diff --git a/resources/sql/autopatches/20251024.herald.webhookuri.sql b/resources/sql/autopatches/20251024.herald.webhookuri.sql
new file mode 100644
index 0000000000..df60f1aae6
--- /dev/null
+++ b/resources/sql/autopatches/20251024.herald.webhookuri.sql
@@ -0,0 +1,2 @@
+ALTER TABLE {$NAMESPACE}_herald.herald_webhook
+  MODIFY COLUMN webhookURI LONGTEXT NOT NULL;
diff --git a/src/applications/herald/storage/HeraldWebhook.php b/src/applications/herald/storage/HeraldWebhook.php
index 0101dbef52..fd71980185 100644
--- a/src/applications/herald/storage/HeraldWebhook.php
+++ b/src/applications/herald/storage/HeraldWebhook.php
@@ -24,7 +24,7 @@ final class HeraldWebhook
       self::CONFIG_AUX_PHID => true,
       self::CONFIG_COLUMN_SCHEMA => array(
         'name' => 'text128',
-        'webhookURI' => 'text255',
+        'webhookURI' => 'text',
         'status' => 'text32',
         'hmacKey' => 'text32',
       ),
diff --git a/src/applications/herald/xaction/HeraldWebhookURITransaction.php b/src/applications/herald/xaction/HeraldWebhookURITransaction.php
index e0162085cb..55c1cb69de 100644
--- a/src/applications/herald/xaction/HeraldWebhookURITransaction.php
+++ b/src/applications/herald/xaction/HeraldWebhookURITransaction.php
@@ -4,6 +4,7 @@ final class HeraldWebhookURITransaction
   extends HeraldWebhookTransactionType {
 
   const TRANSACTIONTYPE = 'uri';
+  private $webhookURIMaxLength = 2048;
 
   public function generateOldValue($object) {
     return $object->getWebhookURI();
@@ -40,17 +41,16 @@ final class HeraldWebhookURITransaction
       return $errors;
     }
 
-    $max_length = $object->getColumnMaximumByteLength('webhookURI');
     foreach ($xactions as $xaction) {
       $old_value = $this->generateOldValue($object);
       $new_value = $xaction->getNewValue();
 
       $new_length = strlen($new_value);
-      if ($new_length > $max_length) {
+      if ($new_length > $this->webhookURIMaxLength) {
         $errors[] = $this->newInvalidError(
           pht(
             'Webhook URIs can be no longer than %s characters.',
-            new PhutilNumber($max_length)),
+            new PhutilNumber($this->webhookURIMaxLength)),
           $xaction);
       }