---
type: guide
title: Scoreboard Stream
description: How live solves are broadcast to the SPA over Server-Sent Events.
tags: [guide, scoreboard, sse, stream]
timestamp: 2026-07-21T18:28:00Z
---

# Endpoint

`GET /api/v1/scoreboard/stream` (`@Sse()` handler in
`backend/src/modules/system/system.controller.ts`) opens an SSE stream
that pushes the public scoreboard projection every time a new solve is
recorded.

# Push path

1. The challenge solve path (admin validation, player submit) updates the
   `solve` table.
2. The same code path calls `SseHubService.publish('scoreboard', payload)`
   (`backend/src/common/services/sse-hub.service.ts`).
3. Every subscriber to `/api/v1/scoreboard/stream` receives the payload.

The hub is in-process; multi-replica deployments need a shared pub/sub
to fan out across pods (not in scope for this repo).

# Frontend consumer

The authenticated SPA shell subscribes on mount and updates the scoreboard
view whenever a new event arrives. The exact rendering lives inside the
authenticated shell's scoreboard component (see
[Frontend Structure](/architecture/frontend-structure.md)).

# See also

- [Event Window](/guides/event-window.md)
- [System Endpoints](/api/system.md)