diff --git a/README.md b/README.md
index ffb4024..a9b3321 100644
--- a/README.md
+++ b/README.md
@@ -235,7 +235,8 @@ Options include:
   imports,
   resolutions,
   builtins,
-  conditions
+  conditions,
+  attributes
 }
 ```
 
diff --git a/index.js b/index.js
index 42d63e9..96507c5 100644
--- a/index.js
+++ b/index.js
@@ -112,6 +112,10 @@ const Module = module.exports = exports = class Module {
     Module._modules.delete(this)
   }
 
+  _run () {
+    binding.runModule(this._handle, Module._handle, Module._onrun)
+  }
+
   _transform (isImport, isDynamicImport) {
     if (isDynamicImport) {
       this._synthesize()
@@ -183,10 +187,6 @@ const Module = module.exports = exports = class Module {
     this._handle = binding.createSyntheticModule(this._url.href, this._names, Module._handle)
   }
 
-  _run () {
-    binding.runModule(this._handle, Module._handle, Module._onrun)
-  }
-
   _evaluate (eagerRun = false) {
     if ((this._state & constants.states.EVALUATED) !== 0) return
 
@@ -208,16 +208,12 @@ const Module = module.exports = exports = class Module {
       )
 
       if (eagerRun) this._run()
-    }
-
-    if (this._type === constants.types.MODULE) {
+    } else if (this._type === constants.types.MODULE) {
       this._run()
 
       this._exports = binding.getNamespace(this._handle)
-    }
-
-    if (this._type === constants.types.ADDON) {
-      if (eagerRun) this._run()
+    } else if (eagerRun) {
+      this._run()
     }
   }
 
@@ -245,7 +241,7 @@ const Module = module.exports = exports = class Module {
 
   static _handle = binding.init(this, this._onimport, this._onevaluate, this._onmeta)
 
-  static _onimport (href, assertions, referrerHref, isDynamicImport) {
+  static _onimport (href, attributes, referrerHref, isDynamicImport) {
     const referrer = this._cache[referrerHref] || null
 
     if (referrer === null) {
@@ -256,28 +252,9 @@ const Module = module.exports = exports = class Module {
       throw errors.MODULE_NOT_FOUND(msg)
     }
 
-    const url = this.resolve(href, referrer._url, {
-      isImport: true,
-      referrer
-    })
-
-    let type
+    const url = this.resolve(href, referrer._url, { isImport: true, referrer })
 
-    switch (assertions.type) {
-      case 'module':
-        type = constants.types.MODULE
-        break
-      case 'json':
-        type = constants.types.JSON
-        break
-    }
-
-    const module = this.load(url, {
-      isImport: true,
-      isDynamicImport,
-      referrer,
-      type
-    })
+    const module = this.load(url, { isImport: true, isDynamicImport, referrer, attributes })
 
     return module._handle
   }
@@ -383,7 +360,8 @@ const Module = module.exports = exports = class Module {
       isDynamicImport = false,
 
       referrer = null,
-      type = 0,
+      attributes,
+      type = typeForAttributes(attributes),
       defaultType = referrer ? referrer._defaultType : 0,
       cache = referrer ? referrer._cache : self._cache,
       main = referrer ? referrer._main : null,
@@ -414,10 +392,10 @@ const Module = module.exports = exports = class Module {
           module._builtins = builtins
           module._conditions = conditions
 
-          let extension = self._extensionFor(type) || path.extname(url.pathname)
+          let extension = extensionForType(type) || path.extname(url.pathname)
 
           if (extension in self._extensions === false) {
-            if (defaultType) extension = self._extensionFor(defaultType) || '.js'
+            if (defaultType) extension = extensionForType(defaultType) || '.js'
             else extension = '.js'
           }
 
@@ -537,22 +515,41 @@ const Module = module.exports = exports = class Module {
       return null
     }
   }
+}
+
+function extensionForType (type) {
+  switch (type) {
+    case constants.types.SCRIPT:
+      return '.cjs'
+    case constants.types.MODULE:
+      return '.esm'
+    case constants.types.JSON:
+      return '.json'
+    case constants.types.BUNDLE:
+      return '.bundle'
+    case constants.types.ADDON:
+      return '.bare'
+    default:
+      return null
+  }
+}
 
-  static _extensionFor (type) {
-    switch (type) {
-      case constants.types.SCRIPT:
-        return '.cjs'
-      case constants.types.MODULE:
-        return '.esm'
-      case constants.types.JSON:
-        return '.json'
-      case constants.types.BUNDLE:
-        return '.bundle'
-      case constants.types.ADDON:
-        return '.bare'
-      default:
-        return null
-    }
+function typeForAttributes (attributes) {
+  if (typeof attributes !== 'object' || attributes === null) return 0
+
+  switch (attributes.type) {
+    case 'script':
+      return constants.types.SCRIPT
+    case 'module':
+      return constants.types.MODULE
+    case 'json':
+      return constants.types.JSON
+    case 'bundle':
+      return constants.types.BUNDLE
+    case 'addon':
+      return constants.types.ADDON
+    default:
+      return 0
   }
 }
 
@@ -613,10 +610,10 @@ const createRequire = exports.createRequire = function createRequire (parentURL,
 
   return require
 
-  function require (specifier) {
+  function require (specifier, opts = {}) {
     const resolved = self.resolve(specifier, referrer._url, { referrer })
 
-    const module = self.load(resolved, { referrer })
+    const module = self.load(resolved, { referrer, attributes: opts.with })
 
     return module._exports
   }
diff --git a/test.js b/test.js
index 8688920..267c6e3 100644
--- a/test.js
+++ b/test.js
@@ -1416,7 +1416,7 @@ test('import.meta', (t) => {
   t.comment(meta.addon.host)
 })
 
-test('import assertions', (t) => {
+test('import attributes', (t) => {
   t.teardown(onteardown)
 
   const protocol = new Module.Protocol({
@@ -1440,6 +1440,54 @@ test('import assertions', (t) => {
   t.alike(Module.load(new URL(root + '/foo.mjs'), { protocol }).exports.default, { hello: 'world' })
 })
 
+test('dynamic import attributes', async (t) => {
+  t.teardown(onteardown)
+
+  const protocol = new Module.Protocol({
+    exists (url) {
+      return url.href === root + '/bar'
+    },
+
+    read (url) {
+      if (url.href === root + '/foo.mjs') {
+        return 'export default import(\'/bar\', { with: { type: \'json\' } })'
+      }
+
+      if (url.href === root + '/bar') {
+        return '{ "hello": "world" }'
+      }
+
+      t.fail()
+    }
+  })
+
+  t.comment(await Module.load(new URL(root + '/foo.mjs'), { protocol }).exports.default)
+})
+
+test('require attributes', (t) => {
+  t.teardown(onteardown)
+
+  const protocol = new Module.Protocol({
+    exists (url) {
+      return url.href === root + '/bar'
+    },
+
+    read (url) {
+      if (url.href === root + '/foo.js') {
+        return 'module.exports = require(\'/bar\', { with: { type: \'json\' } })'
+      }
+
+      if (url.href === root + '/bar') {
+        return '{ "hello": "world" }'
+      }
+
+      t.fail()
+    }
+  })
+
+  t.alike(Module.load(new URL(root + '/foo.js'), { protocol }).exports, { hello: 'world' })
+})
+
 test('createRequire', (t) => {
   t.teardown(onteardown)