diff --git a/lib/gavel.js b/lib/gavel.js
index b9b859f2..353cc79b 100644
--- a/lib/gavel.js
+++ b/lib/gavel.js
@@ -1,15 +1,17 @@
 const { HttpRequest, ExpectedHttpRequest } = require('./model/http-request');
 const { HttpResponse, ExpectedHttpResponse } = require('./model/http-response');
-
 const { isValid, isValidatable } = require('./validate');
-const validate = require('./api/validate');
+const validate = require('./next/validate');
 
 module.exports = {
+  // next
+  validate,
+
+  // legacy
   HttpRequest,
   HttpResponse,
   ExpectedHttpRequest,
   ExpectedHttpResponse,
-  validate,
   isValid,
   isValidatable
 };
diff --git a/lib/api/test/integration/validateMessage.test.js b/lib/next/test/integration/validateMessage.test.js
similarity index 100%
rename from lib/api/test/integration/validateMessage.test.js
rename to lib/next/test/integration/validateMessage.test.js
diff --git a/lib/api/test/unit/units/normalize/normalizeHeaders.test.js b/lib/next/test/unit/units/normalize/normalizeHeaders.test.js
similarity index 100%
rename from lib/api/test/unit/units/normalize/normalizeHeaders.test.js
rename to lib/next/test/unit/units/normalize/normalizeHeaders.test.js
diff --git a/lib/api/test/unit/units/normalize/normalizeStatusCode.test.js b/lib/next/test/unit/units/normalize/normalizeStatusCode.test.js
similarity index 100%
rename from lib/api/test/unit/units/normalize/normalizeStatusCode.test.js
rename to lib/next/test/unit/units/normalize/normalizeStatusCode.test.js
diff --git a/lib/api/test/unit/units/validateBody.test.js b/lib/next/test/unit/units/validateBody.test.js
similarity index 100%
rename from lib/api/test/unit/units/validateBody.test.js
rename to lib/next/test/unit/units/validateBody.test.js
diff --git a/lib/api/test/unit/units/validateBody/getBodySchemaType.test.js b/lib/next/test/unit/units/validateBody/getBodySchemaType.test.js
similarity index 100%
rename from lib/api/test/unit/units/validateBody/getBodySchemaType.test.js
rename to lib/next/test/unit/units/validateBody/getBodySchemaType.test.js
diff --git a/lib/api/test/unit/units/validateBody/getBodyType.test.js b/lib/next/test/unit/units/validateBody/getBodyType.test.js
similarity index 100%
rename from lib/api/test/unit/units/validateBody/getBodyType.test.js
rename to lib/next/test/unit/units/validateBody/getBodyType.test.js
diff --git a/lib/api/test/unit/units/validateBody/getBodyValidator.test.js b/lib/next/test/unit/units/validateBody/getBodyValidator.test.js
similarity index 100%
rename from lib/api/test/unit/units/validateBody/getBodyValidator.test.js
rename to lib/next/test/unit/units/validateBody/getBodyValidator.test.js
diff --git a/lib/api/test/unit/units/validateBody/isJson.test.js b/lib/next/test/unit/units/validateBody/isJson.test.js
similarity index 100%
rename from lib/api/test/unit/units/validateBody/isJson.test.js
rename to lib/next/test/unit/units/validateBody/isJson.test.js
diff --git a/lib/api/test/unit/units/validateBody/isJsonContentType.test.js b/lib/next/test/unit/units/validateBody/isJsonContentType.test.js
similarity index 100%
rename from lib/api/test/unit/units/validateBody/isJsonContentType.test.js
rename to lib/next/test/unit/units/validateBody/isJsonContentType.test.js
diff --git a/lib/api/test/unit/units/validateBody/isJsonSchema.test.js b/lib/next/test/unit/units/validateBody/isJsonSchema.test.js
similarity index 100%
rename from lib/api/test/unit/units/validateBody/isJsonSchema.test.js
rename to lib/next/test/unit/units/validateBody/isJsonSchema.test.js
diff --git a/lib/api/test/unit/units/validateHeaders.test.js b/lib/next/test/unit/units/validateHeaders.test.js
similarity index 100%
rename from lib/api/test/unit/units/validateHeaders.test.js
rename to lib/next/test/unit/units/validateHeaders.test.js
diff --git a/lib/api/test/unit/units/validateStatusCode.test.js b/lib/next/test/unit/units/validateStatusCode.test.js
similarity index 100%
rename from lib/api/test/unit/units/validateStatusCode.test.js
rename to lib/next/test/unit/units/validateStatusCode.test.js
diff --git a/lib/api/test/unit/utils/evolve.test.js b/lib/next/test/unit/utils/evolve.test.js
similarity index 100%
rename from lib/api/test/unit/utils/evolve.test.js
rename to lib/next/test/unit/utils/evolve.test.js
diff --git a/lib/api/units/normalize/index.js b/lib/next/units/normalize/index.js
similarity index 100%
rename from lib/api/units/normalize/index.js
rename to lib/next/units/normalize/index.js
diff --git a/lib/api/units/normalize/normalizeHeaders.js b/lib/next/units/normalize/normalizeHeaders.js
similarity index 100%
rename from lib/api/units/normalize/normalizeHeaders.js
rename to lib/next/units/normalize/normalizeHeaders.js
diff --git a/lib/api/units/normalize/normalizeStatusCode.js b/lib/next/units/normalize/normalizeStatusCode.js
similarity index 100%
rename from lib/api/units/normalize/normalizeStatusCode.js
rename to lib/next/units/normalize/normalizeStatusCode.js
diff --git a/lib/api/units/validateBody.js b/lib/next/units/validateBody.js
similarity index 100%
rename from lib/api/units/validateBody.js
rename to lib/next/units/validateBody.js
diff --git a/lib/api/units/validateHeaders.js b/lib/next/units/validateHeaders.js
similarity index 100%
rename from lib/api/units/validateHeaders.js
rename to lib/next/units/validateHeaders.js
diff --git a/lib/api/units/validateStatusCode.js b/lib/next/units/validateStatusCode.js
similarity index 100%
rename from lib/api/units/validateStatusCode.js
rename to lib/next/units/validateStatusCode.js
diff --git a/lib/api/utils/evolve.js b/lib/next/utils/evolve.js
similarity index 100%
rename from lib/api/utils/evolve.js
rename to lib/next/utils/evolve.js
diff --git a/lib/api/validate.js b/lib/next/validate.js
similarity index 67%
rename from lib/api/validate.js
rename to lib/next/validate.js
index b149fa00..14a6859a 100644
--- a/lib/api/validate.js
+++ b/lib/next/validate.js
@@ -1,5 +1,13 @@
 const { validateMessage } = require('./validateMessage');
 
+/**
+ * Validates the given HTTP messages pair and returns
+ * a legacy-compliant validation results.
+ * @param {Object} real
+ * @param {Object} expected
+ * @param {'request'|'response'} type
+ * @param {(error: Error, result: Object) => void} callback
+ */
 function validate(real, expected, type, callback) {
   if (type !== 'request' && type !== 'response') {
     throw new Error(
diff --git a/lib/api/validateMessage.js b/lib/next/validateMessage.js
similarity index 100%
rename from lib/api/validateMessage.js
rename to lib/next/validateMessage.js
diff --git a/lib/validate.js b/lib/validate.js
index 184612fc..2c6ea453 100644
--- a/lib/validate.js
+++ b/lib/validate.js
@@ -19,15 +19,22 @@ function proxy(validatableObject, method, cb) {
  * @param {'request'|'response'} type
  */
 function getValidatableObject(real, expected, type) {
+  let request;
+  let response;
+
   switch (type) {
     case 'request':
-      const request = new HttpRequest(real);
+      request = new HttpRequest(real);
       request.expected = new ExpectedHttpRequest(expected);
       return request;
     case 'response':
-      const response = new HttpResponse(real);
+      response = new HttpResponse(real);
       response.expected = new ExpectedHttpResponse(expected);
       return response;
+    default:
+      throw new Error(
+        `Can't validate: expected HTTP message type to be "request" or "response", but got: ${type}.`
+      );
   }
 }
 
diff --git a/package.json b/package.json
index 539e588c..99a36d3c 100644
--- a/package.json
+++ b/package.json
@@ -11,15 +11,15 @@
   },
   "scripts": {
     "lint": "eslint lib/**/*.js test/**/*.js",
-    "test": "npm run test:new && npm run test:server && npm run test:browser && npm run test:features",
-    "test:new": "mocha \"lib/api/test/**/*.test.js\"",
+    "test": "npm run test:next && npm run test:server && npm run test:browser && npm run test:features",
+    "test:next": "mocha \"lib/next/test/**/*.test.js\"",
     "test:server": "mocha \"test/unit/**/*-test.js\"",
     "test:server:coverage": "nyc npm run test:server",
     "test:browser": "mochify \"test/unit/**/*.js\"",
     "test:features": "node scripts/cucumber.js",
     "coveralls": "nyc --reporter=text-lcov npm run test:server | coveralls",
     "ci:lint": "npm run lint",
-    "ci:test": "npm run coveralls && npm run test:new && npm run test:browser && npm run test:features",
+    "ci:test": "npm run coveralls && npm run test:next && npm run test:browser && npm run test:features",
     "ci:release": "semantic-release",
     "precommit": "lint-staged"
   },