NETROOM
Excalidraw is a virtual whiteboard for diagrams in a hand-drawn style: architecture sketches, user flows, wireframes and anything else that is quicker to draw than to describe. It runs in the browser with no sign-up - open a tab and start drawing. There are libraries of ready-made shapes, export to PNG and SVG, collaboration over a link with end-to-end encrypted rooms, and files you can keep locally or in your own storage. Open source, with a self-hosted option for teams.
Squoosh compresses images in the browser: drop a file in, pick a format and a quality, download the result. A slider puts the original and the compressed version side by side, so you can see exactly where artefacts start and stop just before them. It handles a range of formats, each with its own controls - from a single quality dial to the codec's own parameters. Nothing is uploaded: the work happens on your device, and it runs offline once installed as an app. Built by Google Chrome Labs, open source, no sign-up.
The Cyber Swiss Army Knife, built by the UK's GCHQ. You chain operations into a "recipe" and push text or a file through it: base64, XOR, AES, DES, Blowfish, hashes, hexdumps, X.509 and IPv6 parsing, archive extraction, charset conversion. Everything runs in the browser - nothing is sent to a server, and you can download the page and use it offline. Apache 2.0 plus Crown Copyright. Invaluable for picking apart logs, dumps and suspicious payloads.
A Swiss army knife for PDFs in the browser, running on your own server: merge and split, rotate, compress, convert to and from office formats, OCR, sign, redact, and chain operations through a REST API - over fifty tools in all. The point is that files never reach someone else's cloud. One docker run gets you going, and a desktop client and Kubernetes charts exist too. It is open core: the base is open source while some capabilities sit behind paid Server and Enterprise plans.
Remote desktop written in Rust. You connect to another screen with no account and, more to the point, no dependence on someone else's servers - run your own relay and the traffic never touches vendor infrastructure. Clients exist for Windows, Linux, macOS, Android and iOS, with file transfer and audio forwarding. It feels a lot like TeamViewer minus the sudden 'commercial use detected' lockouts. AGPL-3.0. The public relays are congested, so a self-hosted one is close to mandatory; extras ship as the paid Server Pro.
A full backend wrapped around plain Postgres: authentication, auto-generated REST and GraphQL, realtime subscriptions, file storage, Deno edge functions and vector search for AI work. The real difference from Firebase is that underneath sits an actual relational database - you write the schema and the SQL, and row-level security enforces access. Assembled from open pieces like PostgREST, GoTrue and Realtime, Apache 2.0 licensed, self-hostable with Docker Compose and a CLI for local dev. The cloud free tier pauses idle projects.
Per-second infrastructure monitoring that mostly configures itself. Install the agent and it auto-discovers hardware, containers, databases and services across 800+ integrations, then draws the dashboards for you. Anomaly detection runs as ML on the node itself, and metrics stay local by default instead of shipping to someone else's cloud. The agent is GPLv3 and costs roughly 5% of a core and ~150MB RAM. Linux, FreeBSD, macOS and Windows; the UI is free but proprietary, and Netdata Cloud sells SSO and RBAC.
A Node.js headless CMS: define content types through the admin UI or in code and get REST and GraphQL APIs, roles and permissions, a media library, drafts and localisation. Plugins and lifecycle hooks extend it, and the React admin panel can be reshaped to fit the project. Databases are your pick of PostgreSQL, MySQL, MariaDB, or SQLite for local work. The core is MIT while enterprise pieces - SSO, audit logs, fine-grained permissions - sit in paid editions. Host it anywhere, or buy Strapi Cloud with database and CDN included.
Uptime monitoring for your own server: HTTP(S), TCP ports, ping, DNS records, keyword matching on a page, JSON queries, WebSocket, Docker containers and push checks for cron jobs. Over 90 notification channels including Telegram, Discord, Slack, Gotify and email. It also tracks SSL certificate expiry and can publish public status pages. Needs Node.js 20.4+ or just Docker, and stores everything in SQLite, so there is no external database to run. MIT-licensed and genuinely a one-command install.
Meta's React-based documentation site generator. You write Markdown or MDX and get a static site with docs versioning, localisation, dark mode, Algolia DocSearch integration and a blog out of the box. Customisation happens through ordinary React components, so you can swap out any part of the theme by shadowing it. MIT licensed and deployable anywhere, GitHub Pages included. It is a natural fit if your team already lives in React; for a purely content site with no developers around it is overkill.
A self-hosted front end for chatting with models. It talks to a local Ollama and to any OpenAI-compatible API, and keeps working offline. Beyond the chat window there is document RAG, image generation, voice and video calls, a plugin system and role-based access, so a whole team can share one deployment. Needs Python 3.11+ or Docker (CUDA for GPU), with SQLite or Postgres behind it. The licence is custom: source is open, but you must keep the 'Open WebUI' branding unless you qualify for an exemption.
Turns any URL into clean data for language models: it crawls a site without needing a sitemap, renders dynamic pages, and returns markdown, HTML, schema-guided structured JSON, screenshots and links. SDKs and LangChain and LlamaIndex integrations are included. Licensed AGPL-3.0 and self-hostable, though the self-hosted build is noticeably thinner than the cloud one. The free tier gives 1,000 credits a month with only 2 concurrent requests; paid plans start at $16/month.
The project has changed direction sharply: the repo was renamed from lobehub/lobe-chat to lobehub/lobehub, and it has grown from a polished chat shell into a platform for running a team of agents - hiring them, scheduling them, and getting reports on 24/7 operation. The old strengths remain: one-click deploy to Vercel or Docker, dozens of model providers, plugins, speech and vision. The licence is bespoke - the LobeHub Community License, Apache-2.0 plus commercial-use conditions.
A spreadsheet UI bolted onto a real database. Point it at Postgres or MySQL and the tables show up as grids, kanban, gallery, calendar and forms, with role-based access and a REST API on top. Handy when non-technical colleagues need to touch production data and you do not want to build an admin panel for it. Runs via Docker, a macOS/Linux/Windows binary, or a one-line server install; SQLite works for local trials. Mind the licence: Sustainable Use, so internal use is fine but reselling it as a SaaS is not.
A Rust search engine you can have running in five minutes: push in JSON and get instant search with typo tolerance, faceting, synonyms, custom ranking and highlighting. It answers in tens of milliseconds, stays reasonable on memory, and ships SDKs for nearly every language plus prebuilt UI components. Hybrid and vector search are supported. Licensing is split: the main codebase is MIT while Enterprise Edition features fall under Business Source License 1.1. Cloud starts at $20/month; self-hosting is free.
A publishing platform for people who earn from what they write: posts, newsletters, paid subscriptions through Stripe, tiered memberships, built-in SEO and Handlebars themes. Content and Admin APIs mean Ghost works happily as a headless backend behind your own frontend. Node.js and MIT licensed. Self-hosting is free and reasonably simple, though email delivery and payments are still separate services you wire up. Managed Ghost(Pro) is paid, and it funds the non-profit foundation that owns the project.
A whole backend in one box: auth, databases, storage, functions, realtime, messaging and hosting, either as a Docker stack you run yourself or on Appwrite Cloud. SDKs cover web, Flutter, Android, iOS and React Native, which makes it an easy fit for mobile teams. Licensed BSD-3-Clause, so no copyleft strings. The cloud free tier gives 5GB bandwidth, 2GB storage and 75k monthly active users, but caps you at two projects and pauses them after a week idle. Pro starts at $25/month.
The forum engine that has held the bar for over a decade: infinite scroll instead of pagination, user trust levels, real moderation tooling, mailing-list style notifications you can reply to from email, full-text search, and a large catalogue of plugins and themes. Rails and Ember on PostgreSQL, licensed GPL-2.0. Install it with the official Docker script - the stack is hungry, wanting a couple of gigs of RAM and a working SMTP provider. Discourse's own hosting is paid, and it funds the project.
A backend in a single file. Download the Go binary and you get SQLite, a REST-ish API, OAuth authentication, file storage, realtime subscriptions and an admin dashboard. It is exactly the right size for prototypes, side projects and small apps where a cluster would be absurd. Official SDKs for JavaScript and Dart; extend it in Go or through the embedded JS VM. MIT-licensed, running on Linux, macOS, Windows, FreeBSD and NetBSD. One caveat: before 1.0 backwards compatibility is not promised, so upgrades can bite.
A team chat server you run yourself: channels, threads, calls, bots, Matrix federation and an omnichannel widget for customer support. It fits places where conversations legally cannot leave the building - banks, healthcare, government - and supports fully air-gapped deployments. Node.js and MongoDB underneath, installed via Docker, Podman or Kubernetes. The code is open, but the free self-hosted plans cap how many users you get, and advanced roles, auditing and support are paid. Check the current cap before planning a rollout.
Error and performance monitoring: stack traces with source context, breadcrumbs, release tracking, commit attribution, alerting and sane grouping of duplicate crashes. SDKs cover 20+ languages and platforms - JS, Python, Go, Rust, Java, PHP, Dart and Flutter. The licence needs care: FSL-1.1 bars you from building a competing service on this code, but every release converts to Apache 2.0 automatically after two years. Self-hosting is officially supported yet heavy - Postgres, ClickHouse, Kafka and Redis, so budget 16GB RAM minimum.
A video player for macOS that looks and behaves like a native Mac app while running mpv underneath, which means it plays essentially any format without codec hunting. It supports Touch Bar, picture-in-picture, dark mode, thorough subtitle handling with auto-download, playlists, trackpad gestures and JavaScript plugins. Written in Swift, GPL-3.0 licensed, entirely free and still actively developed. Mac only - there is no Windows or Linux build and none is planned.
Open-source BI you point at your database to build dashboards. Non-technical people assemble questions by clicking; analysts drop into raw SQL and build models on top. Ships as a Docker image or a JAR and talks to Postgres, MySQL, BigQuery, Snowflake and dozens more. The OSS edition is AGPL and free; SSO, granular permissions, row-level sandboxing and white-labelling sit in the commercial editions. A managed cloud exists if you would rather not run it yourself.
An issue tracker with cycles, modules and product roadmaps - closer in feel to Linear than to heavyweight Jira, but you can run it on your own box. Views come as list, kanban, calendar and gantt, with estimates, custom properties and wiki-style pages alongside. Django, Postgres and Redis under a React front end, deployed via Docker Compose or Kubernetes. AGPL-3.0, with some capabilities reserved for the commercial editions, and a free cloud tier if you would rather skip the ops entirely.
Your own PaaS on your own hardware: point it at a VPS, give it repo access, and you get push-to-deploy, automatic SSL, managed databases, backups and 280-plus one-click services. Built on Laravel with everything running in Docker. Apache-2.0 licensed, and self-hosting is free with no feature gates - you only pay for the cloud version, where Coolify runs the control instance for you. The server itself, and keeping it patched and secure, is still entirely your job.
One API instead of a pile of vendor SDKs: define a workflow and the notification goes out over email, SMS, push, Slack, Telegram or an in-app inbox. Over 70 providers are wired in - SendGrid, Twilio, FCM, OneSignal and the rest - plus a drop-in React inbox component so you are not rebuilding the bell icon. Useful once the 'who gets notified, where and when' logic has spread across your codebase. Core is MIT, the enterprise folder is commercial. Cloud has a free tier, self-hosting is supported.
Personal finance: accounts, transactions, budgets, investments and assets in one dashboard with genuinely good charts. It is a handsome project, but not one to adopt now: the repo is archived, development stopped at the v0.6.0 final release, and the last commit was July 2025. You can still self-host it with Docker, and AGPL-3.0 permits forking, but Maybe's name and logo are trademarks that forks may not use, and the README requires stating clearly that a fork is unaffiliated.
Kong's API client for REST, GraphQL, gRPC, WebSockets and SSE: collections, environments, request chaining, code generation, mock servers, and the Inso CLI for running tests in CI. Collections can live locally, in a git repo, or in the cloud - local storage came back after the 2023 backlash over forced accounts. Apache-2.0 licensed. The free tier covers git sync for up to 3 users and 1,000 mock requests a month; Pro is $12 per user per month.
Editors' picks