diff --git a/docs/architecture/c4/l1-context.puml b/docs/architecture/c4/l1-context.puml
index 8d2efb8f..d31ae49f 100644
--- a/docs/architecture/c4/l1-context.puml
+++ b/docs/architecture/c4/l1-context.puml
@@ -8,9 +8,11 @@ Person(member, "Family Member", "Access by administrator invite. Searches, brows
 
 System(familienarchiv, "Familienarchiv", "Web application for digitising, organising, and searching family documents")
 System_Ext(mail, "Email Service", "SMTP server. Delivers notification emails (mentions, replies) and password-reset links.")
+System_Ext(glitchtip, "GlitchTip", "Self-hosted error tracking (Sentry-compatible). Receives frontend and backend error events with stack traces.")
 
 Rel(admin, familienarchiv, "Manages via browser", "HTTPS")
 Rel(member, familienarchiv, "Searches, reads, and transcribes via browser", "HTTPS")
 Rel(familienarchiv, mail, "Sends notification and password-reset emails (optional)", "SMTP")
+Rel(familienarchiv, glitchtip, "Sends error events with errorId and stack trace", "HTTPS")
 
 @enduml