Answer Overflow is a full-stack platform that indexes Discord community conversations and makes them publicly searchable via the web, Google, and AI assistants. It consists of a Discord bot (built with discord.js and Effect-TS) that syncs messages, threads, and channels into a Convex backend, and a Next.js web application that renders these conversations as rich, SEO-optimized pages with search, thread cards, user profiles, and an AI-powered chat assistant. The bot handles features like solution marking, auto-threading, forum guidelines consent, and sitemap generation. The web app supports multiple tenants (custom domains) and includes a dashboard for server management, analytics, and subscription billing via Stripe. The architecture is a monorepo with shared packages for the database layer (typed Convex operations via Effect Schema), a custom React reconciler for Discord messages (Reacord), an AI agent component for streaming chat threads with vector search, and observability integrations (OpenTelemetry, Sentry, PostHog, Axiom). Effect-TS is used pervasively for dependency injection, error handling, and structured concurrency across the bot and web backend. The system is highly modular, testable (dedicated convex-test package and Effect-based test layers), and demonstrates advanced patterns in type-safe database access, real-time streaming, and Discord bot engineering.
Cal.diy is a fully open-source, MIT-licensed fork of Cal.com, providing a self-hostable scheduling platform. It is a large monorepo containing a Next.js web application (apps/web) for booking pages, settings, and admin, a NestJS API (apps/api/v2) for platform REST endpoints, and extensive packages for business logic (packages/features), integrations (packages/app-store with 50+ apps), embeddable booking widgets (packages/embeds), and reusable React atoms (packages/platform/atoms). The architecture uses tRPC for client-server communication, Prisma ORM with PostgreSQL, Redis caching, and a custom dependency injection system (ioctopus) alongside NestJS DI. Key patterns include a tasker abstraction for async/sync background jobs (webhooks, emails, calendar sync), a versioned webhook payload builder factory, repository pattern over Prisma, and a consistent app-store integration structure. The platform exposes a public API with OAuth2, webhooks, and embeddable components for third-party developers. The codebase is actively maintained with frequent schema migrations and CI/CD pipelines, but exhibits some technical drift due to dual API surfaces (tRPC vs REST), stub implementations for enterprise features, and generated files that require regeneration.