Sentry is a full-stack application for error monitoring, performance tracing, session replay, and observability. In production, it ingests events (errors, transactions, logs, replays, profiles) from SDKs via a Relay proxy, processes them through Kafka streams, and stores data in ClickHouse (Snuba) and PostgreSQL. It exposes a REST API (Django REST Framework) and a React frontend for dashboards, issue management, alerts, and AI-powered features (Seer). The architecture is a monolith with hybrid-cloud services: a control silo for global state, cell silos for regional data, and an API gateway. Key entry points include the Relay ingestion endpoint, the Django WSGI/ASGI server, and Celery task workers. External dependencies include PostgreSQL, ClickHouse, Kafka, Redis, and cloud providers (GCP, AWS). The codebase also includes a billing/subscription layer (getsentry) and extensive third-party integrations (Slack, GitHub, Jira, etc.).