diff --git a/src/hooks.ts b/src/hooks.ts
index 9d217b3f..344e62a2 100644
--- a/src/hooks.ts
+++ b/src/hooks.ts
@@ -75,26 +75,31 @@ export const useOpenIDConfigNotLoaded = (): boolean => {
   return openIdConfigHasAttempted === false || openIdConfigFetching;
 };
 
-export const useJsonSchemaValidator = (schema: SchemaObject, acceptFalsyValue: boolean) => {
-  const ajv = useMemo(() => new Ajv(), []);
+export const useJsonSchemaValidator = (schema: SchemaObject, schemaName: string, acceptFalsyValue: boolean) => {
+  const ajv = useMemo(() => {
+    if (schema) {
+      // for schemas obtained by API: only instantiate Ajv when the schema is resolved
+      return new Ajv().addSchema(schema, schemaName);
+    }
+  }, [schema, schemaName]);
   return useCallback(
     (rule: unknown, value: unknown) => {
-      if (!schema) {
-        return Promise.reject(new Error("No JSON schema provided, cannot validate."));
+      const validator = ajv?.getSchema(schemaName);
+      if (!ajv || !validator) {
+        return Promise.reject(new Error(`No JSON schema provided for ${schemaName}, cannot validate.`));
       }
 
       if (!value && acceptFalsyValue) {
         return Promise.resolve();
       }
-      const valid = ajv.validate(schema, value);
 
-      if (valid) {
+      if (validator(value)) {
         return Promise.resolve();
       } else {
-        return Promise.reject(new Error(ajv.errorsText(ajv.errors)));
+        return Promise.reject(new Error(ajv.errorsText(validator.errors)));
       }
     },
-    [acceptFalsyValue, ajv, schema],
+    [acceptFalsyValue, ajv, schemaName],
   );
 };
 
@@ -104,5 +109,5 @@ export const useDatsValidator = () => {
   const datsSchema = {
     type: "object",
   };
-  return useJsonSchemaValidator(datsSchema, false);
+  return useJsonSchemaValidator(datsSchema, "dats", false);
 };
diff --git a/src/modules/metadata/hooks.js b/src/modules/metadata/hooks.js
index 5769e115..4c4c7f14 100644
--- a/src/modules/metadata/hooks.js
+++ b/src/modules/metadata/hooks.js
@@ -69,5 +69,5 @@ export const useDiscoverySchema = () => {
 
 export const useDiscoveryValidator = () => {
   const discoverySchema = useDiscoverySchema();
-  return useJsonSchemaValidator(discoverySchema, true);
+  return useJsonSchemaValidator(discoverySchema, "discovery", true);
 };