Open-source AI canvas · Public Craft commons

Start a stroke.
Craft something bigger.

Every big idea starts with one stroke. Think visually with AI, publish the useful step, and let another Crafter take it further—without losing who moved the idea forward.

Download PenEcho Explore public Crafts

PenEcho is an official member of Kimi Open Source Friends.

Launch offer

Every new verified account receives 1,000 welcome credits in its Cloud balance. No card required.

PenEcho being used as a large handwritten AI canvas — Real canvas workflowHandwriting · diagrams · AI in context

A stroke→An idea→A Craft→A living lineage→Something bigger

PenEcho in motion

See what the canvas
actually does.

A complete canvas session at 10× speed: integrals, plots, a maze, and a Feynman diagram — handwriting and AI answers staying side by side the whole way.

Features

Handwriting, diagrams, and AI.
One shared workspace.

PenEcho keeps equations, circles, arrows, sketches, and spatial position together. AI responds beside the exact work you selected, and every result remains a draft you control.

Write, don't translate

Start with marks, formulas, or a rough diagram. No need to flatten every thought into a prompt first.

Answers stay in context

Hints, plots, and explanations appear beside your work — not in a chat window across the screen.

AI drafts you control

Every AI result is a draft: move it, resize it, accept it, or discard it before it becomes your ink.

Room for ideas to grow

A sparse 20,000 × 20,000 canvas, local snapshots, and one-click high-resolution PNG export.

Cloud library, everywhere

Projects live in your private cloud library with thumbnails, recents, and favorites — continue them from any signed-in PenEcho app.

Ideas keep their lineage

Publish a useful step, take another Craft further, and keep every contributor visibly connected to what the idea became.

The public Craft loop

Not a repost. A next step.

Publish opens a Widget or Canvas for attribution-preserving reuse. “Take it further” imports it into your PenEcho host. When you publish your change, the original and your contribution remain connected in a visible lineage.

01PublishMake a useful visual step part of the commons.
02Take it furtherContinue locally with your own tools and model.
03Watch it growSee every version and every Crafter in order.

Explore public Crafts

Model support

Bring a frontier model
you already trust.

Use PenEcho with supported models through your own API key or local CLI. Availability and reasoning controls follow your provider configuration.

Kimi K3Moonshot AI
GPT-5.6 SolOpenAI
GPT-5.6 TerraOpenAI
Claude Opus 4.8Anthropic
Fable 5Claude family
Gemini 3 ProGoogle

How PenEcho connects

Your Canvas can stay local.
Link it live—or save it for anywhere.

PenEcho gives you two cross-device choices. Link Device keeps one Mac, Windows PC, or command-line host live and lets private /canvas/{id} links reach that host. Save to Cloud Project creates a private, versioned project that you can open in another signed-in PenEcho app—even when the original host is offline. On iOS and Android, you can also work independently with an API configured in the app.

Can run as a host

macOS · Windows · command line

One running computer can serve the Canvas, local files, settings, and your configured model or API.

Mac appWindows apppenecho CLI

Download PenEcho npm install -g penecho

Can run independently

iOS · Android

Configure an API inside the mobile app and create directly on that device. This path does not need—or connect to—a computer host.

Your API configuration stays with the app.
The mobile Canvas runs on the device in front of you.
Cloud sign-in still provides community, Favorites, and explicit Project saves.

Private cross-device projects

Save once. Continue in any signed-in app.

Choose Save to Cloud Project from PenEcho to store a private, versioned project under your account. Open it later in another supported PenEcho app and continue from there.

View Cloud Projects The website manages previews, versions, recovery, and downloads. It does not run the Canvas.

Save in a PenEcho appExplicit project save

Private Cloud ProjectVersioned · account protected

Open in another appSame project · another device

Access architecture

Three ways a Canvas runs

Link Device extends a computer host; it does not replace local access. The first two paths reach the same host and local data, while the mobile path runs on that device. Cloud Projects are the private storage and handoff layer between signed-in apps—not a Canvas running on the website.

01 · LocalNo Cloud in the path

Local browserHost computer or local network

PenEcho hostmacOS · Windows · CLI

Open the host's local address. On first start, choose a 6-digit local access code or explicitly continue without one.

02 · Remote after Link DeviceSame host · same local Canvas

Browser or app anywhere/canvas/{id} · signed in

PenEcho Cloud BridgeAccount · CSRF · allow-list · relay

Linked PenEcho hostLocal files · settings · model

Cloud authenticates and transports approved Canvas operations. The linked computer executes them; its API key and private files stay on that host.

03 · Mobile standaloneNo computer host required

iOS or Android appRuns on the mobile device

Your configured APIProvider selected in the app

On-device CanvasIndependent mobile workspace

The mobile app talks to the API you configured and works independently. It does not route through the linked computer.

Set up a host

Local first. Linked when you need it.

The Cloud connection is optional until you want remote access.

1Start PenEchoUse the Mac app, Windows app, or penecho command.
2Configure locallyChoose local access protection and add your model or API.
3Link DeviceSign in and pair this one host to your Cloud account.
4Open it anywhereUse the local address nearby or open a private Cloud Canvas link remotely.

Open Cloud Projects Prepare a host

Choose what crosses devices: Link Device reaches one running host in real time; Save to Cloud Project makes a private project available in your other signed-in apps. Neither local nor bridged access uploads a Canvas automatically.

20,000²logical canvas

SpatialAI keeps visual context

Localyour model, your computer

100%open-source canvas

Open source · AGPL-3.0

Built in the open.
Starred by people like you.

The PenEcho canvas is fully open source — inspect it, self-host it, or shape it. The cloud service is a thin account layer on top, so what you rely on today can never be taken away tomorrow.

AGPL-3.0open canvas license

npmone-line install

Self-hostalways first-class

Star us on GitHub Join the Discord

GitHub stars, growinglive chart · penecho/penecho

github.com/penecho/penecho npmjs.com/package/penecho

Get started

Your first 1,000 credits
are on us.

Create and verify an account to receive 1,000 welcome credits in your Cloud balance. Install PenEcho whenever you are ready to create.

Create your account Download the app

Start a stroke.Craft something bigger.

See what the canvasactually does.

Handwriting, diagrams, and AI.One shared workspace.