diff --git a/packages/builder/src/helpers/urlStateSync.js b/packages/builder/src/helpers/urlStateSync.js
index 7b33caf042..cbe4ad0e4a 100644
--- a/packages/builder/src/helpers/urlStateSync.js
+++ b/packages/builder/src/helpers/urlStateSync.js
@@ -1,22 +1,45 @@
 import { get } from "svelte/store"
+import { isChangingPage } from "@roxi/routify"
 
 export const syncURLToState = options => {
-  const { keys, params, store, goto } = options || {}
+  const { keys, params, store, goto, redirect } = options || {}
   if (
     !keys?.length ||
     !params?.subscribe ||
     !store?.subscribe ||
-    !goto?.subscribe
+    !goto?.subscribe ||
+    !redirect?.subscribe
   ) {
+    console.warn("syncURLToState invoked with missing parameters")
     return
   }
 
-  // We can't dynamically fetch the value of routify stores so we need to
-  // just subscribe and cache the latest versions.
+  // We can't dynamically fetch the value of stateful routify stores so we need
+  // to just subscribe and cache the latest versions.
   // We can grab their initial values as this is during component
   // initialisation.
   let cachedParams = get(params)
   let cachedGoto = get(goto)
+  let cachedRedirect = get(redirect)
+  let hydrated = false
+
+  // Navigate to a certain URL
+  const gotoUrl = url => {
+    if (get(isChangingPage) && hydrated) {
+      return
+    }
+    console.log("Navigating to", url)
+    cachedGoto(url)
+  }
+
+  // Redirect to a certain URL
+  const redirectUrl = url => {
+    if (get(isChangingPage) && hydrated) {
+      return
+    }
+    console.log("Redirecting to", url)
+    cachedRedirect(url)
+  }
 
   // Updates state with new URL params
   const mapUrlToState = params => {
@@ -26,16 +49,27 @@ export const syncURLToState = options => {
     for (let key of keys) {
       const urlValue = params?.[key.url]
       const stateValue = state?.[key.state]
-      if (urlValue !== stateValue) {
+      if (urlValue && urlValue !== stateValue) {
         console.log(
           `state.${key.state} (${stateValue}) <= url.${key.url} (${urlValue})`
         )
         stateUpdates.push(state => {
           state[key.state] = urlValue
         })
+        if (key.validate && key.fallbackUrl) {
+          if (!key.validate(urlValue)) {
+            console.log("Invalid URL param!")
+            redirectUrl(key.fallbackUrl)
+            hydrated = true
+            return
+          }
+        }
       }
     }
 
+    // Mark our initial hydration as completed
+    hydrated = true
+
     // Avoid updating the store at all if not necessary to prevent a wasted
     // store invalidation
     if (!stateUpdates.length) {
@@ -62,10 +96,17 @@ export const syncURLToState = options => {
       const stateValue = state?.[key.state]
       url += `/${stateValue}`
       if (stateValue !== urlValue) {
+        needsUpdate = true
         console.log(
           `url.${key.url} (${urlValue}) <= state.${key.state} (${stateValue})`
         )
-        needsUpdate = true
+        if (key.validate && key.fallbackUrl) {
+          if (!key.validate(stateValue)) {
+            console.log("Invalid state param!")
+            redirectUrl(key.fallbackUrl)
+            return
+          }
+        }
       }
     }
 
@@ -76,8 +117,9 @@ export const syncURLToState = options => {
     }
 
     // Navigate to the new URL
-    console.log("Navigating to", url)
-    cachedGoto(url)
+    if (!get(isChangingPage)) {
+      gotoUrl(url)
+    }
   }
 
   // Initially hydrate state from URL
@@ -89,10 +131,13 @@ export const syncURLToState = options => {
     mapUrlToState($urlParams)
   })
 
-  // Subscribe to goto changes and cache them
+  // Subscribe to routify store changes and cache them
   const unsubscribeGoto = goto.subscribe($goto => {
     cachedGoto = $goto
   })
+  const unsubscribeRedirect = redirect.subscribe($redirect => {
+    cachedRedirect = $redirect
+  })
 
   // Subscribe to store changes and keep URL up to date
   const unsubscribeStore = store.subscribe(mapStateToUrl)
@@ -101,6 +146,7 @@ export const syncURLToState = options => {
   return () => {
     unsubscribeParams()
     unsubscribeGoto()
+    unsubscribeRedirect()
     unsubscribeStore()
   }
 }
diff --git a/packages/builder/src/pages/builder/app/[application]/design/[screenId]/_layout.svelte b/packages/builder/src/pages/builder/app/[application]/design/[screenId]/_layout.svelte
index 5a93854033..ad17c127b6 100644
--- a/packages/builder/src/pages/builder/app/[application]/design/[screenId]/_layout.svelte
+++ b/packages/builder/src/pages/builder/app/[application]/design/[screenId]/_layout.svelte
@@ -1,20 +1,24 @@
 <script>
   import { IconSideNav, IconSideNavItem } from "@budibase/bbui"
-  import { params, goto, isActive } from "@roxi/routify"
-  import { store } from "builderStore"
+  import { params, goto, redirect, isActive } from "@roxi/routify"
+  import { store, allScreens } from "builderStore"
   import { syncURLToState } from "helpers/urlStateSync"
   import { onDestroy } from "svelte"
 
+  // Keep URL and state in sync for selected screen ID
   const unsync = syncURLToState({
     keys: [
       {
         url: "screenId",
         state: "selectedScreenId",
+        validate: screenId => $allScreens.some(x => x._id === screenId),
+        fallbackUrl: "../",
       },
     ],
     store,
     params,
     goto,
+    redirect,
   })
 
   onDestroy(unsync)