diff --git a/README.md b/README.md
index 753ac3f..ef72488 100644
--- a/README.md
+++ b/README.md
@@ -394,7 +394,8 @@ $browser
 Make assertions about json responses using [JMESPath expressions](https://jmespath.org/)
 See the [JMESPath Tutorials](https://jmespath.org/tutorial.html) to learn more.
 
-**NOTE:** `mtdowling/jmespath.php` is required: `composer require --dev mtdowling/jmespath.php`.
+> **Note**
+> `mtdowling/jmespath.php` is required: `composer require --dev mtdowling/jmespath.php`.
 
 ```php
 /** @var \Zenstruck\Browser\KernelBrowser $browser **/
@@ -437,6 +438,10 @@ $json = $browser
 ;
 ```
 
+> **Note**
+> See the [full `zenstruck/assert` expectation API documentation](https://github.com/zenstruck/assert#expectation-api)
+> to see all the methods available on `Zenstruck\Browser\Json`.
+
 ### PantherBrowser
 
 *The `PantherBrowser` is experimental in 1.0 and may be subject to BC Breaks.*
diff --git a/src/Browser/Json.php b/src/Browser/Json.php
index e8fd3bb..6b888cc 100644
--- a/src/Browser/Json.php
+++ b/src/Browser/Json.php
@@ -4,6 +4,7 @@
 
 use Zenstruck\Assert;
 use Zenstruck\Assert\Expectation;
+
 use function JmesPath\search;
 
 /**
@@ -15,6 +16,9 @@ final class Json
 {
     private string $source;
 
+    /** @var mixed */
+    private $decoded;
+
     public function __construct(string $source)
     {
         $this->source = $source;
@@ -125,11 +129,7 @@ public function search(string $selector)
      */
     public function decoded()
     {
-        if (empty($this->source)) {
-            return null;
-        }
-
-        return \json_decode($this->source, true, 512, \JSON_THROW_ON_ERROR);
+        return $this->decoded ??= empty($this->source) ? null : \json_decode($this->source, true, 512, \JSON_THROW_ON_ERROR);
     }
 
     /**
diff --git a/tests/KernelBrowserAuthenticationTest.php b/tests/KernelBrowserAuthenticationTest.php
index cbab613..665fc14 100644
--- a/tests/KernelBrowserAuthenticationTest.php
+++ b/tests/KernelBrowserAuthenticationTest.php
@@ -11,6 +11,7 @@
 use Zenstruck\Browser\Tests\Fixture\Kernel;
 use Zenstruck\Foundry\Configuration;
 use Zenstruck\Foundry\Factory;
+
 use function Zenstruck\Foundry\factory;
 
 /**