diff --git a/packages/ditto/entities/MastodonAccount.ts b/packages/ditto/entities/MastodonAccount.ts
index eedaaa29..4ea6665b 100644
--- a/packages/ditto/entities/MastodonAccount.ts
+++ b/packages/ditto/entities/MastodonAccount.ts
@@ -49,6 +49,7 @@ export interface MastodonAccount {
       days: number;
       start: string | null;
       end: string | null;
+      expires: string | null;
     };
   };
   domain?: string;
diff --git a/packages/ditto/views/mastodon/accounts.ts b/packages/ditto/views/mastodon/accounts.ts
index c2cf41ca..d541e633 100644
--- a/packages/ditto/views/mastodon/accounts.ts
+++ b/packages/ditto/views/mastodon/accounts.ts
@@ -121,6 +121,7 @@ function renderAccount(event: Omit<DittoEvent, 'id' | 'sig'>, opts: ToAccountOpt
         days: streakDays,
         start: streakStart ? nostrDate(streakStart).toISOString() : null,
         end: streakEnd ? nostrDate(streakEnd).toISOString() : null,
+        expires: streakEnd ? nostrDate(streakEnd + streakWindow).toISOString() : null,
       },
     },
     domain: parsed05?.domain,