From a PDF plan set to a waste-adjusted material order takes one browser tab: OpenTakeoff measures floors, walls, and fixtures at the drawn scale and never uploads a single drawing. Drag in a PDF, image, or zip plan set, view up to four sheets side by side, and search sheet text, while stitching joins floors split across a match line. Scale comes from the drawn scale note or a known dimension, and a check tool reports percent error before a wrong scale can skew a bid. Area, linear, and count tools carry condition colors, CAD hatches, waste percentages, and wall heights, and a marquee over the architect's finish schedule turns approved rows into conditions. Supporting materials convert coverage rates into rounded-up order quantities, and roll-goods mode lays out lanes, seams, and cuts to scale. Totals in SF, SY, LF, and EA export to CSV, JSON, Excel, print, or a marked-set PDF, while named revisions compare addenda as quantity deltas. Highlighters, revision clouds, callouts, and notes mark up sheets on a layer that is never counted, and dimension lines label measured lengths at the sheet scale. An MCP server with more than 50 tools lets AI agents open plans, set scale, and measure rooms, and each shape they draw stays a dashed proposal until a person accepts it. 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.

Estimators, planners, and site teams work from one project record in OpenConstructionERP, a self-hosted construction workspace that carries a job from priced bill of quantities through tender, schedule, and site diary. The BOQ editor organizes sections, positions, and reusable assemblies with overhead, profit, VAT, and contingency markups, validates against DIN 276, NRM, and MasterFormat, and exports to PDF, Excel, CSV, or GAEB XML. Pricing draws on 120,000+ cost items across nine cost bases and a 7,000+ resource catalog, with regional price adjustment and semantic search. Quantities come from PDF plans measured on screen or from RVT, IFC, DWG, and DGN models; a 3D viewer filters elements and links them to BOQ positions, clash detection checks federated models, and an AI estimator drafts positions from text, photos, or drawings via the LLM you connect. Gantt schedules show dependencies and critical path, while earned value and S-curves track budget against actual. Tender comparison lines up subcontractor bids, and contracts, variations, and interim payment claims stay tied to the contract sum. On site, daily diaries with health and safety tracking, punch lists, and a carbon module totaling embodied emissions from the BOQ keep field work in the same system. The interface speaks 44 languages with right-to-left support, 293 guided cases teach real workflows on a demo project, and a REST API, webhooks, and module builder extend it. 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.

draw.io is a free, browser-based diagramming editor for flowcharts, network maps, UML models, and org charts, with nothing to install. An infinite canvas takes shapes from extensive libraries, connectors reroute automatically as shapes move, and ready-made templates replace the blank page. Tables, swimlanes, layers, and tags keep large diagrams tidy, and shape metadata and placeholders attach tooltips, links, and translations. Auto-layout straightens flowcharts and trees. Math typesetting, a simple whiteboard layout, and adaptive dark mode are built in, and custom shape libraries carry your own in-house icon sets. Export to PNG, JPEG, WebP, SVG, HTML, or PDF, embed the diagram data inside PNG and SVG files so they stay editable, or save the full diagram as a .drawio file. Your server stores no diagrams: files go to the user's device, the browser, or Google Drive, OneDrive, and GitLab once you register your own OAuth app. Optional AI diagram generation uses your own provider key, and environment variables set the interface language, fonts, and security policy. 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.

Half the architecture sketches on the internet trace back to Excalidraw - the MIT-licensed virtual whiteboard whose hand-drawn aesthetic made technical diagramming feel approachable, at roughly 85,000 GitHub stars. The infinite canvas offers rectangles, ellipses, diamonds, arrows with smart binding and labels, free-draw, text, images, and an eraser, with full undo/redo, zoom, dark mode, and keyboard-first ergonomics. Community shape libraries add thousands of pre-built elements - AWS architecture icons, flowchart stencils, UI wireframe kits - and everything exports to PNG, SVG, the clipboard, or the open .excalidraw JSON format that keeps drawings diffable and portable. Live collaboration works on a share-a-link model with live cursors and a laser pointer for presenting, and it is end-to-end encrypted by design: the room key travels in the URL hash, which never reaches the server, so the WebSocket relay only ever sees ciphertext. The architecture is remarkably light - the app is a static bundle served by Nginx, drawings persist locally in the browser, and the stateless excalidraw-room relay handles multiplayer - so a self-hosted deployment gives unlimited boards and collaborators with near-zero resource cost, replacing per-editor whiteboard subscriptions.

A Node.js server, a large shared canvas, and a URL - WBO (Whiteboard Ophir) is collaborative whiteboarding reduced to its essence. There are no accounts and no setup - to collaborate, you send someone the board's link, and every stroke appears for all connected users in real time over WebSockets, with cursor positions shared so you can see where collaborators are working. Board state persists automatically and continuously, so a diagram drawn in today's lesson is still there next week at the same URL. Boards come in three flavors: a public free-for-all, private boards with random unguessable names, and named boards with custom URLs shared by anyone who knows the name. The tools cover teaching and brainstorming needs - pencil, straight lines, rectangles, ellipses, text annotations, eraser, a full color palette with brush sizes - and boards export as SVG or PNG. Despite the simplicity, the server is production-minded: JWT authentication gates board access with granular capabilities (open, edit, and clear as separate permissions), rate limiting caps per-client message volume, reverse-proxy and subpath deployment are supported, and OpenTelemetry provides metrics, logs, and traces. It works on tablets and touch devices, speaks multiple languages, and consumes minimal resources. AGPL-licensed.

The drawing surface inside WebRTC conference tools like Meetzi and the LAMS online-learning platform is Whiteboard (by cracker0dks) - a lightweight Node.js collaborative sketchboard built to be embedded and customized, which also slots into Nextcloud via the External Sites app. Everyone opening the same whiteboardid URL parameter draws on the same board, with remote user cursors visible live, per-user undo/redo, and an indicator showing the smallest participating screen so nobody draws outside a colleague's view. Content handling goes beyond pen strokes: drag-and-drop or paste images and PDFs from any PC or browser, then resize, rotate, and draw over them on canvas or background; add text and sticky notes; hold Shift for angle-snapped lines and perfect squares. Every function has a keybinding - deliberately friendly to pen displays like Wacom and XP-Pen whose hardware buttons map to shortcuts. Boards save to image or JSON (with reload), export directly to Nextcloud via WebDAV, and persist across restarts with the file-database option. A REST API with bundled interactive docs allows full programmatic control, an optional access token locks down uploads, and YAML configuration tunes behavior and performance. MIT-licensed and reverse-proxy friendly.

Draw it, write it as code, or hand it to your AI agent: OpenFlowKit is an open-source diagram canvas where the picture and the text behind it are always the same diagram. Drag shapes on the canvas or type a few forgiving lines, and each side regenerates the other as a single undo step. Ten diagram types share that one language: architecture with C4 views and cloud icons, sequence, flowchart, entity-relationship, state, class, mind maps, git graphs, charts, and wireframes. Paste Mermaid, Structurizr, or D2 and it converts into editable shapes, and Copy as Mermaid sends a flowchart or sequence back out for your README. Paste a GitHub repository instead and Map mode draws its architecture for you, with every arrow citing the exact file and line behind it, and a CLI that maps a local checkout for private repos. Connect Claude Code, Cursor, or any MCP client and the agent draws on your live canvas, restyles what is there, and screenshots its own work to check it. A built-in assistant works with your own key from Claude, OpenAI, Gemini, Groq, Mistral, OpenRouter, or a local Ollama, and exports cover PNG, SVG, PDF, JSON, and animated SVG, GIF, MP4, or WebM you can drop into documentation. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.

God's Eye View turns your browser into a real-time spatial intelligence command center, rendering thousands of live aircraft, ships, satellites, earthquakes, traffic flows, and public cameras on a photorealistic 3D Earth powered by CesiumJS and Google Photorealistic 3D Tiles. Click any aircraft to see its transponder telemetry from OpenSky and adsb.lol, including route history, altitude, speed, and callsign; track live vessel positions worldwide through AIS beacon data from AISStream; or follow roughly 840 satellites color-coded by class using orbital elements from CelesTrak. A hands-free voice agent powered by the OpenAI Realtime API lets you ask the planet questions in natural language, and the globe annotates your answer directly in 3D space. Toggle FLIR mode for a thermal camera aesthetic, layer in NASA FIRMS wildfire data, switch between Google 3D, Bing aerial, and OpenStreetMap base layers, or tune into a geolocated world radio dial. Public CCTV cameras are projected into 3D city geometry with viewshed cones and direct-manipulation calibration. The cockpit mode provides a pilot-style briefing surface with mission-specific overlays. Entity inspection panels show detailed metadata for every tracked object, and shareable links let you send any scene configuration to a colleague. Ten of the thirteen live data layers work with zero API keys, while the required Google Maps key offers 1,000 free 3D tile sessions per month. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.