diff --git a/docs/Reference/Routes.md b/docs/Reference/Routes.md
index 018cc51301a..93567c1eb10 100644
--- a/docs/Reference/Routes.md
+++ b/docs/Reference/Routes.md
@@ -734,9 +734,10 @@ fastify.route({
 
 #### Asynchronous Custom Constraints
 
-You can provide your custom constraints and the `constraint` criteria can be fetch
-from other source, for example `database`. Usage of asynchronous custom constraint
-should place at the last resort since it impacts the router performance.
+You can provide your custom constraints and the `constraint` criteria can be
+fetched from other source, for example `database`. Usage of asynchronous custom
+constraint should place at the last resort since it impacts the router
+performance.
 
 ```js
 function databaseOperation(field, done) {
@@ -767,7 +768,7 @@ const secret = {
 > When using with asynchronous constraint. It is highly recommend never return error
 > inside the callback. If the error is not preventable, it is recommended to provide
 > a custom `frameworkErrors` handler to deal with it. Otherwise, you route selection
-> may broken or expose sensitive information to hacker.
+> may break or expose sensitive information to attackers.
 > 
 > ```js
 > const fastify = require('fastify')({
diff --git a/fastify.js b/fastify.js
index a4669d0ec74..47619473128 100644
--- a/fastify.js
+++ b/fastify.js
@@ -749,9 +749,7 @@ function fastify (options) {
     return function preRouting (req, res) {
       // only call isAsyncConstraint once
       if (isAsync === undefined) isAsync = router.isAsyncConstraint()
-      if (!rewriteUrl) {
-        router.routing(req, res, buildAsyncConstraintCallback(isAsync, req, res))
-      } else {
+      if (rewriteUrl) {
         const originalUrl = req.url
         const url = rewriteUrl(req)
         if (originalUrl !== url) {
@@ -762,8 +760,8 @@ function fastify (options) {
             req.destroy(new Error(`Rewrite url for "${req.url}" needs to be of type "string" but received "${typeof url}"`))
           }
         }
-        router.routing(req, res, buildAsyncConstraintCallback(isAsync, req, res))
       }
+      router.routing(req, res, buildAsyncConstraintCallback(isAsync, req, res))
     }
   }
 }