Systems

The "systems" lens covers internal building blocks that span every Bitwarden service. They live mostly in src/Core/Platform/, src/Core/Services/, src/Core/Settings/, src/Core/Utilities/, plus src/Infrastructure.Dapper/ and src/Infrastructure.EntityFramework/. Each system is reused by every app: the API talks to the same database layer the Admin host does; both use the same mail service, push service, application cache, and feature flags.

The pages in this section:

• Data infrastructure — the dual Dapper / EF Core repository pattern, the SQL Server Database Project, and the per-provider migration sets.
• IdentityServer & auth pipeline — Bitwarden's wiring of Duende IdentityServer, custom grants, persisted-grant store, and the user / role stores backing ASP.NET Core Identity.
• Push & SignalR — the IPushNotificationService abstraction and the multi-provider push pipeline (SignalR via the Notifications host, Azure Notification Hub, relay-mode for self-host).
• Mail (Handlebars/MJML) — the in-process mail rendering pipeline, MJML/Handlebars templates per team, and the SMTP / SendGrid / Mailgun / NoOp delivery backends.
• Jobs & scheduling (Quartz.NET) — how each app registers periodic Quartz jobs through JobsHostedService, the canonical job categories, and self-host vs. cloud differences.
• Event integrations — Slack, Teams, webhook, HEC, Datadog, etc. plumbing in src/Core/AdminConsole/Services/Implementations/EventIntegrations/.
• Configuration & secrets — GlobalSettings binding from appsettings.*.json, env vars, user-secrets, Azure Key Vault, and the Setup utility on self-host.
• Application cache — the per-host IApplicationCacheService plus the Service Bus topic that invalidates it cluster-wide.
• Feature flags — the LaunchDarkly-backed IFeatureService and how to add a flag.
• Tokenable & data protection — Bitwarden's signed-payload Tokenable<T> base type and the ASP.NET Core data-protection setup (Azure Blob persistence in cloud).

These pages link out to feature pages where the system shows up in real flows.