diff --git a/app/Transformer/Api/Mastodon/v1/AccountTransformer.php b/app/Transformer/Api/Mastodon/v1/AccountTransformer.php
index b06d8ea56..12e003583 100644
--- a/app/Transformer/Api/Mastodon/v1/AccountTransformer.php
+++ b/app/Transformer/Api/Mastodon/v1/AccountTransformer.php
@@ -19,7 +19,7 @@ class AccountTransformer extends Fractal\TransformerAbstract
 			'acct' => $acct,
 			'display_name' => $profile->name,
 			'locked' => (bool) $profile->is_private,
-			'created_at' => $profile->created_at->format('c'),
+			'created_at' => $profile->created_at->toIso8601ZuluString(),
 			'followers_count' => $profile->followerCount(),
 			'following_count' => $profile->followingCount(),
 			'statuses_count' => (int) $profile->statusCount(),
diff --git a/app/Transformer/Api/Mastodon/v1/StatusTransformer.php b/app/Transformer/Api/Mastodon/v1/StatusTransformer.php
index 6ddaf468b..40b3f7ba8 100644
--- a/app/Transformer/Api/Mastodon/v1/StatusTransformer.php
+++ b/app/Transformer/Api/Mastodon/v1/StatusTransformer.php
@@ -25,7 +25,7 @@ class StatusTransformer extends Fractal\TransformerAbstract
             'in_reply_to_account_id'    => $status->in_reply_to_profile_id,
             'reblog'                    => null,
             'content'                   => $status->rendered ?? $status->caption,
-            'created_at'                => $status->created_at->format('c'),
+            'created_at'                => $status->created_at->toIso8601ZuluString(),
             'emojis'                    => [],
             'reblogs_count'             => $status->reblogs_count != 0 ? $status->reblogs_count: $status->shares()->count(),
             'favourites_count'          => $status->likes_count != 0 ? $status->likes_count: $status->likes()->count(),