diff --git a/modules/reitit-schema/src/reitit/coercion/schema.cljc b/modules/reitit-schema/src/reitit/coercion/schema.cljc
index 022f3872..baf9e309 100644
--- a/modules/reitit-schema/src/reitit/coercion/schema.cljc
+++ b/modules/reitit-schema/src/reitit/coercion/schema.cljc
@@ -26,11 +26,11 @@
    (fn [x]
      (cond
        #?@(:clj [(class? x) (.getName ^Class x)])
-       (instance? schema.core.OptionalKey x) (pr-str (list 'opt (:k x)))
-       (instance? schema.core.RequiredKey x) (pr-str (list 'req (:k x)))
+       (instance? #?(:clj schema.core.OptionalKey :cljs s/OptionalKey) x) (pr-str (list 'opt (:k x)))
+       (instance? #?(:clj schema.core.RequiredKey :cljs s/RequiredKey) x) (pr-str (list 'req (:k x)))
        (and (satisfies? s/Schema x) (record? x)) (try (pr-str (s/explain x)) (catch #?(:clj Exception :cljs js/Error) _ x))
-       (instance? schema.utils.ValidationError x) (str (su/validation-error-explain x))
-       (instance? schema.utils.NamedError x) (str (su/named-error-explain x))
+       (instance? #?(:clj schema.utils.ValidationError :cljs su/ValidationError) x) (str (su/validation-error-explain x))
+       (instance? #?(:clj schema.utils.NamedError :cljs su/NamedError) x) (str (su/named-error-explain x))
        :else x))
    schema))
 
diff --git a/test/cljc/reitit/coercion_test.cljc b/test/cljc/reitit/coercion_test.cljc
index 97ab0aae..2e5a9e9d 100644
--- a/test/cljc/reitit/coercion_test.cljc
+++ b/test/cljc/reitit/coercion_test.cljc
@@ -7,6 +7,7 @@
             [reitit.coercion.spec]
             [reitit.core :as r]
             [schema.core :as s]
+            [schema.utils :as su]
             [spec-tools.data-spec :as ds])
   #?(:clj
      (:import (clojure.lang ExceptionInfo))))
@@ -106,3 +107,19 @@
                 {:compile coercion/compile-request-coercers})]
     (is (= {:path {:user-id 123, :company "metosin"}}
            (:parameters (match-by-path-and-coerce! router "/metosin/users/123"))))))
+
+(deftest schema-stringify-test
+  (is (= {"(opt :foo)" #?(:clj "java.lang.String" :cljs "Str")
+          "(req \"bar\")" #?(:clj "java.lang.String" :cljs "Str")}
+         (reitit.coercion.schema/stringify
+           {(s/optional-key :foo) s/Str
+            (s/required-key "bar") s/Str})))
+
+  (is (= "(named \"error-object\" \"name\")"
+         (reitit.coercion.schema/stringify
+           (new #?(:clj schema.utils.NamedError :cljs su/NamedError) "name" "error-object"))))
+
+  (is (= "(not :foo)"
+         (reitit.coercion.schema/stringify
+           (new #?(:clj schema.utils.ValidationError :cljs su/ValidationError)
+                nil nil (delay :foo) nil)))))