diff --git a/packages/platform/src/Url.ts b/packages/platform/src/Url.ts
index bb9304536e8..97995d1479a 100644
--- a/packages/platform/src/Url.ts
+++ b/packages/platform/src/Url.ts
@@ -257,7 +257,7 @@ export const setUrlParams: {
   (url: URL, urlParams: UrlParams.UrlParams): URL
 } = dual(2, (url: URL, searchParams: UrlParams.UrlParams) =>
   mutate(url, (url) => {
-    url.search = UrlParams.toString(searchParams)
+    url.search = UrlParams.toPercentEncoded(searchParams)
   }))
 
 /**
@@ -320,5 +320,5 @@ export const modifyUrlParams: {
 } = dual(2, (url: URL, f: (urlParams: UrlParams.UrlParams) => UrlParams.UrlParams) =>
   mutate(url, (url) => {
     const params = f(UrlParams.fromInput(url.searchParams))
-    url.search = UrlParams.toString(params)
+    url.search = UrlParams.toPercentEncoded(params)
   }))
diff --git a/packages/platform/src/UrlParams.ts b/packages/platform/src/UrlParams.ts
index 0ca908180f8..25567eb5072 100644
--- a/packages/platform/src/UrlParams.ts
+++ b/packages/platform/src/UrlParams.ts
@@ -229,6 +229,15 @@ export const makeUrl = (url: string, params: UrlParams, hash: Option.Option<stri
  */
 export const toString = (self: UrlParams): string => new URLSearchParams(self as any).toString()
 
+/**
+ * @since 1.0.0
+ * @category conversions
+ */
+export const toPercentEncoded = (self: UrlParams): string =>
+  self.map(([key, value]) =>
+    `${encodeURIComponent(key)}=${encodeURIComponent(value)}`
+  ).join("&")
+
 const baseUrl = (): string | undefined => {
   if (
     "location" in globalThis &&