# level > Universal abstract-level database for Node.js and browsers Latest version **10.0.0** (published 2025-04-20) · MIT license · 0 weekly downloads ## Install ```sh npm install level pnpm add level yarn add level bun add level ``` ## Health **Score 45/100 (D)** — status: stable. Positive: has types; no vulnerabilities; high quality score. Warnings: low downloads; no esm support. Negative: stale. ## Facts | | | |---|---| | Version | 10.0.0 | | Published | 2025-04-20 | | First published | 2013-04-15 | | Weekly downloads | 0 | | License | MIT | | TypeScript types | bundled | | Module format | CommonJS | | Node | >=18 | | Dependencies | 3 | | Unpacked size | 52.1 KB | | Known vulnerabilities | 0 | | Install scripts | no | | GitHub stars | 1673 | | Maintainers | vweevers, rvagg, ralphtheninja | | Keywords | level, leveldb, stream, database, db, store, storage, json | ## Links - npm: https://www.npmjs.com/package/level - Repository: https://github.com/Level/level - Issues: https://github.com/Level/level/issues - Funding: https://opencollective.com/level - npm.io page: https://npm.io/package/level ## Dependencies (3) - [browser-level](https://npm.io/package/browser-level.md) ^3.0.0 - [classic-level](https://npm.io/package/classic-level.md) ^3.0.0 - [abstract-level](https://npm.io/package/abstract-level.md) ^3.1.0 ## Alternatives - [@mapbox/jsonlint-lines-primitives](https://npm.io/package/@mapbox/jsonlint-lines-primitives.md) — 5.3M weekly downloads - [reftools](https://npm.io/package/reftools.md) — 3.5M weekly downloads - [@hey-api/openapi-ts](https://npm.io/package/@hey-api/openapi-ts.md) — 3.5M weekly downloads - [@mapbox/geojson-rewind](https://npm.io/package/@mapbox/geojson-rewind.md) — 2.4M weekly downloads - [turbo-stream](https://npm.io/package/turbo-stream.md) — 1.7M weekly downloads ## Recent versions - 10.0.0 (latest) — 2025-04-20 - 5.0.0-0 (next) — 2018-12-31 - 9.0.0 — 2024-12-01 - 8.0.1 — 2024-01-27 - 8.0.0 — 2022-03-25 - 7.0.1 — 2021-10-02 - 7.0.0 — 2021-04-17 - 6.0.1 — 2020-03-04 - 6.0.0 — 2019-10-19 - 5.0.1 — 2019-03-29 - 5.0.0 — 2019-03-29 - 4.0.0 — 2018-05-23 - 3.0.2 — 2018-05-23 - 3.0.1 — 2018-05-05 - 3.0.0 — 2018-02-17 - … 32 more at https://npm.io/package/level/versions ## README # level **Universal [`abstract-level`](https://github.com/Level/abstract-level) database for Node.js and browsers.** This is a convenience package that exports [`classic-level`](https://github.com/Level/classic-level) in Node.js and [`browser-level`](https://github.com/Level/browser-level) in browsers, making it an ideal entry point to start creating lexicographically sorted key-value databases. > :pushpin: Which module should I use? What is `abstract-level`? Head over to the [FAQ](https://github.com/Level/community#faq). [![level badge][level-badge]](https://github.com/Level/awesome) [![npm](https://img.shields.io/npm/v/level.svg)](https://www.npmjs.com/package/level) [![Node version](https://img.shields.io/node/v/level.svg)](https://www.npmjs.com/package/level) [![Test](https://img.shields.io/github/actions/workflow/status/Level/level/test.yml?branch=master&label=test)](https://github.com/Level/level/actions/workflows/test.yml) [![Coverage](https://img.shields.io/codecov/c/github/Level/level?label=\&logo=codecov\&logoColor=fff)](https://codecov.io/gh/Level/level) [![Standard](https://img.shields.io/badge/standard-informational?logo=javascript\&logoColor=fff)](https://standardjs.com) [![Common Changelog](https://common-changelog.org/badge.svg)](https://common-changelog.org) [![Community](https://img.shields.io/badge/community-join-%2370B99E?logo=github)](https://github.com/Level/community/issues) [![Donate](https://img.shields.io/badge/donate-orange?logo=open-collective\&logoColor=fff)](https://opencollective.com/level) ## Usage _If you are upgrading: please see [`UPGRADING.md`](UPGRADING.md)._ ```js const { Level } = require('level') // Create a database const db = new Level('example', { valueEncoding: 'json' }) // Add an entry with key 'a' and value 1 await db.put('a', 1) // Add multiple entries await db.batch([{ type: 'put', key: 'b', value: 2 }]) // Get value of key 'a': 1 const value = await db.get('a') // Iterate entries with keys that are greater than 'a' for await (const [key, value] of db.iterator({ gt: 'a' })) { console.log(value) // 2 } ``` TypeScript type declarations are included and cover the methods that are common between `classic-level` and `browser-level`. Usage from TypeScript requires generic type parameters.
TypeScript example ```ts // Specify types of keys and values (any, in the case of json). // The generic type parameters default to Level. const db = new Level('./db', { valueEncoding: 'json' }) // All relevant methods then use those types await db.put('a', { x: 123 }) // Specify different types when overriding encoding per operation await db.get('a', { valueEncoding: 'utf8' }) // Though in some cases TypeScript can infer them await db.get('a', { valueEncoding: db.valueEncoding('utf8') }) // It works the same for sublevels const abc = db.sublevel('abc') const xyz = db.sublevel('xyz', { valueEncoding: 'json' }) ```
## Install With [npm](https://npmjs.org) do: ```bash npm install level ``` For use in browsers, this package is best used with [`browserify`](https://github.com/browserify/browserify), [`webpack`](https://webpack.js.org/), [`rollup`](https://rollupjs.org/) or similar bundlers. For a quick start, visit [`browserify-starter`](https://github.com/Level/browserify-starter) or [`webpack-starter`](https://github.com/Level/webpack-starter). ## Supported Platforms At the time of writing, `level` works in Node.js 18+ and Electron 30+ on Linux, Mac OS and Windows, including any future Node.js and Electron release thanks to [Node-API](https://nodejs.org/api/n-api.html), including ARM platforms like Raspberry Pi and Android, as well as in Chromium, Firefox and Safari. For details, see [Supported Platforms](https://github.com/Level/classic-level#supported-platforms) of `classic-level` and [Browser Support](https://github.com/Level/browser-level#browser-support) of `browser-level`. Binary keys and values are supported across the board. ## API The API of `level` follows that of [`abstract-level`](https://github.com/Level/abstract-level). For additional options and methods specific to [`classic-level`](https://github.com/Level/classic-level) or [`browser-level`](https://github.com/Level/browser-level), please see their respective READMEs. The documentation below only covers the common constructor. ### `db = new Level(location[, options])` Create a new database or open an existing database. The `location` argument must be a directory path (relative or absolute) where LevelDB will store its files, or in browsers, the name of the [`IDBDatabase`](https://developer.mozilla.org/en-US/docs/Web/API/IDBDatabase) to be opened. ## Contributing [`Level/level`](https://github.com/Level/level) is an **OPEN Open Source Project**. This means that: > Individuals making significant and valuable contributions are given commit-access to the project to contribute as they see fit. This project is more like an open wiki than a standard guarded open source project. See the [Contribution Guide](https://github.com/Level/community/blob/master/CONTRIBUTING.md) for more details. ## Donate Support us with a monthly donation on [Open Collective](https://opencollective.com/level) and help us continue our work. ## License [MIT](LICENSE) [level-badge]: https://leveljs.org/img/badge.svg --- _Source: https://npm.io/package/level · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._