Confluence and Notion both want your team's documentation in their cloud; Docmost, an open-source collaborative wiki platform, keeps it on your server. The centerpiece is a Notion-style block editor with CRDT-based real-time collaboration: multiple people edit the same page simultaneously and changes merge without conflicts or overwrites. Content lives in spaces - per team, project, or department - with nested page trees, role-based permissions, groups, inline comments, page history with restore, and full-text search across everything. The editor covers tables, code blocks, callouts, KaTeX math, and file attachments, and diagramming is built in rather than bolted on: Mermaid, Draw.io, and Excalidraw all render inside pages, alongside embeds for Airtable, Loom, Miro, and more. Migration paths include Notion, Markdown, HTML, and ZIP archive imports (Confluence, PDF, and DOCX importers ship in the Enterprise edition, along with SSO via SAML/OIDC/LDAP and MFA). The stack is TypeScript with PostgreSQL and Redis, deploys via Docker Compose, runs in air-gapped environments with no external dependencies, and is translated into 10+ languages. The AGPL-3.0 community edition carries no per-seat fees; the project has passed 20,000 GitHub stars since its 2024 launch.

Roughly 43% of all websites and over 60% of the CMS market run on WordPress - the GPL-licensed platform that scales from a personal blog to publishing operations and WooCommerce stores. The Gutenberg block editor composes pages from reusable blocks, and full site editing extends block control to headers, footers, and templates; tens of thousands of plugins and themes cover essentially every capability a site might need, from SEO and caching to membership and e-commerce. WordPress 7.0 "Armstrong" marks the platform's biggest structural update since Gutenberg itself: a React-based DataViews admin replaces the legacy list tables with instant filtering, a provider-agnostic AI Client API ships with connectors for OpenAI, Anthropic, and Google, media processing moves into the browser via WebAssembly, and a universal Font Library manages typography across block, hybrid, and classic themes with local hosting for GDPR compliance. New Breadcrumbs, Icons, and lightbox Gallery blocks reduce plugin dependence, and server-side PHP block registration simplifies development. The REST API and WP-CLI make it automatable end to end. Self-hosting is what WordPress was designed for: your content, database, plugin choices, and upgrade schedule stay entirely under your control, free of wordpress.com plan limits.

Between your databases and everything that consumes data - BI tools, embedded analytics, AI agents - sits Cube (formerly Cube.js), an open-source semantic layer. Metrics, dimensions, joins, and access rules are defined once as code in YAML, JavaScript, or Python, forming a governed data model that every downstream consumer shares, so "revenue" means the same thing in every dashboard. Caching is two-level: an in-memory cache absorbs bursts of identical queries, and declared pre-aggregations - rollup tables built in the warehouse or in Cube Store, Cube's distributed columnar engine, and refreshed in the background - deliver sub-second latency while cutting warehouse compute costs. The query planner routes each request to cache, rollup, or source automatically. Consumers connect through a Postgres-compatible SQL API (any tool that speaks Postgres works), plus REST, GraphQL, and a Meta API for model introspection. Row-level security and multi-tenancy are enforced in the layer itself, upstream of every client. Sources include Snowflake, BigQuery, Databricks, Postgres, MySQL, Presto, and Athena. Headless by design - bring your own UI.

Prompt, run, edit, and deploy full-stack Node.js applications from a browser tab: Bolt.diy is the official open-source version of Bolt.new's AI coding agent. Its foundation is StackBlitz's WebContainer technology - a sandboxed in-browser Node.js environment where the AI controls the whole stack: filesystem, npm, dev servers, terminal, and browser console. That means the agent does not just generate code; it installs dependencies, runs Vite or Next.js, reads errors, and fixes them. The defining difference from Bolt.new is model choice per prompt: 19+ providers including OpenAI, Anthropic, Gemini, DeepSeek, Groq, Mistral, Amazon Bedrock, and local models via Ollama or LMStudio, extensible through the Vercel AI SDK. Development ergonomics include live preview, a diff view of AI changes, codebase search, file locking to prevent generation conflicts, 15+ starter templates (React, Vue, Next.js, Astro, Svelte, Expo), and MCP support for external tools. Projects integrate with Git and Supabase, and deploy in one click to Vercel, Netlify, or GitHub Pages.

Links rot - the hard truth Linkwarden is built around, as a collaborative bookmark manager that preserves what it saves. Every page you save is fully preserved - a screenshot, a PDF, a self-contained single-file HTML archive (generated by the Monolith Rust binary), and a clean reader view - so the content survives even after the original site disappears. Think of it as a private Wayback Machine you own, with an optional one-click snapshot to archive.org on top. The reading experience matches the archival rigor: a distraction- free reader view supports text highlighting and annotation, and full-text search across everything you have saved is powered by Meilisearch. Optional AI tagging analyzes page content and auto-assigns tags - generate new ones, pick from your existing set, or constrain to predefined tags - with providers ranging from local Ollama models (fully private) to OpenAI, Anthropic, and OpenRouter. Organization is collections, sub-collections, and multiple tags per link; teams collaborate on shared collections with per-member permissions, and public collections share curated link sets (with preserved copies) to anyone. The stack is Next.js/React on TypeScript with PostgreSQL via Prisma, NextAuth supporting credentials, OAuth2, and SAML SSO, and a Playwright-driven headless Chromium worker doing the capture. Native iOS and Android apps and browser extensions feed it from anywhere.

Most wikis die of flat page-and-tag sprawl; BookStack's defining decision is enforced structure - an MIT-licensed PHP/Laravel platform (over MySQL) where content lives in a hierarchy of shelves, books, chapters, and pages, the way a physical library works. A shelf maps to a department, a book to "Engineering Runbooks," a chapter to "Database Procedures," a page to the actual document. That opinionation removes the "where does this go?" friction and keeps knowledge bases tidy as they grow. Editing works both ways: a clean WYSIWYG editor for most users, a Markdown editor with live preview for those who prefer it - switchable per page. Full-text search spans all books or scopes to one, with direct links to individual paragraphs, and include tags let you embed one page's content inside another so shared blocks update everywhere at once. Every edit creates a diffable, revertible revision. Page templates standardize recurring formats, tags add cross-cutting categorization, and built-in diagrams.net integration draws architecture diagrams in place. Authentication covers email/password plus OIDC, SAML2, LDAP, and social login; a full role and permission system locks content down per shelf, book, or page. Pages and books export to PDF, HTML, plain text, and Markdown, a REST API automates content, and the whole thing runs happily on the cheapest VPS you can find.

In continuous open-source development since 2009, Etherpad is the original really-real-time collaborative editor - used by Wikimedia, governments, EU public-sector institutions, and tens of thousands of self-hosters. Its core idea is visible authorship: every keystroke is attributed with author colors, every revision preserved, and the timeslider lets you scrub through a document's entire history character by character. Multiple people type into the same pad and see each other's changes instantly - it scales to thousands of simultaneous editors per pad. The base install is deliberately lightweight; capability comes from roughly 290 plugins installable from the admin web UI: comments, images, tables, drawing, video chat via WebRTC, math rendering, code highlighting, and authentication via OAuth, LDAP, or OpenID. AI is pointedly a plugin, not a default - you choose the model and infrastructure, or never turn it on. There is no telemetry. For integrators, an HTTP API (with OpenAPI definitions at /api/openapi.json) manages pads, users, and groups for embedding in your own applications, and the ueberDB abstraction layer supports PostgreSQL, MySQL, Redis, MongoDB, and SQLite backends. Full data export is built in, the format is open, it is translated into 105 languages, and it runs on anything from a Raspberry Pi to a server farm. Apache 2.0 licensed, Node.js based.

Contracts signed on your own server: DocuSeal is the most feature-complete open-source, self-hosted alternative to DocuSign. A WYSIWYG builder turns any PDF into a fillable form with 14 field types: signature, initials, date, file upload, checkbox, dropdown, radio, stamp, and more. Documents route to multiple submitters in sequence or parallel, with automated SMTP email notifications, reminders, and a mobile-optimized signing experience that works on any device without an account. Every completed document carries an automatic PDF eSignature with verification and an audit trail. Templates are reusable and can also be generated programmatically - from HTML via API or from PDFs and DOCX files with embedded field tags - and the REST API plus webhooks drive full workflow automation, with embedded signing forms and form builders for React, Vue, Angular, and plain JavaScript. Files store on disk or in S3, Google Cloud Storage, or Azure. The UI ships in 7 languages with signing in 14. Runs on SQLite, PostgreSQL, or MySQL; AGPL-3.0 licensed with unlimited documents and no per-signature fees.

Private npm packages without shipping code to the public registry or paying for npm Enterprise: Verdaccio is the standard lightweight, zero-config private registry and caching proxy. It runs as a single Node.js process with its own tiny embedded database; no external database is required to start. Point npm, yarn, or pnpm at it and everything behaves as expected: install, publish, unpublish, dist-tags, and deprecation all work against the standard npm endpoints. The uplink system is where it earns its keep: packages not found locally are fetched from configured upstreams (npmjs.org, yarn, JFrog, Nexus, or another Verdaccio), cached as tarballs, and served locally thereafter - cutting CI latency and surviving registry outages. Multiple uplinks chain for failover, and per-package glob patterns in config.yaml route scopes to specific upstreams while controlling access, publish, and unpublish rights per group. You can even override a public package by publishing a patched version under the same name locally. A plugin architecture swaps in auth backends (htpasswd default, LDAP and others available), storage drivers (S3, Google Cloud Storage), middleware routes, and metadata filters. With official Docker images and a Kubernetes Helm chart, it slots into any pipeline in minutes.

Machine translation with no Google, no Azure, no per-character billing, and no text leaving your infrastructure: LibreTranslate is a free, open-source translation API that runs entirely on your own server. The engine underneath is Argos Translate, which runs OpenNMT neural models with SentencePiece tokenization and Stanza sentence-boundary detection, all offline. Models install as portable .argosmodel packages covering dozens of languages - English, Spanish, French, German, Chinese, Japanese, Russian, Arabic, Hindi, Portuguese, and many more - and Argos handles automatic pivoting: with es-to-en and en-to-fr installed, it chains them to translate es-to-fr without a direct model. The API is a straightforward HTTP POST to /translate with source and target language codes, returning JSON - simple enough that the ecosystem has clients in every major language and integrations across tools like Weblate and Mastodon. Beyond plain text it translates HTML while preserving markup and handles whole file uploads (documents in, translated documents out), plus automatic language detection when the source is unknown. A clean bundled web UI serves interactive translation for end users, and optional API keys with rate limits control access. AGPL-licensed and trainable with custom models, it is the standard answer when translation must be private, unmetered, and self-contained - GDPR-sensitive text never touches a third party.

Real-time alerts from your own infrastructure to your phone, with no Firebase, Pushover, or third-party push service in the path: Gotify is a simple, self-hosted notification server written in Go. The model is deliberately minimal: senders push messages with a single HTTP POST to the REST API, receivers subscribe over a WebSocket stream, and a clean React web UI manages the pieces. Senders are namespaced as "applications," each with its own token, so your backup script, Uptime Kuma, CI pipeline, and cron jobs each get an identity, an icon, and independently revocable credentials - centralized alerting from many services with per-source management. Messages carry a title, body, and priority level that maps to notification importance on the client. The official Android app (on both F-Droid and Google Play, notable for working entirely without Google Play Services) shows push notifications for new messages; the web UI itself supports Web Push in the browser; and gotify/cli pushes messages from shell scripts with one command. A server-side plugin system adds custom behavior, and the whole thing runs as a single small binary with SQLite by default - near-zero resource footprint. Because dozens of tools (and Apprise) speak Gotify natively, it slots in as the notification hub for an entire homelab or ops stack.

Run a Stack Overflow of your own: Apache Answer brings the question-and-answer format in-house, maintained under the Apache Software Foundation with an Apache-2.0 license. You use it to run a community forum, product help center, or internal knowledge base where content lives as questions and answers rather than wiki pages. It ships the mechanics that make that format work: voting, accepted answers, a reputation system with privilege levels, tagging, full-text search with filters, revision history on every edit, and admin/moderator/user roles. Content is written in Markdown with real-time preview and code syntax highlighting. A plugin system covers OAuth login (Google, GitHub), S3 storage, external search backends like Algolia, and Akismet anti-spam, and a REST API exposes platform data for integration. The backend is Go, the frontend React, and it runs against SQLite, MySQL, or PostgreSQL. Self-hosting replaces per-seat tools like Stack Overflow for Teams with a flat-cost instance where you own all the content.

No database anywhere in the stack: Grav, the leading flat-file CMS, builds every page from a folder of Markdown and YAML on PHP, Symfony components, Twig templating, and Doctrine caching. That architecture is the whole argument: content is Git-versionable, rsync-able, and lock-in-free; pages render in well under 100ms without database round-trips; and backup means copying a directory. Content authors write Markdown (or plain HTML), configure with readable YAML, and define custom page structures via blueprint files that generate editing forms automatically. The optional Admin panel adds a polished editing layer: dashboard with site activity, page management with a syntax-highlighted editor and live preview, drag-and-drop media uploads, one-click plugin/theme updates, and normal/expert modes for form-based or raw YAML editing. The ecosystem runs deep - hundreds of open-source plugins and themes installed through the GPM package manager, with an event-hook architecture that gives plugins full control over the request lifecycle, and downloadable skeletons providing entire pre-built sites. Grav 2.0 modernizes the stack (PHP 8.3+, Symfony 7, Twig 3) and adds a first-party REST API, an MCP server for AI agents, and a SvelteKit single-page admin with real-time collaborative editing. Ideal for docs, blogs, and marketing sites. MIT-licensed.

The fediverse's answer to YouTube comes from French non-profit Framasoft: PeerTube is a TypeScript/Angular video platform where hundreds of independently operated instances federate over ActivityPub into one network. Videos you publish are discoverable across the whole video fediverse, and viewers can follow your channels from Mastodon or any ActivityPub platform - or plain RSS - without needing an account on your instance. The namesake innovation attacks video hosting's core cost problem: alongside HLS delivery, an optional WebRTC-based P2P layer lets concurrent viewers' browsers share video segments with each other, so a video going viral distributes its own bandwidth demand instead of crushing your server; instance redundancy extends this by letting friendly instances cache each other's videos. Livestreaming is first-class - stream via OBS or any RTMP software, host permanent streams, enable replays, and interact through live chat. Creators get channels, playlists, analytics, built-in video editing (trim, watermark), and an embeddable player for any website. There are no ads, no data mining, and no recommendation algorithm engineered for watch-time - the project's explicit design stance. Admins control federation policy, P2P settings, and theming; a plugin system extends the rest. AGPL-licensed, 300+ contributors, in active development since 2015.

Authentication that lives inside your application rather than behind a redirect to an external identity provider - SuperTokens takes a fundamentally different architecture from Auth0 and AWS Cognito. Three tiers make that work - frontend SDKs (React, Angular, Vue, vanilla JS, React Native) render overridable login UI and manage tokens; backend SDKs (Node.js, Python, Go) expose auth endpoints on your own API domain; and SuperTokens Core, the piece you host here, is the stateless HTTP service handling core auth logic, password hashing, token signing, and database operations against PostgreSQL. The recipe system keeps features decoupled: use email/password, social login, passwordless (magic links, OTP), phone-password, multi-factor authentication (TOTP, WebAuthn), user roles, and microservice auth - individually or combined; you can even use SuperTokens purely for session management alongside another login provider. Sessions are where it shines: rotating refresh tokens with theft detection, automatic access-token refresh, CSRF protection, and secure cookie handling out of the box - the details that become vulnerabilities when hand-rolled. Verification happens locally in your backend via cached JWT signing keys, so the Core stays off the hot path. Self-hosted means no user limits, free forever, with all user data in your database. Apache-licensed.

Forum software rebuilt on the modern web stack: NodeBB runs the classic bulletin-board format - categories, threads, local accounts - in real time, on Node.js over MongoDB, Redis, or PostgreSQL. WebSockets stream new posts into open topics as they're written and deliver instant notifications for follows, likes, and subscriptions; built-in chat supports side-by-side private conversations. The headline of recent versions is core ActivityPub federation: your forum can follow, share, and converse with other NodeBB instances, Mastodon, Lemmy, and anything else that speaks the protocol, turning an isolated community into a fediverse node. Everything beyond the common core is a plugin - more than 500 plugins and themes install in one click from the admin panel, covering SSO providers, search backends like Elasticsearch and Solr, galleries, calendars, and more. The theming engine extends base templates with SCSS/CSS on Bootstrap 5, plus a drag-and-drop widget system and custom HTML/CSS/JS injection. Operators get a real-time analytics dashboard, human-readable SEO-friendly URLs with semantic markup, multilingual UI, and full read and write REST APIs for integration. Mobile-first rendering means the same install works everywhere. For communities that outgrew phpBB but don't want Discourse's weight, NodeBB is the natural middle.

Add a series once, set a quality profile, and everything downstream is automated: Sonarr is the smart PVR for Usenet and BitTorrent users. It monitors RSS feeds from your indexers, detects new episodes the moment they release, sends matching grabs to SABnzbd, NZBGet, qBittorrent, Deluge, or another download client, then renames files with fully configurable templates, sorts them into consistent folder structures, and notifies Plex, Kodi, or Jellyfin to update the library. Quality profiles define what's acceptable (HDTV, WEB-DL, Blu-ray, up to 4K) and an upgrade cutoff - when a better release appears, Sonarr replaces the existing file automatically, stepping from HDTV to WEB-DL to Blu-ray until the cutoff is met. Custom formats add weighted scoring for finer-grained release selection, with community-maintained TRaSH Guides presets as the widely accepted defaults. Failed downloads are handled without intervention: Sonarr retries with another release, and manual search shows every candidate with the reasons any was rejected. It scans existing libraries for missing episodes, fully supports specials, multi-episode files, and daily and anime series types, and a calendar view shows upcoming episodes across every tracked show. Runs on Linux, Windows, macOS, and Raspberry Pi, and pairs naturally with Prowlarr for centralized indexer management.

Encrypted, incremental, compressed backups on storage you already have - Amazon S3, Backblaze B2, Google Drive, Azure, OneDrive, Dropbox, MEGA, Storj, WebDAV, SFTP, FTP, SMB, or a plain local disk - is what the MIT-licensed Duplicati has quietly done for years. Its security model is Trust No One: every block is encrypted with AES-256 (or a local GPG instance) before leaving the machine, and the passphrase never travels, so the storage provider holds only ciphertext. The block-based storage engine gives the best of both backup worlds: after one initial full backup, only changed data blocks upload - modify a tiny part of a huge file and only that part transfers - yet every backup version restores like a full backup in a single operation, with no incremental chains to replay. Deduplication and compression keep remote storage growth slow even across years of versions. A web interface manages everything: the built-in scheduler keeps backups current automatically, flexible filters select folders, file types, or custom patterns, retention policies prune old versions, and an integrated updater flags new releases. On compatible object-lock backends, immutable (WORM) storage protects backup data from ransomware that reaches the credentials. Runs on Windows, macOS, and Linux, free even for commercial use.