Scheduling infrastructure, not just a booking page - Cal.com is the leading open-source scheduling platform. Share a link, attendees pick a slot, and real-time sync against Google Calendar, Outlook, and CalDAV prevents double-booking. Beyond the basics it covers team workflows: round-robin distribution, collective availability across multiple hosts, recurring meetings, and routing forms that ask bookers questions and send them to the right team member - the feature sales and support teams usually pay enterprise prices for. Paid bookings run through Stripe, video calls through the built-in Cal Video (Daily.co) or Zoom and Google Meet, and an app store connects 100+ tools including HubSpot, Zapier, and n8n. The API-first architecture with webhooks and embeds makes it practical to build scheduling into your own product, white-labeled with your domain and branding. Built on Next.js and Prisma over PostgreSQL, translated into 65+ languages, with the self-hostable community codebase maintained under an open-source license.

Originated as Alibaba Group's official internal AI code review assistant serving tens of thousands of developers and identifying millions of code defects over two years before open-sourcing in May 2026 — now at 21,000+ GitHub stars — Open Code Review is the production-hardened platform that proves enterprise-grade code review can be fully open-source under Apache 2.0. The hybrid architecture separates deterministic engineering pipelines (file selection, diff parsing, rule matching for NPE, thread-safety, XSS, and SQL injection across 10+ languages) from LLM-powered agent reasoning with tool-use capabilities including FileRead, CodeSearch, and cross-file context inspection, consuming approximately one-ninth the tokens of general-purpose coding agents while delivering line-level precise comments with severity and confidence scoring. The bundled web dashboard (port 4173) provides review management, findings triage, result browsing, and direct GitHub posting without external dependencies, while the session viewer (port 5483) renders full LLM request/response traces for debugging and auditing. Integration spans GitHub Actions, GitLab CI, GitFlic CI, and Gerrit with delegation mode enabling Claude Code, Cursor, and other AI agents to leverage OCR's engineering logic alongside their own LLM reasoning. Supports OpenAI, Anthropic, Google Gemini, DeepSeek via built-in providers plus Ollama and vLLM for air-gapped deployments. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. Apache 2.0 licensed.

3X-UI is the most popular open-source Xray management panel, providing a full-featured web interface for deploying and monitoring proxy and VPN protocols on Linux servers. The Go backend manages Xray-core instances supporting VLESS, VMess, Trojan, Shadowsocks, WireGuard, Hysteria2, HTTP, SOCKS, Dokodemo-door, and TUN inbounds across TCP, mKCP, WebSocket, gRPC, HTTPUpgrade, and XHTTP transports secured with TLS, XTLS Vision, and REALITY. The Clients page tracks each user with individual traffic quotas, expiration dates, concurrent connection limits, and live online status indicators, while one-click share links, QR codes, and a built-in subscription server distribute configurations in multiple output formats. The multi-node architecture manages and scales deployments across multiple servers from a single panel instance. The Panel Settings page configures listen address, port, URI path, session duration, trusted proxy CIDRs, authentication, and Telegram bot integration for remote monitoring and management alerts. Outbound routing supports WARP, NordVPN, custom rules, load balancers, and proxy chaining. Xray Configs provides template-level control over the core configuration, while the API Docs page exposes a complete RESTful API with in-panel Swagger documentation. Data persists in SQLite by default or PostgreSQL for larger deployments, with database export and import from the panel. Fail2ban integration enforces per-client IP limits. On RepoCloud, deploy 3X-UI on a dedicated VPS with Docker, root SSH access, and complete control over your proxy infrastructure, all under the GPL-3.0 license.

GitNexus turns any codebase into an interactive knowledge graph that maps every dependency, call chain, functional cluster, and execution flow, giving AI coding assistants the deep structural awareness they need to stop breaking things. Drop a repository URL or ZIP file into the browser-based explorer and watch Tree-sitter parsers decompose your code into a navigable property graph you can zoom, click, and query. The MCP server integrates directly with Cursor, Claude Code, Codex, Antigravity, and other editors through 16 specialized tools covering architectural queries, impact analysis, safe multi-file renames, change detection, and cross-repo contract matching. Need to know the blast radius before touching a shared utility? The impact analyzer traces every caller, implementer, and downstream consumer in milliseconds. Teams reviewing pull requests get automated blast-radius annotations powered by the same graph. The registry architecture lets a single MCP server manage multiple indexed repositories simultaneously, so switching between projects requires zero re-indexing. For visual exploration, the web interface renders interactive community-clustered graphs where you can trace execution paths, browse file trees, and chat with an AI agent grounded in the graph's structural data rather than raw file snippets. Everything runs locally; your source code never leaves the machine. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. PolyForm Noncommercial 1.0.0 licensed.

Created by Jeff Atwood, co-founder of Stack Overflow, and battle-tested for over a decade with 47,600+ GitHub stars, Discourse powers community forums for GitHub, Docker, Rust, Netlify, and thousands of organizations worldwide. The platform combines long-form threaded discussion with built-in real-time chat, enabling communities to move fluidly between asynchronous conversations and live interaction. Five automated trust levels progressively unlock permissions — posting links, editing wiki posts, flagging content, and moderating — based on reading time, post count, and community engagement, reducing spam and abuse without manual intervention. The Discourse AI plugin integrates with OpenAI, Anthropic, and self-hosted HuggingFace endpoints for automated topic summarization, sentiment analysis, semantic search, and AI-assisted content triage. Over 200 official and community plugins extend functionality with features like the Data Explorer for ad-hoc SQL queries against the forum database, polls, solved-topic marking, voting, calendar events, and custom user fields. SSO and OAuth support connects Google, Facebook, Apple, GitHub, and SAML identity providers, while reply-by-email and mailing list mode let users participate entirely through their inbox. The Ember.js single-page frontend delivers responsive performance across all devices with PWA support and web push notifications. Deployment uses Docker via the official discourse_docker launcher with automatic Let's Encrypt HTTPS, resource scaling based on server hardware, and support for single-container or multi-container configurations. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. GPL v2.0 licensed.

Your prompts never have to leave the building: TextGen runs open large language models on your own hardware behind a chat interface and an API that speak fluent OpenAI. Load GGUF or Hugging Face weights through llama.cpp, ik_llama.cpp, Transformers, ExLlamaV3, or TensorRT-LLM, and switch models or backends from the interface without restarting the server. Chat mode gives you conversations with characters and system prompts, notebook mode behaves like a familiar completion editor, and both accept image attachments for vision models and documents for context. Models that support tool calling can search the web, fetch pages, and do math through single-file Python tools, and MCP servers plug in for larger tool catalogs. Start it with the API flag and the same model answers at chat, completions, and messages endpoints that mirror OpenAI and Anthropic, complete with streaming, logprobs, embeddings, and optional API key authentication. Portable builds for Linux, Windows, and macOS bundle every dependency, so the distance from download to a running model is an unzip and one shell command. Because everything is local, prompts, documents, and outputs stay on machines you control, and parallel request handling lets a single loaded model serve a whole team's tools at once. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. AGPL-3.0 licensed.

A pile of paper becomes a searchable digital archive under Paperless-ngx, the community-maintained document management system. The pipeline is what makes it work: drop a file into the consumption folder (or let it poll an email inbox), and a worker hashes it for duplicate detection, routes it by type, runs OCRmyPDF with Tesseract (100+ languages) on anything without a text layer, and produces an archivable PDF/A with invisible selectable text embedded - so Ctrl+F works on your scans. Then the smart part: a scikit-learn classifier (TF-IDF plus multi-label prediction) trained on your own tagged documents automatically assigns tags, correspondents, and document types to new arrivals, alongside rule-based exact, keyword, and regex matching for deterministic cases. Full-text search includes relevance ranking, match highlighting, autocomplete, and "more like this" similarity search. Apache Tika integration extends consumption to Word, Excel, PowerPoint, and LibreOffice formats. The Django/Angular app adds custom fields, saved views on a customizable dashboard, bulk editing, workflow automation triggered on upload or matching, shareable public links with expiration, and a robust permissions system with per-document access control. Metadata lives in PostgreSQL with Redis-queued Celery workers processing documents in parallel. Your tax records, invoices, and contracts stay on your server - searchable in seconds, never in someone else's cloud.

With over 46,000 GitHub stars and one of the largest communities in data engineering, Apache Airflow is the workflow orchestration platform that lets teams define, schedule, and monitor complex data pipelines as Python code through directed acyclic graphs. Airflow 3.x introduced a modernized architecture with a task execution API, the Language Task SDK for writing task implementations in Java and Go alongside Python, asset-based partitioning with FanOutMapper and FixedKeyMapper for data-driven scheduling, a first-class state store for tasks and assets, pluggable retry policies, and a redesigned React-based web UI built on FastAPI. The provider ecosystem ships 80+ packages covering AWS, Google Cloud, Azure, Snowflake, Databricks, Apache Spark, Apache Kafka, PostgreSQL, MySQL, MongoDB, Slack, HTTP, SSH, Docker, Kubernetes, and dozens more, enabling a single deployment to orchestrate jobs across multi-cloud and on-premises infrastructure. The scheduler supports cron expressions, timetable plugins, data-aware scheduling triggered by asset events, and dynamic task generation through Python loops and conditionals. Built-in operators include BashOperator, PythonOperator, DockerOperator, KubernetesPodOperator, and sensor operators that poll external systems. The web UI provides DAG visualization with Gantt charts, grid views, and graph views, task instance logs, SLA monitoring, connection and variable management, and role-based access control. Deployment options include standalone mode, Docker Compose with CeleryExecutor or KubernetesExecutor, Helm charts for Kubernetes, and managed cloud services. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. Apache License 2.0 licensed.

FreeLLMAPI collapses the chaos of 29 free LLM providers — Google AI, Cerebras, Groq, Mistral, OpenRouter, GitHub Models, Cohere, Cloudflare Workers AI, NVIDIA NIM, HuggingFace, SiliconFlow, Reka, Z.ai, and more — into a single /v1 endpoint that speaks both OpenAI and Anthropic protocols. The smart router selects the best available model for each request, automatically fails over to the next provider when rate limits hit, and tracks per-key token consumption so you never exceed a free-tier cap. Keys are stored with AES-256-GCM encryption and clients authenticate using a single unified bearer token, never exposing upstream provider credentials to downstream applications. The catalog tracks 251 model families across 358 provider/model endpoints with approximately 4 billion tokens per month of aggregate free-tier capacity, auto-refreshing from a signed manifest at freellmapi.co twice daily without requiring git pulls. Beyond chat completions, the proxy handles embedding, image generation, and audio/TTS endpoints, plus structured outputs with JSON schema forwarding, JSON healing, and format-ignore failover. An integrated MCP server at /mcp provides gateway introspection for coding agents, while the self-hosted OpenAPI reference at /v1/docs documents every route. Compatible with OpenAI SDKs, LangChain, LlamaIndex, Continue, Claude Code, and Hermes — just change base_url. Deploy via Docker, npm, or build from source. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.

Backed by over 45,000 GitHub stars and described as the tool that replaces Notion, Evernote, and Anki in a single Docker container, SiYuan is the privacy-first knowledge management system where every paragraph, heading, and list item is a uniquely addressable content block. The block-level architecture enables bidirectional links, transclusion embeds, and SQL query blocks that dynamically aggregate content across your entire workspace, while the knowledge graph visualization maps relationship networks between documents and blocks. Built-in databases support table views with relation and rollup columns, filter composition, sorting, and template-based calculations for structured data management alongside freeform notes. The FSRS spaced repetition engine turns any content block into a flashcard with scientifically calibrated review scheduling, eliminating the need for separate memorization tools. AI integration connects to OpenAI-compatible APIs for writing assistance, translation, summarization, and Q&A chat, with semantic search using embeddings and reranking for intelligent content retrieval. The Bazaar community marketplace delivers plugins, themes, templates, and widgets through a managed extension system with TypeScript plugin APIs. End-to-end encrypted synchronization works across S3-compatible storage, WebDAV servers, or SiYuan's own cloud service, while Tesseract OCR extracts searchable text from images and the web clipper captures pages from Chrome, Edge, and Firefox. Export targets include Markdown with assets, PDF, Word, and HTML. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. AGPL-3.0 licensed.

Every major model provider behind one ChatGPT-style interface: LibreChat spans OpenAI, Anthropic, Google, Azure, AWS Bedrock, Vertex AI, Groq, Mistral, OpenRouter, DeepSeek, and any OpenAI-compatible endpoint including local Ollama. You can switch models mid-conversation and compare providers without changing tools. Its Agents framework builds no-code custom assistants with tool access via Model Context Protocol servers, file search over uploaded documents through an optional pgvector-backed RAG service, and a sandboxed Code Interpreter that executes Python, JavaScript, Go, C++, Java, PHP, and Rust. Artifacts render React components, HTML, and Mermaid diagrams directly in chat, and image generation works through DALL-E and other configured providers. Multi-user support is enterprise-grade, with OAuth, SAML, LDAP, and two-factor authentication, per-user conversation history in MongoDB, and Meilisearch-powered search across all messages and files, plus reusable presets, forkable threads, and persistent memory across conversations. The economics favor teams: instead of a ChatGPT Plus seat per person, everyone shares one instance billed per API token, with access to every provider rather than one - and providers see individual API calls, not your accumulated organizational knowledge. Deployment is Docker Compose; API keys and endpoints are configured through .env and librechat.yaml.

A man-in-the-middle proxy you run on purpose, mitmproxy lets developers and testers inspect, edit, and replay HTTP and HTTPS traffic from any client. Point a browser, phone, or script at it and every HTTP/1, HTTP/2, HTTP/3, WebSocket, and TLS-protected connection appears as a flow you can open, search, and filter. Content views turn payloads from HTML to Protobuf into readable text. Intercept a request or response before it moves on, change its headers, body, or status by hand, then release it, or save the flow and replay it to the client or the server later. Map local and map remote rules answer requests with files or other URLs, while blocklists, anticache, sticky cookies, and proxy authentication cover routine test chores. Choose the interface that fits the job: a keyboard-driven terminal console, mitmweb in the browser with a Capture tab that sets up WireGuard devices with a QR code, or mitmdump for unattended logging in scripts. Proxy modes include regular, local capture, WireGuard, transparent, reverse, upstream, SOCKS5, and DNS. Addons written in Python add custom rewriting, recording, and automation. Teams use it for debugging, testing, privacy measurements, and penetration testing. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.

With over 45,000 GitHub stars and 100 million Docker pulls, Milvus is the most widely adopted open-source vector database, powering production AI systems at NVIDIA, Salesforce, eBay, Airbnb, and DoorDash. The distributed architecture separates compute and storage with stateless microservices on Kubernetes, horizontally scaling query nodes for read-heavy workloads and data nodes for write-heavy ingestion independently. Milvus 3.0 introduces lake-native retrieval that builds and serves indexes directly over vector data in object storage and open formats including Parquet, Lance, Iceberg, and Vortex without maintaining separate copies. Native hybrid search unifies lexical BM25 full-text retrieval and semantic vector search in a single engine with metadata filtering, eliminating the need for separate search infrastructure. Hardware-accelerated ANN indexing supports IVF, HNSW, DiskANN, and GPU-based indexes with BitQ 1-bit quantization cutting memory usage by 72 percent. SDKs for Python, Go, Node.js, and Java provide programmatic access, while Milvus Lite offers lightweight embedding for local development via pip install. Server-side aggregation, sorting, faceted search, StructArray for nested document structures, and ColBERT multi-vector scoring move ranking and result processing into the engine. The Path Index enables 100x faster JSON filtering with support for 100,000+ collections per cluster for multi-tenant deployments. Self-hosting deploys via Docker Standalone or Kubernetes with Helm charts using S3-compatible, GCS, or Azure Blob storage backends. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. Apache 2.0 licensed.

Blast off into productivity space with Rocket.Chat SIX, the ultimate team collaboration cosmos! Imagine a place where your messages, tasks, and projects all live in harmony, orbiting around your team's efficiency like a well-organized galaxy. This isn't just any old chat platform; it's a customizable universe where you're the master of your data domain, with the power to tweak, integrate, and innovate to your heart's content. Ready to provide stellar customer service? Engage with your clients in a way that's so contextually on-point, they'll feel like you're mind-reading across the cosmos. Plus, with a chat engine that's like a gravitational pull for user engagement, your app or website will become the center of your users' universe. And for the security-conscious space cadets, fear not! Rocket.Chat SIX is locked down tighter than a spaceship hatch, with end-to-end encryption and a buffet of deployment options to satisfy your security appetite. All this, hosted on RepoCloud, where the cost is as lightweight as zero-gravity. So why settle for a terrestrial tool when you can have a celestial experience? Rocket.Chat SIX: because your team deserves to collaborate in a universe that's light-years ahead!

T3 Code puts every coding agent you already pay for behind one control surface, so Claude Code, Codex, Cursor, Grok Build, OpenCode, and Antigravity all run on your server while you direct them from your phone, browser, or desktop. Start a thread, choose the provider and model that fit the job, and watch the agent work in a shared conversation instead of a terminal you have to babysit. Permission modes decide when an agent must stop and ask, and its approvals, questions, and plan reviews arrive in the same thread wherever you happen to be connected from. When the work lands, review it file by file in the built-in diff view, then commit, push, and open pull requests through the Git and GitHub integrations without leaving the app. A real terminal sits beside the chat, and projects, settings, and scheduled tasks stay attached to the machine where the code actually runs. Install it as a background service and reach it from anywhere through T3 Connect, a Tailscale or LAN pairing, or the hosted web client, with a pairing code guarding local access. Outside agents can also drive threads over MCP, launching, messaging, and waiting on work across machines you have linked together. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.

Hyperswitch from Juspay delivers the most comprehensive open-source payment orchestration stack available — a Rust-built platform that connects to Stripe, Adyen, Braintree, Worldpay, Checkout.com, Cybersource, and 120+ payment processors through a single API integration. Intelligent routing drives each transaction to the processor with the highest predicted authorization rate using rule-based, volume-based, and machine learning algorithms, while seamless failover and automatic retries recover revenue from declined transactions using 30+ parameters including decline codes, card BIN, transaction size, and region. The PCI-compliant card vault stores payment methods securely in a dedicated service separate from the main application server, and the reconciliation engine automates 2-way and 3-way matching with backdated support, staggered scheduling, and customizable audit-ready outputs. The Control Center dashboard provides visual workflow builders for routing rules, payment analytics, and operations management. Cost observability tools drill into scheme, interchange, and acquirer fees to detect anomalies and optimize processing costs. The modular architecture allows deploying individual components — routing, retries, vaulting, observability, or the full suite — without vendor lock-in. The web client SDK collects payment information with prebuilt UI components and supports WooCommerce integration. Deploy via Docker Compose with the app server, control center, card vault, and PostgreSQL. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. Apache-2.0 licensed.

Backed by 44,000 GitHub stars and trusted by over four million developers, Sentry is the debugging platform that captures errors, traces, replays, profiles, and metrics from your applications and connects them all through distributed tracing. The error tracking engine captures full stack traces with source context, breadcrumbs, and automatic demangling for native crashes, while intelligent grouping consolidates duplicate events into actionable issues with regression detection and automatic assignment. Performance monitoring instruments your frameworks automatically, capturing every database query, API call, cache hit, and queue operation as spans within distributed traces that flow across frontend, backend, and mobile boundaries. Session Replay produces video-like recordings of real user sessions showing DOM interactions, network requests, console messages, and errors on a synchronized timeline, with AI-powered summaries that describe what happened without watching the full replay. Continuous profiling captures CPU execution data at the function and line level for Node.js, Python, iOS, and Android, linking slow spans directly to the exact code responsible. Cron monitoring tracks scheduled jobs for failures, missed runs, and duration anomalies. The alerting engine fires notifications through Slack, PagerDuty, Opsgenie, and webhooks on new issues, regressions, error spikes, or when latency and crash-free session rate thresholds are crossed. Self-hosted deployment runs as a Docker Compose stack with PostgreSQL, ClickHouse, Kafka, Redis, and Relay. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. FSL licensed.

Backed by 44,000 GitHub stars and now part of Figma, Payload is the first headless CMS that installs natively into your Next.js application's /app directory rather than running as a separate service. The code-first architecture uses TypeScript config files to define collections, globals, and field schemas — from which Payload auto-generates database tables with migrations, a fully customizable React admin panel, REST and GraphQL endpoints, and type-safe Node.js local APIs you can call directly in React Server Components. The Lexical-based rich text editor supports block-based layout building, inline media embeds, and nested field structures, while the built-in localization engine handles unlimited locales with field-level translations. Authentication ships out of the box with HTTP-only cookie sessions, CSRF protection, role-based access control definable at the document, field, and operation level, and support for OAuth providers. Version history tracks every document change with full draft and publish workflows, and Live Preview renders content edits in real-time using server components. The job queue system manages background tasks and multi-step workflows deployable via Vercel Cron or standalone workers. Database flexibility spans PostgreSQL, MongoDB, and SQLite through swappable adapters, and the plugin ecosystem includes official modules for SEO, form builders, redirects, nested documents, and search alongside hundreds of community extensions. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.