Architecture

How It Works

Spotlight consists of two components bundled in @spotlightjs/spotlight:

1. Sidecar Server - A local HTTP server that receives telemetry from your application and streams it to connected clients using Server-Sent Events (SSE).

2. UI - A React application that displays telemetry data in real-time. Available as a Desktop App or browser-based UI at localhost:8969.

Data Flow

Your App → Sentry SDK → Sidecar (port 8969) → UI
                              ↓
                        [In-memory store]
                              ↓
                    Desktop App / Browser / MCP

1. Your application sends telemetry via Sentry SDK
2. Sidecar receives and stores events in memory
3. Connected clients (UI, MCP) receive events via SSE
4. Events are displayed in real-time

Multiple Clients

A single sidecar can serve multiple clients simultaneously:

• Desktop App - Dedicated window with built-in UI
• Browser - Web UI at http://localhost:8969
• CLI - Stream events to terminal with spotlight tail
• MCP - AI assistants query events via Model Context Protocol

Learn More

Getting Started Install and configure Spotlight

Sidecar Details Configuration and SDK integration