diff --git a/docs/src/app/mailing-list/route.ts b/docs/src/app/mailing-list/route.ts
index aed4d28dc..669a0dec5 100644
--- a/docs/src/app/mailing-list/route.ts
+++ b/docs/src/app/mailing-list/route.ts
@@ -23,7 +23,10 @@ export async function POST(req: Request): Promise<Response> {
     console.log(formData.getAll('tags'));
     const data = {
       email: formData.get('email'),
-      tags: [...formData.getAll('tags'), `source:keystatic.com${pathname}`],
+      tags: [
+        ...formData.getAll('tags'),
+        `source:keystatic.com${pathname}`.substring(0, 80),
+      ],
     };
 
     const buttondownResponse = await fetch(
diff --git a/docs/src/components/forms/mailing-list.tsx b/docs/src/components/forms/mailing-list.tsx
index 9ec4de9e0..072177e7c 100644
--- a/docs/src/components/forms/mailing-list.tsx
+++ b/docs/src/components/forms/mailing-list.tsx
@@ -37,7 +37,7 @@ export default function MailingListForm() {
               name="tags"
               id="mailing-list-keystatic"
               className="form-checkbox size-4 rounded text-black"
-              value="keystatic_list"
+              value="list:keystatic"
               defaultChecked
             />
             <label
@@ -53,7 +53,7 @@ export default function MailingListForm() {
               name="tags"
               id="mailing-list-thinkmill"
               className="form-checkbox size-4 rounded text-black"
-              value="thinkmill_list"
+              value="list:thinkmill"
             />
             <label
               className="text-sm text-sand-11"