diff --git a/src/config.ts b/src/config.ts
index f80e5eed..1dd688b7 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -69,7 +69,7 @@ class Conf {
   }
   /** Get a link to a nip19-encoded entity in the configured external viewer. */
   static external(path: string) {
-    return new URL(path, Conf.externalDomain);
+    return new URL(path, Conf.externalDomain).toString();
   }
   /**
    * Heroku-style database URL. This is used in production to connect to the
diff --git a/src/entities/MastodonAccount.ts b/src/entities/MastodonAccount.ts
index 4873ed4c..a7fef5de 100644
--- a/src/entities/MastodonAccount.ts
+++ b/src/entities/MastodonAccount.ts
@@ -40,7 +40,7 @@ export interface MastodonAccount {
   username: string;
   ditto: {
     accepts_zaps: boolean;
-    external?: URL;
+    external_url: string;
   };
   pleroma: {
     deactivated: boolean;
diff --git a/src/entities/MastodonStatus.ts b/src/entities/MastodonStatus.ts
index 430f8e7f..20c52438 100644
--- a/src/entities/MastodonStatus.ts
+++ b/src/entities/MastodonStatus.ts
@@ -40,6 +40,6 @@ export interface MastodonStatus {
     quotes_count: number;
   };
   ditto: {
-    external?: URL;
+    external_url: string;
   };
 }
diff --git a/src/views/mastodon/accounts.ts b/src/views/mastodon/accounts.ts
index 4217f699..5abb1aca 100644
--- a/src/views/mastodon/accounts.ts
+++ b/src/views/mastodon/accounts.ts
@@ -82,7 +82,7 @@ async function renderAccount(
     username: parsed05?.nickname || npub.substring(0, 8),
     ditto: {
       accepts_zaps: Boolean(getLnurl({ lud06, lud16 })),
-      external: Conf.externalDomain === Conf.localDomain ? undefined : Conf.external(npub),
+      external_url: Conf.external(npub),
     },
     pleroma: {
       deactivated: names.has('disabled'),
diff --git a/src/views/mastodon/statuses.ts b/src/views/mastodon/statuses.ts
index 7ac9c07a..2fa8f313 100644
--- a/src/views/mastodon/statuses.ts
+++ b/src/views/mastodon/statuses.ts
@@ -125,7 +125,7 @@ async function renderStatus(event: DittoEvent, opts: RenderStatusOpts): Promise<
     url: Conf.local(`/${note}`),
     zapped: Boolean(zapEvent),
     ditto: {
-      external: Conf.externalDomain === Conf.localDomain ? undefined : Conf.external(note),
+      external_url: Conf.external(note),
     },
     pleroma: {
       emoji_reactions: reactions,