DefectDojo is an open-source application security posture management (ASPM) and vulnerability management platform. It ingests scan results from over 100 security tools (SAST, DAST, SCA, container, cloud, secrets, infrastructure) via a consistent parser interface, normalizes findings, deduplicates them, and tracks remediation workflows across engagements and products. The system is a Django monolith with a REST API (Django REST Framework), Celery async workers for imports, SLA enforcement, and JIRA/GitHub sync, PostgreSQL for persistence, and Valkey/Redis as the message broker. Key entry points include the Django admin UI, DRF API viewsets, and Celery task dispatchers. External dependencies are PostgreSQL, Redis/Valkey, and optional integrations with JIRA, Slack, Microsoft Teams, and SSO providers (LDAP, OAuth2, SAML). The repository includes a Pro edition layer with additional features (custom RBAC, audit logging, priority SLA) that coexist with the open-source core via feature flags and conditional imports. The codebase demonstrates strong engineering with a well-defined parser factory pattern, prefetch mixins for API efficiency, SSRF-safe HTTP clients, and a request-level caching system, though it carries some technical debt from an ongoing V3 location model migration and numerous deprecated endpoints slated for removal.