diff --git a/src/core/json/include/sourcemeta/core/json_object.h b/src/core/json/include/sourcemeta/core/json_object.h
index 48dbdda5b..b680d8bbe 100644
--- a/src/core/json/include/sourcemeta/core/json_object.h
+++ b/src/core/json/include/sourcemeta/core/json_object.h
@@ -37,6 +37,28 @@ template <typename Key, typename Value, typename Hash> class JSONObject {
     key_type first;
     mapped_type second;
     hash_type hash;
+
+    /// Check whether this entry's key equals the given key, comparing the
+    /// precomputed hashes first and only falling back to a string comparison
+    /// when the hash is not perfect. For example:
+    ///
+    /// ```cpp
+    /// #include <sourcemeta/core/json.h>
+    /// #include <cassert>
+    ///
+    /// const sourcemeta::core::JSON document =
+    ///   sourcemeta::core::parse_json("{ \"foo\": 1 }");
+    /// const auto &entry{*document.as_object().cbegin()};
+    /// assert(entry.key_equals(
+    ///   "foo", sourcemeta::core::JSON::Object::hash("foo")));
+    /// ```
+    [[nodiscard]] inline auto key_equals(const KeyView key,
+                                         const hash_type key_hash) const
+        -> bool {
+      assert(JSONObject::hash(key) == key_hash);
+      return this->hash == key_hash &&
+             (hasher.is_perfect(key_hash) || this->first == key);
+    }
   };
 
   using underlying_type = std::vector<Entry>;
diff --git a/test/json/json_object_test.cc b/test/json/json_object_test.cc
index 0d1ab0a78..b51709d5f 100644
--- a/test/json/json_object_test.cc
+++ b/test/json/json_object_test.cc
@@ -1478,3 +1478,39 @@ TEST(JSON_object, assign_if_missing_with_string_view) {
   EXPECT_EQ(document.at("foo").to_integer(), 1);
   EXPECT_EQ(document.at("bar").to_integer(), 2);
 }
+
+TEST(JSON_object, entry_key_equals_perfect_match) {
+  const auto document{sourcemeta::core::parse_json(R"({ "foo": 1 })")};
+  const auto &entry{*document.as_object().cbegin()};
+  EXPECT_TRUE(
+      entry.key_equals("foo", sourcemeta::core::JSON::Object::hash("foo")));
+}
+
+TEST(JSON_object, entry_key_equals_perfect_mismatch) {
+  const auto document{sourcemeta::core::parse_json(R"({ "foo": 1 })")};
+  const auto &entry{*document.as_object().cbegin()};
+  EXPECT_FALSE(
+      entry.key_equals("bar", sourcemeta::core::JSON::Object::hash("bar")));
+}
+
+TEST(JSON_object, entry_key_equals_imperfect_match) {
+  const std::string key(40, 'a');
+  sourcemeta::core::JSON document{sourcemeta::core::JSON::make_object()};
+  document.assign(key, sourcemeta::core::JSON{1});
+  const auto &entry{*document.as_object().cbegin()};
+  EXPECT_FALSE(document.as_object().hash(key) ==
+               sourcemeta::core::JSON::Object::hash("a"));
+  EXPECT_TRUE(entry.key_equals(key, sourcemeta::core::JSON::Object::hash(key)));
+}
+
+TEST(JSON_object, entry_key_equals_imperfect_collision_is_rejected) {
+  const std::string stored{std::string(31, 'a') + "11111110" + "z"};
+  const std::string other{std::string(31, 'a') + "22222220" + "z"};
+  sourcemeta::core::JSON document{sourcemeta::core::JSON::make_object()};
+  document.assign(stored, sourcemeta::core::JSON{1});
+  const auto &entry{*document.as_object().cbegin()};
+  EXPECT_EQ(sourcemeta::core::JSON::Object::hash(stored),
+            sourcemeta::core::JSON::Object::hash(other));
+  EXPECT_FALSE(
+      entry.key_equals(other, sourcemeta::core::JSON::Object::hash(other)));
+}