diff --git a/qutebrowser/config/configdata.yml b/qutebrowser/config/configdata.yml
index 0a98a7b6e..ac0aea9d3 100644
--- a/qutebrowser/config/configdata.yml
+++ b/qutebrowser/config/configdata.yml
@@ -83,10 +83,10 @@ new_instance_open_target_window:
 
 searchengines:
   default:
-    # FIXME:conf what if the user deletes/renames DEFAULT?
     DEFAULT: https://duckduckgo.com/?q={}
   type:
     name: Dict
+    required_keys: ['DEFAULT']
     keytype: String
     valtype: SearchEngineUrl
   desc: >-
diff --git a/qutebrowser/config/configtypes.py b/qutebrowser/config/configtypes.py
index d8c689e28..8a93b2305 100644
--- a/qutebrowser/config/configtypes.py
+++ b/qutebrowser/config/configtypes.py
@@ -1030,7 +1030,8 @@ class Dict(BaseType):
 
     """A dictionary of values."""
 
-    def __init__(self, keytype, valtype, *, fixed_keys=None, none_ok=False):
+    def __init__(self, keytype, valtype, *, fixed_keys=None,
+                 required_keys=None, none_ok=False):
         super().__init__(none_ok)
         # If the keytype is not a string, we'll get problems with showing it as
         # json in to_str() as json converts keys to strings.
@@ -1038,12 +1039,17 @@ class Dict(BaseType):
         self.keytype = keytype
         self.valtype = valtype
         self.fixed_keys = fixed_keys
+        self.required_keys = required_keys
 
     def _validate_keys(self, value):
         if (self.fixed_keys is not None and
                 value.keys() != set(self.fixed_keys)):
             raise configexc.ValidationError(
                 value, "Expected keys {}".format(self.fixed_keys))
+        if (self.required_keys is not None and not
+                set(self.required_keys).issubset(value.keys())):
+            raise configexc.ValidationError(
+                value, "Required keys {}".format(self.required_keys))
 
     def _none_value(self, value=None):
         """Return the value to be used when the setting is None.
diff --git a/tests/helpers/test_helper_utils.py b/tests/helpers/test_helper_utils.py
index d7eadb894..a783d98f8 100644
--- a/tests/helpers/test_helper_utils.py
+++ b/tests/helpers/test_helper_utils.py
@@ -73,3 +73,8 @@ def test_partial_compare_not_equal(val1, val2, error):
 ])
 def test_pattern_match(pattern, value, expected):
     assert utils.pattern_match(pattern=pattern, value=value) == expected
+
+
+def test_nop_contextmanager():
+    with utils.nop_contextmanager():
+        pass
diff --git a/tests/helpers/utils.py b/tests/helpers/utils.py
index 7dbd7dd25..e6e3d37c8 100644
--- a/tests/helpers/utils.py
+++ b/tests/helpers/utils.py
@@ -23,6 +23,7 @@
 import re
 import pprint
 import os.path
+import contextlib
 
 import pytest
 
@@ -170,3 +171,8 @@ def abs_datapath():
     """Get the absolute path to the end2end data directory."""
     file_abs = os.path.abspath(os.path.dirname(__file__))
     return os.path.join(file_abs, '..', 'end2end', 'data')
+
+
+@contextlib.contextmanager
+def nop_contextmanager():
+    yield
diff --git a/tests/unit/config/test_configtypes.py b/tests/unit/config/test_configtypes.py
index c34666a4b..64d05e7cd 100644
--- a/tests/unit/config/test_configtypes.py
+++ b/tests/unit/config/test_configtypes.py
@@ -40,6 +40,7 @@ from PyQt5.QtNetwork import QNetworkProxy
 from qutebrowser.config import configtypes, configexc
 from qutebrowser.utils import debug, utils, qtutils
 from qutebrowser.browser.network import pac
+from tests.helpers import utils as testutils
 
 
 class Font(QFont):
@@ -1390,16 +1391,35 @@ class TestDict:
                                valtype=configtypes.Int())
         assert typ.from_str('{"answer": 42}') == {"answer": 42}
 
-    @pytest.mark.parametrize('val', [
-        {"one": "1"},  # missing key
-        {"one": "1", "two": "2", "three": "3"},  # extra key
+    @pytest.mark.parametrize('kind, val, ok', [
+        ('fixed', {"one": "1"}, False),  # missing key
+        ('fixed', {"one": "1", "two": "2", "three": "3"}, False),  # extra key
+        ('fixed', {"one": "1", "two": "2"}, True),
+
+        ('required', {"one": "1"}, False),  # missing key
+        ('required', {"one": "1", "two": "2", "three": "3"}, True),  # extra
+        ('required', {"one": "1", "two": "2"}, True),
     ])
     @pytest.mark.parametrize('from_str', [True, False])
-    def test_fixed_keys(self, klass, val, from_str):
-        d = klass(keytype=configtypes.String(), valtype=configtypes.String(),
-                  fixed_keys=['one', 'two'])
+    def test_keys(self, klass, kind, val, ok, from_str):
+        if kind == 'fixed':
+            d = klass(keytype=configtypes.String(),
+                      valtype=configtypes.String(),
+                      fixed_keys=['one', 'two'])
+            message = 'Expected keys .*'
+        elif kind == 'required':
+            d = klass(keytype=configtypes.String(),
+                      valtype=configtypes.String(),
+                      required_keys=['one', 'two'])
+            message = 'Required keys .*'
 
-        with pytest.raises(configexc.ValidationError):
+        if ok:
+            expectation = testutils.nop_contextmanager()
+        else:
+            expectation = pytest.raises(configexc.ValidationError,
+                                        match=message)
+
+        with expectation:
             if from_str:
                 d.from_str(json.dumps(val))
             else: