0',
+          title: 'API Endpoints',
+          contact: {
+            email: 'support@readme.io',
+            name: 'API Support',
+            url: 'https://docs.readme.com/docs/contact-support',
+          },
         });
 
-      mock.done();
+        expect(cacheStore.get().paths['/api-specification'].get.parameters).to.be.dereferenced;
+        expect(cacheStore.isCached()).to.be.true;
+        mock.done();
+      });
     });
 
-    it('should convert yaml to json', async function () {
-      const spec = await fs.readFile(require.resolve('@readme/oas-examples/3.0/yaml/readme.yaml'), 'utf8');
-      const mock = nock('http://example.com').get('/readme.yaml').reply(200, spec);
+    describe('URL', function () {
+      it('should be able to load a definition', async function () {
+        const mock = nock('http://example.com').get('/readme.json').reply(200, readmeSpec);
+        const cacheStore = new Cache('http://example.com/readme.json');
+
+        expect(cacheStore.isCached()).to.be.false;
+
+        expect(await cacheStore.load()).to.have.deep.property('info', {
+          description: 'Create beautiful product and API documentation with our developer friendly platform.',
+          version: '2.0.0',
+          title: 'API Endpoints',
+          contact: {
+            email: 'support@readme.io',
+            name: 'API Support',
+            url: 'https://docs.readme.com/docs/contact-support',
+          },
+        });
+
+        expect(cacheStore.get().paths['/api-specification'].get.parameters).to.be.dereferenced;
+        expect(cacheStore.isCached()).to.be.true;
+        mock.done();
+      });
 
-      const definition = 'http://example.com/readme.yaml';
-      const cacheStore = new Cache(definition);
-      const hash = Cache.getCacheHash(definition);
+      it('should error if the url cannot be reached', async function () {
+        const mock = nock('http://example.com').get('/unknown.json').reply(404);
 
-      expect(cacheStore.isCached()).to.be.false;
+        await new Cache('http://example.com/unknown.json')
+          .load()
+          .then(() => assert.fail())
+          .catch(err => {
+            expect(err.message).to.equal('Unable to retrieve URL (http://example.com/unknown.json). Reason: Not Found');
+          });
 
-      await cacheStore.saveUrl();
-      expect(cacheStore.get().paths['/api-specification'].get.parameters).to.be.dereferenced;
-      expect(cacheStore.isCached()).to.be.true;
-      mock.done();
+        mock.done();
+      });
 
-      const cached = cacheStore.getCache();
-      expect(cached).to.have.property(hash);
-      expect(cached[hash].path).to.match(/\.json$/);
-    });
-  });
+      it('should convert yaml to json', async function () {
+        const spec = await fs.readFile(require.resolve('@readme/oas-examples/3.0/yaml/readme.yaml'), 'utf8');
+        const mock = nock('http://example.com').get('/readme.yaml').reply(200, spec);
 
-  describe('#saveFile()', function () {
-    it('should be able to save a definition', async function () {
-      const cacheStore = new Cache(require.resolve('@readme/oas-examples/3.0/json/readme.json'));
+        const definition = 'http://example.com/readme.yaml';
+        const cacheStore = new Cache(definition);
+        const hash = Cache.getCacheHash(definition);
 
-      expect(cacheStore.isCached()).to.be.false;
+        expect(cacheStore.isCached()).to.be.false;
 
-      await cacheStore.saveFile();
-      expect(cacheStore.get().paths['/api-specification'].get.parameters).to.be.dereferenced;
-      expect(cacheStore.isCached()).to.be.true;
+        await cacheStore.load();
+        expect(cacheStore.get().paths['/api-specification'].get.parameters).to.be.dereferenced;
+        expect(cacheStore.isCached()).to.be.true;
+        mock.done();
+
+        const cached = cacheStore.getCache();
+        expect(cached).to.have.property(hash);
+        expect(cached[hash].path).to.match(/\.json$/);
+      });
     });
 
-    it('should be able handle a relative path', async function () {
-      const cacheStore = new Cache('../api/test/__fixtures__/oas.json');
+    describe('file', function () {
+      it('should be able to load a definition', async function () {
+        const cacheStore = new Cache(require.resolve('@readme/oas-examples/3.0/json/readme.json'));
 
-      expect(cacheStore.isCached()).to.be.false;
+        expect(cacheStore.isCached()).to.be.false;
 
-      await cacheStore.saveFile();
-      expect(cacheStore.isCached()).to.be.true;
-    });
+        await cacheStore.load();
+        expect(cacheStore.get().paths['/api-specification'].get.parameters).to.be.dereferenced;
+        expect(cacheStore.isCached()).to.be.true;
+      });
 
-    it('should convert yaml to json', async function () {
-      const file = require.resolve('@readme/oas-examples/3.0/yaml/readme.yaml');
-      const cacheStore = new Cache(file);
-      const hash = Cache.getCacheHash(file);
+      it('should be able to handle a relative path', async function () {
+        const cacheStore = new Cache('../api/test/__fixtures__/oas.json');
 
-      expect(cacheStore.isCached()).to.be.false;
+        expect(cacheStore.isCached()).to.be.false;
 
-      await cacheStore.saveFile();
-      expect(cacheStore.get().paths['/api-specification'].get.parameters).to.be.dereferenced;
-      expect(cacheStore.isCached()).to.be.true;
+        await cacheStore.load();
+        expect(cacheStore.isCached()).to.be.true;
+      });
+
+      it('should convert yaml to json', async function () {
+        const file = require.resolve('@readme/oas-examples/3.0/yaml/readme.yaml');
+        const cacheStore = new Cache(file);
+        const hash = Cache.getCacheHash(file);
+
+        expect(cacheStore.isCached()).to.be.false;
 
-      const cached = cacheStore.getCache();
-      expect(cached).to.have.property(hash);
-      expect(cached[hash].path).to.match(/\.json$/);
+        await cacheStore.load();
+        expect(cacheStore.get().paths['/api-specification'].get.parameters).to.be.dereferenced;
+        expect(cacheStore.isCached()).to.be.true;
+
+        const cached = cacheStore.getCache();
+        expect(cached).to.have.property(hash);
+        expect(cached[hash].path).to.match(/\.json$/);
+      });
     });
   });
 
   describe('#save()', function () {
     it('should error if definition is a swagger file', async function () {
       await new Cache(require.resolve('@readme/oas-examples/2.0/json/petstore.json'))
-        .saveFile()
+        .load()
         .then(() => assert.fail())
         .catch(err => {
           expect(err.message).to.equal('Sorry, this module only supports OpenAPI definitions.');
@@ -166,7 +193,7 @@ describe('cache', function () {
 
     it('should error if definition is not a valid openapi file', async function () {
       await new Cache(require.resolve('../package.json'))
-        .saveFile()
+        .load()
         .then(() => assert.fail())
         .catch(err => {
           expect(err.message).to.equal("Sorry, that doesn't look like a valid OpenAPI definition.");
@@ -181,7 +208,7 @@ describe('cache', function () {
 
       expect(cacheStore.isCached()).to.be.false;
 
-      await cacheStore.saveFile();
+      await cacheStore.load();
 
       expect(cacheStore.isCached()).to.be.true;
     });
@@ -192,7 +219,7 @@ describe('cache', function () {
 
       expect(cacheStore.isCached()).to.be.false;
 
-      await cacheStore.saveFile();
+      await cacheStore.load();
 
       expect(cacheStore.isCached()).to.be.true;
     });
@@ -203,7 +230,7 @@ describe('cache', function () {
 
       expect(cacheStore.isCached()).to.be.false;
 
-      await cacheStore.saveFile();
+      await cacheStore.load();
 
       expect(cacheStore.isCached()).to.be.true;
     });
@@ -211,8 +238,7 @@ describe('cache', function () {
 
   describe('#get', function () {
     it('should return an object if the current uri is an object (used for unit testing)', function () {
-      // const obj = JSON.parse(readmeExampleJson);
-      const loaded = new Cache(readmeSpec).get();
+      const loaded = new Cache(readmeSpec as unknown as OASDocument).get();
 
       expect(loaded).to.deep.equal(readmeSpec);
     });
@@ -220,7 +246,7 @@ describe('cache', function () {
     it('should load a file out of cache', async function () {
       const file = require.resolve('@readme/oas-examples/3.0/json/readme.json');
       const cacheStore = new Cache(file);
-      await cacheStore.saveFile();
+      await cacheStore.load();
 
       const loaded = cacheStore.get();
       expect(loaded).to.have.property('components');
diff --git a/packages/api/test/config.test.ts b/packages/api/test/config.test.ts
index 984b2b10..1015b109 100644
--- a/packages/api/test/config.test.ts
+++ b/packages/api/test/config.test.ts
@@ -1,3 +1,5 @@
+import type { OASDocument } from 'oas/@types/rmoas.types';
+
 import { expect } from 'chai';
 import nock from 'nock';
 import uniqueTempDir from 'unique-temp-dir';
@@ -24,7 +26,7 @@ describe('#config()', function () {
 
   describe('parseResponse', function () {
     beforeEach(function () {
-      sdk = api(petstore);
+      sdk = api(petstore as unknown as OASDocument);
     });
 
     it('should give access to the Response object if `parseResponse` is `false`', async function () {
diff --git a/packages/api/test/core/prepareAuth.test.ts b/packages/api/test/core/prepareAuth.test.ts
index 770a86cb..0f7141ba 100644
--- a/packages/api/test/core/prepareAuth.test.ts
+++ b/packages/api/test/core/prepareAuth.test.ts
@@ -1,10 +1,12 @@
+import type { OASDocument } from 'oas/@types/rmoas.types';
+
 import { expect } from 'chai';
 import Oas from 'oas';
 import prepareAuth from '../../src/core/prepareAuth';
 
 import securityOas from '@readme/oas-examples/3.0/json/security.json';
 
-const oas = Oas.init(securityOas);
+const oas = Oas.init(securityOas as unknown as OASDocument);
 
 describe('#prepareAuth()', function () {
   describe('apiKey', function () {
diff --git a/packages/api/test/dist.test.ts b/packages/api/test/dist.test.ts
index b076998a..8b870c02 100644
--- a/packages/api/test/dist.test.ts
+++ b/packages/api/test/dist.test.ts
@@ -1,3 +1,5 @@
+import type { OASDocument } from 'oas/@types/rmoas.types';
+
 import { expect } from 'chai';
 import nock from 'nock';
 import uniqueTempDir from 'unique-temp-dir';
@@ -21,7 +23,7 @@ describe('typescript dist verification', function () {
       .post('/oa_citations/v1/records')
       .reply(200, uri => uri);
 
-    const sdk = api(uspto);
+    const sdk = api(uspto as unknown as OASDocument);
 
     expect(await sdk.post('/oa_citations/v1/records')).to.equal('/ds-api/oa_citations/v1/records');
 
@@ -39,7 +41,7 @@ describe('typescript dist verification', function () {
         return this.req.headers;
       });
 
-    const sdk = api(securityOas);
+    const sdk = api(securityOas as unknown as OASDocument);
 
     sdk.auth(user, pass);
     expect(await sdk.post('/anything/basic')).to.have.deep.property('authorization', [authHeader]);
diff --git a/packages/api/test/fetcher.test.ts b/packages/api/test/fetcher.test.ts
new file mode 100644
index 00000000..8e0276b7
--- /dev/null
+++ b/packages/api/test/fetcher.test.ts
@@ -0,0 +1,151 @@
+import chai, { assert, expect } from 'chai';
+import nock from 'nock';
+import chaiPlugins from './helpers/chai-plugins';
+import fs from 'fs/promises';
+import Fetcher from '../src/fetcher';
+
+import readmeSpec from '@readme/oas-examples/3.0/json/readme.json';
+
+chai.use(chaiPlugins);
+
+describe('fetcher', function () {
+  describe('#load', function () {
+    it('should throw an error when a non-HTTP(S) url is supplied', async function () {
+      await new Fetcher('htt://example.com/openapi.json')
+        .load()
+        .then(() => assert.fail())
+        .catch(err => {
+          expect(err.message).to.equal('Only HTTP(S) protocols are supported');
+        });
+    });
+
+    it('should throw an error if neither a url or file are detected', async function () {
+      await new Fetcher('/this/is/not/a/real/path.json')
+        .load()
+        .then(() => assert.fail())
+        .catch(err => {
+          expect(err.message).to.match(/supply a URL or a path on your filesystem/);
+        });
+    });
+
+    describe('ReadMe registry UUID', function () {
+      it('should resolve the shorthand `@petstore/v1.0#uuid` syntax to the ReadMe API', function () {
+        expect(new Fetcher('@petstore/v1.0#n6kvf10vakpemvplx').uri).to.equal(
+          'https://dash.readme.com/api/v1/api-registry/n6kvf10vakpemvplx'
+        );
+      });
+
+      it('should resolve the shorthand `@petstore#uuid` syntax to the ReadMe API', function () {
+        expect(new Fetcher('@petstore#n6kvf10vakpemvplx').uri).to.equal(
+          'https://dash.readme.com/api/v1/api-registry/n6kvf10vakpemvplx'
+        );
+      });
+
+      it("shouldn't try to resolve improperly formatted shorthand accessors to the ReadMe API", function () {
+        expect(new Fetcher('n6kvf10vakpemvplx').uri).to.equal('n6kvf10vakpemvplx');
+      });
+
+      it('should be able to load a definition', async function () {
+        const mock = nock('https://dash.readme.com')
+          .get('/api/v1/api-registry/n6kvf10vakpemvplxn')
+          .reply(200, readmeSpec);
+
+        const fetcher = new Fetcher('@readme/v1.0#n6kvf10vakpemvplxn');
+
+        expect(await fetcher.load()).to.have.deep.property('info', {
+          description: 'Create beautiful product and API documentation with our developer friendly platform.',
+          version: '2.0.0',
+          title: 'API Endpoints',
+          contact: {
+            email: 'support@readme.io',
+            name: 'API Support',
+            url: 'https://docs.readme.com/docs/contact-support',
+          },
+        });
+
+        mock.done();
+      });
+    });
+
+    describe('URL', function () {
+      it('should be able to load a definition', async function () {
+        const mock = nock('http://example.com').get('/readme.json').reply(200, readmeSpec);
+        const fetcher = new Fetcher('http://example.com/readme.json');
+
+        expect(await fetcher.load()).to.have.deep.property('info', {
+          description: 'Create beautiful product and API documentation with our developer friendly platform.',
+          version: '2.0.0',
+          title: 'API Endpoints',
+          contact: {
+            email: 'support@readme.io',
+            name: 'API Support',
+            url: 'https://docs.readme.com/docs/contact-support',
+          },
+        });
+
+        mock.done();
+      });
+
+      it('should error if the url cannot be reached', async function () {
+        const mock = nock('http://example.com').get('/unknown.json').reply(404);
+
+        await new Fetcher('http://example.com/unknown.json')
+          .load()
+          .then(() => assert.fail())
+          .catch(err => {
+            expect(err.message).to.equal('Unable to retrieve URL (http://example.com/unknown.json). Reason: Not Found');
+          });
+
+        mock.done();
+      });
+
+      it('should convert yaml to json', async function () {
+        const spec = await fs.readFile(require.resolve('@readme/oas-examples/3.0/yaml/readme.yaml'), 'utf8');
+        const mock = nock('http://example.com').get('/readme.yaml').reply(200, spec);
+
+        const definition = 'http://example.com/readme.yaml';
+        const fetcher = new Fetcher(definition);
+
+        expect(await fetcher.load()).to.have.deep.property('info', {
+          description: 'Create beautiful product and API documentation with our developer friendly platform.',
+          version: '2.0.0',
+          title: 'API Endpoints',
+          contact: {
+            email: 'support@readme.io',
+            name: 'API Support',
+            url: 'https://docs.readme.com/docs/contact-support',
+          },
+        });
+
+        mock.done();
+      });
+    });
+
+    describe('file', function () {
+      it('should be able to load a definition', async function () {
+        const fetcher = new Fetcher(require.resolve('@readme/oas-examples/3.0/json/readme.json'));
+
+        const res = await fetcher.load();
+        expect(res.paths['/api-specification'].get.parameters).to.be.dereferenced;
+      });
+
+      it('should be able to handle a relative path', async function () {
+        const fetcher = new Fetcher('../api/test/__fixtures__/oas.json');
+
+        expect(await fetcher.load()).to.have.deep.property('info', {
+          version: '1.0.0',
+          title: 'Single Path',
+          description: 'This is a slimmed down single path version of the Petstore definition.',
+        });
+      });
+
+      it('should convert yaml to json', async function () {
+        const file = require.resolve('@readme/oas-examples/3.0/yaml/readme.yaml');
+        const fetcher = new Fetcher(file);
+
+        const res = await fetcher.load();
+        expect(res.paths['/api-specification'].get.parameters).to.be.dereferenced;
+      });
+    });
+  });
+});
diff --git a/packages/api/test/index.test.ts b/packages/api/test/index.test.ts
index 1928502d..687c44b7 100644
--- a/packages/api/test/index.test.ts
+++ b/packages/api/test/index.test.ts
@@ -1,3 +1,5 @@
+import type { OASDocument } from 'oas/@types/rmoas.types';
+
 import { assert, expect } from 'chai';
 import uniqueTempDir from 'unique-temp-dir';
 import nock from 'nock';
@@ -20,11 +22,11 @@ describe('api', function () {
 
   beforeEach(async function () {
     const petstore = require.resolve('@readme/oas-examples/3.0/json/petstore-expanded.json');
-    await new Cache(petstore).saveFile();
+    await new Cache(petstore).load();
     petstoreSdk = api(petstore);
 
     const readme = require.resolve('@readme/oas-examples/3.0/json/readme.json');
-    await new Cache(readme).saveFile();
+    await new Cache(readme).load();
     readmeSdk = api(readme);
   });
 
@@ -305,7 +307,7 @@ describe('api', function () {
               },
             },
           },
-        });
+        } as unknown as OASDocument);
       });
 
       it('should encode query parameters', async function () {
diff --git a/packages/api/test/integration.test.ts b/packages/api/test/integration.test.ts
index 0c5698d3..86432e4a 100644
--- a/packages/api/test/integration.test.ts
+++ b/packages/api/test/integration.test.ts
@@ -1,3 +1,5 @@
+import type { OASDocument } from 'oas/@types/rmoas.types';
+
 import chai, { expect } from 'chai';
 import nock from 'nock';
 import uniqueTempDir from 'unique-temp-dir';
@@ -105,7 +107,7 @@ describe('integration tests', function () {
 
     const file = `${__dirname}/__fixtures__/owlbert.png`;
 
-    const res = await api(fileUploads).post('/anything/image-png', file);
+    const res = await api(fileUploads as unknown as OASDocument).post('/anything/image-png', file);
     expect(res.uri).to.equal('/anything/image-png');
     expect(res.requestBody).to.equal(await datauri(file));
     expect(res.headers).to.have.deep.property('content-type', ['image/png']);
@@ -137,7 +139,7 @@ describe('integration tests', function () {
         },
       };
 
-      const res = await api(parametersStyle).post('/anything/form-data/form', body);
+      const res = await api(parametersStyle as unknown as OASDocument).post('/anything/form-data/form', body);
       expect(res.uri).to.equal('/anything/form-data/form');
       expect(res.requestBody.split(`--${res.boundary}`).filter(Boolean)).to.deep.equal([
         '\r\nContent-Disposition: form-data; name="primitive"\r\n\r\nstring\r\n',
@@ -172,7 +174,7 @@ describe('integration tests', function () {
           documentFile: `${__dirname}/__fixtures__/hello.txt`,
         };
 
-        const res = await api(fileUploads).post('/anything/multipart-formdata', body);
+        const res = await api(fileUploads as unknown as OASDocument).post('/anything/multipart-formdata', body);
         expect(res.uri).to.equal('/anything/multipart-formdata');
         expect(res.requestBody.split(`--${res.boundary}`).filter(Boolean)).to.deep.equal([
           '\r\nContent-Disposition: form-data; name="orderId"\r\n\r\n1234\r\n',
@@ -204,7 +206,7 @@ describe('integration tests', function () {
           documentFile: `${__dirname}/__fixtures__/hello.jp.txt`,
         };
 
-        const res = await api(fileUploads).post('/anything/multipart-formdata', body);
+        const res = await api(fileUploads as unknown as OASDocument).post('/anything/multipart-formdata', body);
         expect(res.uri).to.equal('/anything/multipart-formdata');
         expect(res.requestBody.split(`--${res.boundary}`).filter(Boolean)).to.deep.equal([
           '\r\nContent-Disposition: form-data; name="documentFile"; filename="hello.jp.txt"\r\nContent-Type: text/plain\r\n\r\n速い茶色のキツネは怠惰な犬を飛び越えます\n\r\n',