# @canvas-js/core > This package exports a `Canvas` class that can be used to manually instantiate Canvas applications. Latest version **0.16.1** (published 2025-07-30) · 0 weekly downloads ## Install ```sh npm install @canvas-js/core pnpm add @canvas-js/core yarn add @canvas-js/core bun add @canvas-js/core ``` ## Health **Score 35/100 (D)** — status: maintenance-mode. Positive: has types; esm support; no vulnerabilities. Warnings: low downloads; pre 1.0. Negative: stale; low maintenance score. ## Facts | | | |---|---| | Version | 0.16.1 | | Published | 2025-07-30 | | First published | 2022-05-16 | | Weekly downloads | 0 | | TypeScript types | bundled | | Module format | ESM + CommonJS | | Node | >=22.0.0 | | Dependencies | 43 | | Unpacked size | 159.6 KB | | Known vulnerabilities | 0 | | Install scripts | no | | Author | Canvas Technologies, Inc. | | Maintainers | joelg, raykyri, rjwebb | ## Links - npm: https://www.npmjs.com/package/@canvas-js/core - npm.io page: https://npm.io/package/@canvas-js/core ## Dependencies (43) - [pg](https://npm.io/package/pg.md) ^8.15.6 - [ws](https://npm.io/package/ws.md) ^8.18.2 - [cors](https://npm.io/package/cors.md) ^2.8.5 - [chalk](https://npm.io/package/chalk.md) ^5.4.1 - [ethers](https://npm.io/package/ethers.md) ^6.13.5 - [esbuild](https://npm.io/package/esbuild.md) ^0.25.5 - [express](https://npm.io/package/express.md) ^5.1.0 - [p-defer](https://npm.io/package/p-defer.md) ^4.0.1 - [p-queue](https://npm.io/package/p-queue.md) ^8.1.0 - [@types/ws](https://npm.io/package/@types/ws.md) ^8.5.14 - [any-signal](https://npm.io/package/any-signal.md) ^4.1.1 - [@types/cors](https://npm.io/package/@types/cors.md) ^2.8.17 - [prom-client](https://npm.io/package/prom-client.md) ^15.1.2 - [uint8arrays](https://npm.io/package/uint8arrays.md) ^5.1.0 - [@ipld/schema](https://npm.io/package/@ipld/schema.md) ^6.0.6 - [esbuild-wasm](https://npm.io/package/esbuild-wasm.md) ^0.25.1 - [multiformats](https://npm.io/package/multiformats.md) ^13.3.7 - [prng-xoshiro](https://npm.io/package/prng-xoshiro.md) ^1.0.1 - [@canvas-js/vm](https://npm.io/package/@canvas-js/vm.md) 0.16.1 - [@noble/curves](https://npm.io/package/@noble/curves.md) ^1.9.2 - [@noble/hashes](https://npm.io/package/@noble/hashes.md) ^1.8.0 - [@ipld/dag-cbor](https://npm.io/package/@ipld/dag-cbor.md) ^9.2.4 - [@ipld/dag-json](https://npm.io/package/@ipld/dag-json.md) ^10.2.5 - [@libp2p/logger](https://npm.io/package/@libp2p/logger.md) ^5.1.13 - [@types/express](https://npm.io/package/@types/express.md) ^5.0.3 - [uint8arraylist](https://npm.io/package/uint8arraylist.md) ^2.4.8 - [@libp2p/peer-id](https://npm.io/package/@libp2p/peer-id.md) ^5.1.6 - [aggregate-error](https://npm.io/package/aggregate-error.md) ^5.0.0 - [@canvas-js/utils](https://npm.io/package/@canvas-js/utils.md) 1.0.0 - [@libp2p/interface](https://npm.io/package/@libp2p/interface.md) ^2.10.3 - [http-status-codes](https://npm.io/package/http-status-codes.md) ^2.3.0 - [@canvas-js/modeldb](https://npm.io/package/@canvas-js/modeldb.md) 0.16.1 - [abortable-iterator](https://npm.io/package/abortable-iterator.md) ^5.0.1 - [quickjs-emscripten](https://npm.io/package/quickjs-emscripten.md) ^0.31.0 - [@canvas-js/gossiplog](https://npm.io/package/@canvas-js/gossiplog.md) 0.16.1 - [@canvas-js/interfaces](https://npm.io/package/@canvas-js/interfaces.md) 0.16.1 - [@canvas-js/modeldb-pg](https://npm.io/package/@canvas-js/modeldb-pg.md) 0.16.1 - [@canvas-js/signatures](https://npm.io/package/@canvas-js/signatures.md) 0.16.1 - [@canvas-js/modeldb-idb](https://npm.io/package/@canvas-js/modeldb-idb.md) 0.16.1 - [@multiformats/multiaddr](https://npm.io/package/@multiformats/multiaddr.md) ^12.4.1 - [@canvas-js/modeldb-sqlite](https://npm.io/package/@canvas-js/modeldb-sqlite.md) 0.16.1 - [@canvas-js/signer-ethereum](https://npm.io/package/@canvas-js/signer-ethereum.md) 0.16.1 - [@canvas-js/modeldb-durable-objects](https://npm.io/package/@canvas-js/modeldb-durable-objects.md) 0.16.1 ## Recent versions - 0.16.1 (latest) — 2025-07-30 - 0.16.0-next.9 (next) — 2025-07-13 - 0.10.0-beta.3 (beta) — 2024-06-27 - 0.10.0-alpha.1 (alpha) — 2024-05-21 - 0.16.0 — 2025-07-08 - 0.16.0-next.8 — 2025-06-26 - 0.16.0-next.7 — 2025-06-25 - 0.16.0-next.6 — 2025-06-25 - 0.16.0-next.5 — 2025-06-18 - 0.16.0-next.4 — 2025-06-18 - 0.16.0-next.3 — 2025-06-13 - 0.16.0-next.2 — 2025-06-13 - 0.16.0-next.1 — 2025-06-13 - 0.16.0-next.0 — 2025-06-13 - 0.15.2-next.0 — 2025-06-11 - … 248 more at https://npm.io/package/@canvas-js/core/versions ## README # @canvas-js/core This package exports a `Canvas` class that can be used to manually instantiate Canvas applications. Use this package directly if you want fine-grained control over when an application is started/stopped. Otherwise, you can use `useCanvas` in `@canvas-js/hooks`, which has the same API, but handles initialization inside React for you. ## Table of Contents - [Installation](#installation) - [Usage](#usage) - [API](#api) ## Installation ``` $ npm i @canvas-js/core ``` ## How it works Under the hood, each `Canvas` application replicates and executes a log of signed actions, sourced from GossipLog, with read/write access to a ModelDB database. Each application accepts several arguments: - `contract` takes a class that extends `Contract`, or a string containing a JS module which exports a default class that extends `Contract`. - `topic` takes a string - `snapshot` (optional) takes a `Snapshot` object which provides initial database contents for the application. - `signers` (optional) takes an array of signers, which allows different auth methods to be added to the application. Use `await Canvas.initialize` to start the application. (For synchronous initialization, see CanvasLoadable.ts.) To connect the application to other sync peers, use `app.connect()` to start a WebSocket connection, or `app.listen()` to listen for WebSocket connections from the server. Or, use `app.startLibp2p()` to start a libp2p node. After starting the application, you can use `app.actions` to access each of the actions that you have defined. Action calls will be signed and proxied to the contract. ```ts import { Canvas, Contract } from "@canvas-js/core" class Chat extends Contract { static models = { posts: { id: "primary", user: "string", content: "string", updated_at: "integer", }, } async createPost(content: string) { const { id, chain, address, timestamp, db } = this const user = [chain, address].join(":") await db.set("posts", { id, user, content, updated_at: timestamp }) } async deletePost(postId: string) { const { chain, address, db } = this const post = await db.get("posts", postId) if (post === null) { return } const user = [chain, address].join(":") if (post.user !== user) { throw new Error("not authorized") } await db.delete("posts", postId) } } const app = await Canvas.initialize({ topic: "example.xyz", contract: Chat, }) await app.actions.createPost("hello world!") const results = await app.db.query("posts", {}) // [ // { // id: '09p5qn7affkhtbflscr663tet8ddeu41', // user: 'did:pkh:eip155:1:0x79c5158f81ebb0c2bcF877E9e1813aed2Eb652B7', // content: 'hello world!', // updated_at: 1698339861041 // } // ] ``` ## API <<< @/../packages/core/src/types.ts --- _Source: https://npm.io/package/@canvas-js/core · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._