diff --git a/lib/src/issue_tracker/client.dart b/lib/src/issue_tracker/client.dart
index 997a964..5ed1bad 100644
--- a/lib/src/issue_tracker/client.dart
+++ b/lib/src/issue_tracker/client.dart
@@ -745,9 +745,9 @@ class IssueTrackerClient {
             if (body != null) {
               request.headers.set(
                 HttpHeaders.contentTypeHeader,
-                'application/json',
+                'application/json; charset=utf-8',
               );
-              request.write(jsonEncode(body));
+              request.add(utf8.encode(jsonEncode(body)));
             }
             final response = await request.close();
             final responseBody = await utf8.decodeStream(response);
@@ -833,7 +833,7 @@ class IssueTrackerClient {
         'Basic ${base64Encode(utf8.encode('apikey:${config.token}'))}',
       );
       if (body != null) {
-        request.write(jsonEncode(body));
+        request.add(utf8.encode(jsonEncode(body)));
       }
 
       final response = await request.close();
diff --git a/lib/src/notifier/notifier.dart b/lib/src/notifier/notifier.dart
index 7f9ec76..6a3d1dc 100644
--- a/lib/src/notifier/notifier.dart
+++ b/lib/src/notifier/notifier.dart
@@ -125,17 +125,19 @@ class DiscordWebhookNotifier implements Notifier {
     final uri = Uri.parse(webhookUrl);
     final request = await _httpClient.postUrl(uri);
     request.headers.contentType = ContentType.json;
-    request.write(
-      jsonEncode({
-        'content': formatDiscordNotificationMessage(
-          event: event,
-          context: context,
-        ),
-        if (config.username != null && config.username!.isNotEmpty)
-          'username': config.username,
-        if (config.avatarUrl != null && config.avatarUrl!.isNotEmpty)
-          'avatar_url': config.avatarUrl,
-      }),
+    request.add(
+      utf8.encode(
+        jsonEncode({
+          'content': formatDiscordNotificationMessage(
+            event: event,
+            context: context,
+          ),
+          if (config.username != null && config.username!.isNotEmpty)
+            'username': config.username,
+          if (config.avatarUrl != null && config.avatarUrl!.isNotEmpty)
+            'avatar_url': config.avatarUrl,
+        }),
+      ),
     );
 
     final response = await request.close();
diff --git a/skills-lock.json b/skills-lock.json
index e2fd9df..6dcd056 100644
--- a/skills-lock.json
+++ b/skills-lock.json
@@ -944,7 +944,7 @@
     "worktrunk": {
       "source": "max-sixty/worktrunk",
       "sourceType": "github",
-      "computedHash": "252c02ad30d62a966f6eff331be0b440c058bb346462b8ef0dab276c9ea2abbc"
+      "computedHash": "7123a4ec54e86c85723f1fdfb0bc1ea338e3f54078aafb791bb6fe12987022e7"
     },
     "write-coding-standards-from-file": {
       "source": "github/awesome-copilot",
diff --git a/test/support/fake_gh.dart b/test/support/fake_gh.dart
index 38ab70a..6603d52 100644
--- a/test/support/fake_gh.dart
+++ b/test/support/fake_gh.dart
@@ -363,7 +363,7 @@ Future<void> _postGitHubWebhook(
     final request = await client.postUrl(Uri.parse(targetUrl));
     request.headers.contentType = ContentType.json;
     request.headers.set('X-GitHub-Event', 'issue_comment');
-    request.write(jsonEncode(webhookPayload));
+    request.add(utf8.encode(jsonEncode(webhookPayload)));
     await request.close();
   } finally {
     client.close(force: true);
diff --git a/test/support/fake_gosmee.dart b/test/support/fake_gosmee.dart
index e0ba83d..c30d058 100644
--- a/test/support/fake_gosmee.dart
+++ b/test/support/fake_gosmee.dart
@@ -78,7 +78,7 @@ Future<void> _postWebhook(
     final request = await client.postUrl(Uri.parse(targetUrl));
     request.headers.contentType = ContentType.json;
     request.headers.set(webhookHeader, 'issue_comment');
-    request.write(jsonEncode(payload));
+    request.add(utf8.encode(jsonEncode(payload)));
     await request.close();
   } finally {
     client.close(force: true);