# cnvs.app — Free, No-Signup Collaborative Whiteboard > **TL;DR.** cnvs.app is a free, no-signup, real-time collaborative whiteboard > in the browser. Open a URL, share it, draw and write together instantly. No > accounts, no teams, no paywall. Ships a public Model Context Protocol (MCP) > endpoint so AI assistants can collaborate on the same live board as humans. This Markdown file is a plain-text mirror of , served so AI fetchers (Claude WebFetch, ChatGPT browse, Perplexity, etc.) can read the page without parsing HTML. The HTML version has the same content plus styling, interactive comparison tables, and an FAQ accordion. - Canonical HTML: - Machine-readable docs: · · ## What cnvs.app is cnvs.app is built for the simplest possible use case: two or more people on a call who want to sketch, write or brainstorm on the same surface. You open the site, a board is created, you copy the URL, you share it. Anyone who opens the URL joins the same canvas live. There is no signup, no login, no team setup, no board limit, no session token — just a URL and an infinite sheet of paper. The project is positioned as a minimalist alternative to Miro, FigJam, MURAL, Excalidraw and tldraw. Miro / FigJam / MURAL require accounts and paid plans for team use. Excalidraw's free tier is limited to a single scene. tldraw.com requires every participant to sign in before they can join a shared room. cnvs.app requires none of that. ## What's inside (all on the free tier) - Real-time WebSocket sync across all participants on a board. - Infinite canvas with pan (scroll) and zoom (Ctrl/Cmd/Shift+scroll, pinch). - High-definition vector drawing rendered as SVG paths. - Draggable, editable text nodes with Markdown. - Sticky-note style on any text block (right-click or hover + Y). - **Mermaid diagrams** — flowcharts, sequence, class, state, ER, Gantt, user journeys, mindmaps, timelines, git graphs, C4 — all from plain text. - Clipboard paste for images (PNG/JPEG/WebP/GIF/SVG) and URLs (rendered as clickable capsules). - Radial collision eraser + undo (Ctrl+Z) with live rebroadcast. - One-click print / PDF export with share-URL watermark. - "Hold to delete" wipes the board from the database and reserves the ID for 30 days so stale links show an "erased" overlay. - Light, dark and system themes. - Touch and mobile: two-finger pan, tap to drop text, long-press for marquee select with a Duplicate / Delete action pill. - Installable PWA with offline read-only access to cached boards. - Native MCP (Model Context Protocol) endpoint at `https://cnvs.app/mcp` so AI assistants can read and edit any board alongside humans. ## How cnvs.app compares | Capability | cnvs.app | Miro | FigJam | MURAL | Excalidraw | tldraw | |----------------------------------|-----------|------------------|------------------|----------|--------------------|------------------| | No signup required | Yes | No | No | No | Yes | For sharing only | | Share by URL instantly | Yes | After setup | After setup | After | Yes | Yes | | Real-time multi-user sync | Yes | Yes | Yes | Yes | Plus / self-host | Yes | | Unlimited free collaboration | Yes | No public share | 3 files | Read | 1 scene | Demo only | | Mermaid (flowcharts, sequence …) | Built in | Plugin | Plugin | No | Import only | Via AI | | Price for core collaboration | $0 forever| $8+/user/mo | $3+/user/mo | $10+/u/mo| $0 hosted (1 scene)| $0 hosted (demo) | **Pick cnvs.app** when you want to open a URL, draw on a shared canvas with whoever is on the call, and move on — no signup for anyone, no board limit, no paywall when the team grows. **Pick Miro / FigJam / MURAL** when you need templates, voting, facilitation timers, Jira/Confluence integrations, SSO. **Pick Excalidraw / tldraw** when you want a beautiful, minimal whiteboard and are willing to either sign in (tldraw rooms) or limit yourself to one scene at a time (Excalidraw free tier). ## Collaborate with AI via MCP cnvs.app speaks the [Model Context Protocol](https://modelcontextprotocol.io) so AI assistants like Claude Desktop, Claude Code and any MCP-compatible client can read and edit the same board that you and your teammates are looking at — in real time. Strokes and text nodes the AI adds appear instantly for everyone connected, tagged with an `ai:` author label. ### Endpoint ``` https://cnvs.app/mcp ``` JSON-RPC 2.0 over HTTPS POST. No API key, no OAuth — the **board ID is the key**. Anyone who knows the board ID (the bit after the `#` in the URL) can read and write to that board, just like any human visitor. Keep your board URLs private if the content is sensitive. Optionally a board can be PIN-locked (6 chars a-z0-9): mode `write` requires the key for mutations only; mode `all` requires it for everything. ### Add to Claude Desktop Settings → Developer → Edit Config: ```json { "mcpServers": { "cnvs": { "type": "http", "url": "https://cnvs.app/mcp" } } } ``` ### Add to Claude Code ``` claude mcp add --transport http cnvs https://cnvs.app/mcp ``` ### Tools exposed | Tool | What it does | |-------------------|-----------------------------------------------------------------------------| | `open_board` | Resolve a cnvs URL or ID; creates the board if missing; auto-subscribes. | | `get_board` | Full structured JSON snapshot — IDs, coordinates, text — for precise edits. | | `get_preview` | Schematic SVG render so the model can see layout without blowing up ctx. | | `add_text` | Create / update a text node. Supports Markdown + Mermaid + sticky-note. | | `add_link` | Drop a clickable URL capsule. | | `add_image` | Place a raster / SVG image (data URL, ≤ ~900 kB). | | `draw_stroke` | Freehand stroke from `[x, y]` world-coordinate points. | | `move` | Reposition an existing item by id. | | `erase` | Delete an item by id + kind. | | `wait_for_update` | Long-poll for the next edit. Default 25 s, max 55 s. | Every MCP tool has a 1:1 REST mirror at `POST /api/boards//...` (and `/move`, `DELETE`). REST is universal — any HTTP client can use it without an MCP SDK. ## Privacy & security - **No AI training on your content.** We do not use the contents of your boards to train AI models, ours or anyone else's. - **No activity logging.** No analytics on what you draw, no content logging, no tracking cookies, no fingerprinting. - **Delete is permanent.** Hold-to-delete or 30-day inactivity expiry irreversibly destroys content with no backup. - **Unlisted by design.** Boards are reachable only by URL. No public gallery, no search index, no "explore" feed. - **TLS end-to-end.** Hosted on Cloudflare's edge network. - **Not open source.** We run the service ourselves so the privacy guarantees can actually be enforced. ## Retention Boards are kept for up to **30 days of inactivity**. "Inactivity" means nobody has *read* the board (browser load, `GET /json/`, MCP `get_board`) in 30 days. Writes, SVG/PNG thumbnails, unfurl bots and long-poll waits do NOT reset the clock — only a real read does. After 30 days the contents are purged and the ID is released. If you hold-to-delete a board yourself, the ID is reserved for 30 days so stale links show an "erased" overlay instead of silently creating a new board. ## FAQ (deep links) Each answer has a stable anchor under : - [`#faq-free`](https://cnvs.app/about#faq-free) — Is cnvs.app really free? - [`#faq-account`](https://cnvs.app/about#faq-account) — Do I need an account? - [`#faq-retention`](https://cnvs.app/about#faq-retention) — How long are boards kept? - [`#faq-vs-miro`](https://cnvs.app/about#faq-vs-miro) — vs Miro / FigJam / MURAL? - [`#faq-vs-excalidraw`](https://cnvs.app/about#faq-vs-excalidraw) — vs Excalidraw / tldraw? - [`#faq-privacy`](https://cnvs.app/about#faq-privacy) — Is my data private? - [`#faq-delete`](https://cnvs.app/about#faq-delete) — What happens after I delete a board? - [`#faq-mobile`](https://cnvs.app/about#faq-mobile) — Does it work on mobile / tablet? - [`#faq-offline`](https://cnvs.app/about#faq-offline) — Does it work offline? - [`#faq-mcp`](https://cnvs.app/about#faq-mcp) — Can I connect Claude / an AI to a board? - [`#faq-storage`](https://cnvs.app/about#faq-storage) — Where is the data stored? ## Made by CODER AI cnvs.app is built and operated by CODER AI (), maker of several free productivity tools: - [plugand.ai](https://plugand.ai) — whole-team Slack AI bot, no per-seat. - [plai.chat](https://plai.chat) — private AI chat, 300+ models. - [maxcv.ai](https://maxcv.ai) — AI CV tailored to each job, ATS-optimised. - [whenmeet.me](https://whenmeet.me) — cross-company group scheduling + video. - [mcpfinder.dev](https://mcpfinder.dev) — open-source MCP discovery for agents. Last updated: 2026-05-25.