Budibase is an open-source low-code platform for building AI agents, internal applications, and automations. It provides a visual builder (Svelte frontend) for designing screens, data models, and workflows, backed by a Koa.js server and worker services. The platform supports multi-tenancy, self-hosting via Docker/Kubernetes, and a cloud offering. Core capabilities include a drag-and-drop app builder, an automation engine with triggers and steps, AI agent creation with LLM integration and knowledge bases, external datasource connectivity (REST, SQL, NoSQL, S3, etc.), role-based access control, SCIM provisioning, and audit logging. The architecture follows a monorepo pattern with distinct packages for server, worker, builder, client, pro features, CLI, and shared libraries, using CouchDB as the primary document store, Redis for caching/queues, and S3/MinIO for object storage.
Polar is an open-source, full-stack monetization platform designed for AI-era software developers. It serves as a Merchant of Record, handling checkout flows, subscriptions, usage-based billing, seats, discounts, and global tax compliance. The system is built as a monorepo with a Python/FastAPI backend (async SQLAlchemy, Dramatiq workers, PostgreSQL, Redis, Tinybird for event analytics), a Next.js web dashboard and customer portal, a React Native mobile app (Expo), a design system (Orbit), and multiple SDKs (TypeScript, Python) with a CLI tool. Architecture follows a service-oriented pattern with versioned REST APIs (2026-04, 2026-10, 2027-01), a repository pattern for persistence, benefit fulfillment strategies for integrations (Discord, GitHub, Slack, license keys), and framework adapters (Next.js, Nuxt, TanStack Start, Better Auth) for easy integration. The platform also includes an internal backoffice (HTMX/tagflow), observability (SLOs, invariants, Prometheus metrics), and merchant migration tooling from Stripe.
OpenStatus is a production-grade, self-hostable uptime monitoring, incident management, and status page platform. In production, it runs multi-region synthetic checks (HTTP, TCP, DNS, ICMP, gRPC) from Go-based checker and private-location services, streams check results into Tinybird for time-series analytics, persists workspace state (monitors, pages, incidents, API keys, OAuth clients) in SQLite via Drizzle ORM, and renders results through a Next.js dashboard and a public, i18n-enabled status page app with custom-domain proxy support, password/email/IP access gating, themes, and RSS/JSON/markdown feeds. A Hono-based API server exposes three API surfaces - a frozen legacy REST v1 (OpenAPI), tRPC, and ConnectRPC - plus an MCP server for AI agents and a Slack bot that can resolve incidents conversationally. The architecture is a deliberately polyglot monorepo: 8+ apps (dashboard, status-page, web marketing, Hono server, Go checker, Go private-location, Deno workflows, Go ssh-server) and 20+ internal packages. Business logic is centralized in packages/services behind a consistent ServiceContext + withTransaction + requireScope + emitAudit mutation pattern, then adapted to tRPC, ConnectRPC, and REST entry points. Multi-tenant workspaces include plan-based limits, API keys with scopes, a full OAuth 2.0 authorization server (PKCE), WorkOS SSO, Stripe billing, and append-only audit logging. Background Deno workflows handle cron maintenance: outbox draining, status drift repair, OAuth client pruning, and uptime freezing. Craftsmanship is strong: the service-layer pattern is applied uniformly, there is an explicit ServiceError hierarchy mapped to both tRPC and gRPC errors, external services (Upstash, Tinybird, Slack, analytics) have thorough test doubles, and several packages are genuinely standalone and reusable (CDN header analysis, assertion engine, schema-driven data-table filters, Effect-based status fetchers). Caveats are real but not disqualifying: the REST v1 API is explicitly frozen and bypasses the service layer, identical composition/chart utilities are duplicated across dashboard and status-page apps, a deprecated screenshot-service remains in-tree, the Go/TypeScript protobuf boundary requires manual synchronization, and an in-progress auth migration has left Clerk-era references alongside NextAuth. Overall this is a well-architected, actively maintained codebase that does what it claims.
Kvaesitso is a production-grade, search-focused Android launcher and home-screen replacement. The app aggregates local and cloud content - apps, contacts, calendar events, files, locations, websites, Wikipedia articles, calculator results, and unit conversions - through a unified `SearchService`, then presents results in a Jetpack Compose UI with configurable widgets, themes, gestures, and plugin-backed data sources. It ships a ContentProvider-based plugin SDK that lets third-party packages extend search, weather, calendar, contact, file, and location providers. Cloud integration includes Nextcloud/ownCloud file search, multiple weather providers (Met.no, BrightSky, OpenWeatherMap), OpenStreetMap/Overpass location lookup, and a Material You-style color engine for theming. Architecturally this is a large modular monorepo with 40+ Gradle modules layered into `app`, `core`, `data`, `services`, `libs`, and `plugins`. Dependencies are wired with Koin; persistence uses Room with 30+ schema versions and hand-written migrations plus DataStore; concurrency is Kotlin coroutines and Flow; the UI is Compose/Material3. Primary entry points are `LauncherActivity`, `AssistantActivity`, the settings activities, and the plugin SDK. The codebase demonstrates strong separation of concerns, repository-per-domain organization, and a substantial library of custom Compose components for settings, bottom sheets, drag-and-drop, widgets, and animations. Despite active maintenance and nightly CI, drift signals exist: reflection into hidden `StatusBarManager` for global actions, many deprecated compatibility fields and migrations, hardcoded web/feed blocklists, and several external API integrations that can change without notice. The strongest, most reusable pieces are isolated algorithms and parsers: fzf-style fuzzy matching, OSM opening-hours parsing, searchable string normalization, and map tile rendering. These are genuinely extractable and would transfer cleanly to other search or geodata projects.
Bouncy Castle for .NET is a comprehensive, production-grade cryptographic library providing implementations of a vast range of symmetric and asymmetric ciphers, hash functions, message authentication codes, digital signatures, key agreement protocols, key encapsulation mechanisms (including post-quantum schemes like ML-KEM, ML-DSA, SLH-DSA), secure random number generation (NIST SP 800-90A DRBG), and ASN.1 encoding/decoding (DER, BER, DL). It supports high-level protocol implementations for TLS/DTLS (client and server, including PSK, SRP, and post-quantum key exchange), OpenPGP (RFC 4880/9580), CMS (Cryptographic Message Syntax), CMP, CRMF, OCSP, TSP, and X.509 certificate generation and validation. The library is designed as a class library with a monolithic architecture organized into namespaces (Org.BouncyCastle.Crypto, .Asn1, .Tls, .Bcpg, .Cms, etc.), exposing both low-level primitives and high-level builders. It targets multiple .NET runtimes with conditional compilation for hardware intrinsics (AES-NI, PCLMULQDQ, SSE/AVX) and Span<T> support. The codebase is actively maintained, with ongoing migration from older algorithm names (e.g., Dilithium → ML-DSA) and extensive use of factory patterns and interface-based abstractions, making it a solid foundation for secure application development.
RustyRAG is a production-grade RAG (Retrieval-Augmented Generation) API server written in Rust, designed for sub-200ms time-to-first-token. It provides a complete pipeline: document ingestion (PDF, DOCX, PPTX, XLSX, HTML, TXT, ZIP) via Docling with layout-aware extraction, OCR, table recognition, and optional vision-model image descriptions; hybrid search using Milvus (dense HNSW vectors + BM25 sparse with Reciprocal Rank Fusion); cross-encoder reranking via Jina Reranker v3; and streaming LLM responses from Groq or Cerebras. The server exposes REST endpoints for document upload, semantic search, RAG chat (both full response and SSE streaming), collection backup, and an evaluation benchmark runner. The architecture follows a clean layered pattern: Actix-web handlers in `src/handlers/` orchestrate business logic, services in `src/services/` encapsulate external API clients (Milvus, embeddings, reranker, Docling, LLM), and schemas in `src/schemas/` define request/response types with OpenAPI annotations via utoipa. The Rust binary is a single self-contained server; GPU-accelerated sidecars (embeddings, reranker, Docling) run as Docker containers. Configuration is environment-driven with sensible defaults. Key entry points are the HTTP API at `/api/v1/` (Swagger UI at `/swagger-ui/`) and a built-in chat UI at `/static/chat.html`. The primary data flow for a RAG query is: embed user query → fire concurrent dense and BM25 searches in Milvus → merge via RRF → rerank top candidates → build context prompt → stream LLM response with source citations and timing metadata. The system is designed for low latency and high accuracy, with benchmark results showing 94.5% pass rate with reranker at ~279ms TTFT.
RustDesk is a full-featured, open-source remote desktop application written primarily in Rust with a Flutter frontend. In production, it enables remote control, file transfer, clipboard synchronization, audio/video streaming, TCP tunneling, printer sharing, and camera streaming across Windows, macOS, Linux, Android, and iOS. The architecture is a client-server model with a rendezvous/relay server for NAT traversal, a plugin system for extensibility, and platform-specific backends for screen capture (DXGI, X11, Wayland, Quartz, Android MediaProjection), input simulation (enigo), and clipboard file transfer (RDP-based protocol with FUSE on Unix). Key entry points include `src/main.rs` (CLI), `src/server.rs` (host service), `src/client.rs` (remote session), and the Flutter UI in `flutter/`. Data flows involve encrypted peer-to-peer connections (NaCl), adaptive video codec selection (VP8/VP9/AV1/H264/H265 with hardware acceleration), and IPC via named pipes with OS-level authentication. External dependencies include libvpx, libyuv, FFmpeg, Opus, and platform-specific SDKs (Windows IddCx, macOS CoreGraphics, Linux Wayland/D-Bus). The codebase is actively maintained with frequent commits, CI/CD pipelines, and a large community (120k+ stars).
AppFlowy is an open-source AI workspace application (Notion alternative) with a Rust backend and Flutter frontend. The system provides document editing, database views (grid/board/calendar), AI chat and completion, cloud sync, collaboration, file storage, and search. It employs a modular, event-driven architecture using a custom plugin system (lib-dispatch) and protobuf code generation. The backend is split into many small crates with clear trait abstractions for cloud services, storage, and field types. Notable strengths include a well-structured database type-option system, a priority task scheduler, and support for local AI via Ollama. Weaknesses include a complex dependency graph, custom build tools, and some duplicate test infrastructure. Overall, it is a high-quality, actively developed product with strong engineering practices.
OpenMontage is an open-source, agentic video production platform where an AI coding assistant (Claude Code, Cursor) orchestrates the entire pipeline. It provides a library of 100+ tools (video generation, audio, graphics, enhancement, analysis, avatar, subtitles) behind a scored provider selection layer, and 10+ production pipeline manifests (animated explainer, cinematic, documentary montage, talking head, etc.) that define stage order, approval gates, and tool assignments. The core architecture is a Python framework with a BaseTool class, ToolRegistry for auto-discovery, pipeline loader, checkpoint system, and a Remotion-based video composer. It also includes a Backlot living storyboard server for live production monitoring and an Ink Theater procedural puppetry engine. While primarily an application, it contains data/research elements such as ManimGL/ManimCE educational animation examples covering transformer internals, quantum mechanics, and ML concepts, as well as a CLIP-based corpus builder for documentary montage pipelines.
Twenty is a production-grade, open-source CRM delivered as a large Nx monorepo. The system is a full-stack TypeScript application: a NestJS backend (twenty-server) exposing GraphQL/REST APIs, a React frontend (twenty-front) with Jotai-based state management, a shared UI component library (twenty-ui), and shared TypeScript packages (twenty-shared). It provides multi-tenant workspaces, object-record CRUD with custom data models, role-based permissions, AI chat/agent capabilities (model tiers, tool calls, streaming), analytics via ClickHouse, and a CLI scaffolding tool (create-twenty-app) for bootstrapping custom apps. The architecture is modular with NestJS ConfigurableModuleBuilder patterns, event-driven design using Zod-validated schemas, and component-scoped state via atom families and component instance contexts.
JSON Crack is an open-source, browser-based tool for visualizing, formatting, converting, and exploring JSON, YAML, CSV, and XML data as interactive graphs. The monorepo (Turborepo) contains four workspaces: a Next.js web app (apps/www) that provides the full editor experience with a Monaco-based text editor, split-view layout, graph canvas, and various utility modals (jq, JSONPath, schema validation, code generation); a VS Code extension (apps/vscode) that embeds the same graph view as a webview panel; a Chrome extension (apps/chrome-extension) that injects a 'Raw'/'Graph' toggle on any JSON page; and a reusable React component package (packages/jsoncrack-react) that exposes `JSONCrack` as a standalone component along with a `parseGraph` utility and TypeScript types. All data processing happens client-side — the app is a fully static Next.js export served behind NGINX. The architecture is frontend-only, relying on Zustand for state, reaflow for graph layout, react-zoomable-ui for pannable/zoomable canvas, and jsonc-parser for AST-driven parsing. The codebase is well-organized, with clear separation of concerns, good TypeScript coverage, and unit tests in the core package.
drawDB is a free, open-source, client-side web application for designing relational database schemas and generating SQL. It provides an interactive ER diagram editor with support for multiple database dialects (MySQL, PostgreSQL, SQLite, MariaDB, MSSQL, Oracle), import/export in SQL, DBML, JSON, Mermaid, and Markdown, and features like auto-arrange, auto-connect foreign keys, schema validation, migration generation, and versioning via GitHub Gists. The architecture is a React single-page application (Vite + Tailwind CSS + Semi UI) with state managed through custom React Contexts and hooks, persistence via IndexedDB (Dexie), and an optional cloud backend through an extension system. It is primarily an application, with no data research or ML components.
Postiz is a full-stack, open-source social media scheduling and publishing platform that supports 30+ platforms (Instagram, TikTok, LinkedIn, YouTube, X, Facebook, etc.). The system is built as a pnpm monorepo with four main applications: a Next.js frontend (App Router), a NestJS backend REST API, a Temporal-based workflow orchestrator for reliable post publishing and token refresh, and a Chrome extension for cookie-based authentication. It also includes a CLI app, a public SDK (@postiz/node), and a shared libraries layer for business logic, database access (Prisma + PostgreSQL), and integrations. Key architectural patterns include an abstract social provider base class (SocialAbstract) that all platform integrations extend, a Temporal v1.8+ workflow engine with versioned posting workflows (v1.0.1 through v1.0.8), an upload factory abstracting local and Cloudflare storage, an MCP server for AI agent tools (scheduling, content generation via LangGraph), a plug/auto-reply system, and a short-link abstraction with multiple providers. The frontend uses Zustand for state management, SWR for data fetching, CopilotKit for AI textarea integration, and Mantine/Tailwind for UI. The system handles OAuth flows, subscription billing via Stripe, team collaboration, webhooks, and admin monitoring. The codebase demonstrates strong engineering with reusable abstractions for social integrations, storage, email, and short-linking, though it carries some technical debt from organic growth (multiple workflow versions, hardcoded strings, and suppressed TypeScript strictness).
VoltAgent is a large TypeScript monorepo for building, deploying, observing, and evaluating AI agents. The core package provides an agent runtime with tool calling, memory, subagents, guardrails, workflow orchestration, MCP client integration, A2A protocol support, voice, and OpenTelemetry-based observability. Framework adapters expose this runtime as HTTP/SSE/WebSocket servers via Hono, Elysia, and serverless function providers, while a CLI scaffolds projects and manages VoltOps deployment/auth flows. The repo is fundamentally an application framework, though it contains hybrid data-oriented subsystems: a RAG package with many document chunking strategies, vector adapters, and BM25 search, plus evaluation/scoring packages used for LLM benchmark experiments.
Pixelorama is a full-featured open-source pixel art editor built with the Godot Engine (GDScript). It provides a professional-grade environment for creating pixel art, sprites, tiles, and animations. The application includes a rich set of drawing tools (pencil, line, curve, shape tools, bucket, gradient, shading), selection tools (rectangle, ellipse, lasso, magic wand, color select), and a comprehensive layer system supporting pixel, group, tilemap, 3D, and audio layers. Animation is handled through a timeline with keyframe interpolation, onion skinning, and frame tags. The editor supports a variety of import and export formats including Aseprite, Krita, Photoshop, Piskel, PNG, GIF, APNG, MP4 (via FFmpeg), and its own .pxo project format. It features a dockable UI, customizable shortcuts, extension support, shader-based non-destructive layer effects, and a built-in noise generator and gradient editor. The codebase demonstrates a well-structured tool inheritance hierarchy, a robust undo/redo system, and several reusable custom UI widgets and addons.
This repository is a curated directory of self-hosted, open-source alternatives to popular SaaS products (VPN, photo hosting, cloud storage, email, chat, notes, password managers, kanban, etc.). The primary deliverable, README.md, is not hand-maintained: it is generated by readme-gen.py from a structured JSON dataset (dyos-db.json) containing roughly 180 projects grouped into ~37 service categories. Each project record stores name, description, GitHub URL, site URL, star count, last-push timestamp, and an ETag cache key. The repo answers: 'What self-hosted services exist for any given SaaS category, and how actively maintained is each option?' A GitHub Actions cron (maintenance.yml) runs daily. keep-alive.py iterates every GitHub-hosted project, queries the GitHub REST API for current star counts and pushed_at dates, and uses If-None-Match/ETag conditional requests so unchanged repos return cheap HTTP 304 responses - a genuinely thoughtful pattern that avoids rate-limit exhaustion across ~150 repos. Results are written back to dyos-db.json, then readme-gen.py regenerates the README with relative recency labels (🟢 under a month, 🟠 under a year, 🔴 older) and per-category star sorting. Both scripts use only the Python standard library, so the dependency surface is zero. Hybrid note: although it contains application-style CLI automation scripts, the dominant character is data curation - the JSON dataset and its rendered markdown output are the product, not the scripts. Data lineage is GitHub API plus manual community submissions (via the issue template) into dyos-db.json, transformed into README.md. Reproducibility is high: cloning and running readme-gen.py regenerates the README offline with no dependencies; keep-alive.py needs only a GitHub token loaded from environment or .env. The codebase is small, has no tests, and its value lies in the curated data and the clean maintainability tooling rather than in complex engineering.
HeyForm is an open-source form builder and management platform designed for small businesses. It provides a full-stack solution with a React-based drag-and-drop form builder, a NestJS GraphQL API backend, a standalone form renderer for public-facing forms, and an embed script for third-party sites. The system supports a wide range of field types (text, choice, rating, payment, signature, etc.), conditional logic with branching, multi-language internationalization, Stripe payments, AI-assisted form generation via OpenAI, and integrations with popular services like Slack, Notion, and Google Sheets. The architecture follows a monorepo pattern with shared packages for answer validation, utility functions, and type definitions, enabling code reuse across the server, webapp, and renderer. The backend is built with NestJS, MongoDB (Mongoose), Redis (Bull queues), and Apollo GraphQL, with scheduled jobs for cleanup and async task processing. The frontend uses React 19, Tailwind CSS, Zustand for state management, and Apollo Client for GraphQL communication. Security is a strong focus: the codebase includes SSRF protection, upload content validation, rate limiting, atomic verification codes, and extensive input sanitization. The project has a comprehensive test suite covering unit, integration, and end-to-end scenarios, including a permission matrix with over 270 cases. Despite some duplicated logic and large locale files, the overall code quality is high, with well-structured modules and clear separation of concerns.
This repository contains raygui, an immediate-mode GUI library for the raylib game programming library. It is written entirely in C as a single header file (src/raygui.h). The library provides over 25 controls (buttons, sliders, text boxes, list views, color pickers, etc.) designed specifically for building development tools, debug overlays, and editors. The architecture follows an immediate-mode pattern where controls are drawn and return their state every frame, with no retained state managed by the library, making it highly predictable and easy to integrate into existing game loops. A powerful styling system allows complete customization of colors, fonts, and metrics, with over 20 pre-built themes provided in the styles/ directory. The library also includes a built-in icon system with 256+ 16x16 icons. While tightly coupled to raylib by default, a standalone mode (RAYGUI_STANDALONE) allows it to be adapted to any graphics library by implementing a small set of backend functions. The examples directory contains several high-quality, reusable custom widgets (curve editor, property list, file dialog) that demonstrate how to extend the library. The codebase is mature, well-documented, and actively maintained, representing a high standard of C library craftsmanship within its domain.
Inspira UI is a curated collection of beautifully designed, copy-paste-ready Vue/Nuxt UI components, inspired by Aceternity UI and Magic UI. The repository serves both as a component library and a documentation/demo site built with Nuxt 4, Tailwind CSS v4, and a rich ecosystem of animation and WebGL libraries (motion-v, Three.js, OGL, GSAP). The architecture is a standard Nuxt application with i18n (English, French, Chinese), content management via @nuxt/content, and a custom registry system that generates component metadata for CLI installation. Key entry points include the Nuxt configuration (nuxt.config.ts), the app configuration (app.config.ts) for UI theming, and the registry build script (scripts/build-registry.mts) that crawls component files and produces Zod-validated schemas. The primary data flow is static: markdown documentation files in content/ are rendered alongside live interactive playgrounds that allow users to tweak component props via DialKit config panels. External dependencies are heavy but modern, including motion-v for spring animations, Three.js/OGL for WebGL effects, canvas-confetti for particle effects, and @vueuse/core for utilities. The codebase demonstrates consistent patterns (barrel exports, cn() class merging, shader-based backgrounds, context injection for compound components) and a strong emphasis on visual polish and developer experience.
Lobsters is a production-grade Ruby on Rails application powering the social news aggregation and discussion site lobste.rs. It provides a full-featured platform for submitting, voting, commenting, and moderating links, with a focus on computing and technology topics. The architecture follows standard Rails MVC patterns with a rich set of controllers, models, views, mailers, and background jobs, using SQLite in production with SolidQueue for job processing and SolidCache for caching. The codebase emphasizes self-hosting, minimal external dependencies, and optional JavaScript, with a strong moderation system featuring hats, flags, bans, and a detailed moderation log. Key features include story submission with duplicate detection, threaded comments with Reddit-style confidence sorting, tagging and filtering, user invitations, private messaging, mod mail, full-text search, RSS feeds, and Fediverse integration via Mastodon. Authentication supports bcrypt, TOTP two-factor, and OAuth (GitHub, Mastodon). The application includes extensive test coverage with RSpec, factory_bot, and VCR for external HTTP interactions, and employs custom monitoring and security measures such as IP spoofing protection, rate limiting (Rack::Attack), and SSRF protection in its HTTP client. While primarily a standard Rails application, it contains several well-crafted, reusable components such as a custom HTTP client with SSRF protection, a Markdown renderer with username linking, and reusable concerns for token generation and username validation. The codebase is actively maintained with regular commits, though it acknowledges some 'dusty corners' and technical debt, such as inline partial duplication and a few brittle deployment-specific configurations. Overall, it is a solid, well-structured application that demonstrates good Rails engineering practices.