RDKit MinimalLib (RDKit.js)

RDKit.js is the official JavaScript distribution of cheminformatics functionality from RDKit - a collection of cheminformatics and machine-learning software written in C++. A new NPM package is published for every RDKit release.

The core WASM module comes from RDKit's MinimalLib. MinimalLib is a C++ layer that wraps a subset of RDKit's API so it can be compiled to WebAssembly and used from JavaScript. The package is built and published directly from RDKit, while keeping JavaScript documentation at rdkitjs.com.

The package itself consists of three files:

• RDKit_minimal.js - Standard JavaScript wrapper for loading WASM modules
• RDKit_minimal.wasm - The compiled RDKit MinimalLib WASM binary
• RDKit_minimal.d.ts - TypeScript interface generated during compilation.

That means the package has zero dependencies, and if high-level component JavaScript is needed, it needs to be implemented yourself and won't be included in the general package. This is to ensure easy maintenance of the package.

Install RDKit JS

You can install it using one of the many (and growing) JavaScript package managers.

npm i @rdkit/rdkit
pnpm i @rdkit/rdkit
yarn add @rdkit/rdkit
bun add @rdkit/rdkit
...

Or use a CDN by adding this script tag to your HTML.

<script src="https://unpkg.com/@rdkit/rdkit/dist/RDKit_minimal.js"></script>

Getting Started and Loading the WASM module

See rdkitjs.com for example code, documentation, and demos.

Usually, a trick is needed to make the .wasm file available as a standalone file, but it varies from framework to framework. We have created examples for Vanilla JS, React, Vue, Angular, Svelte, Next.js, and Node.js. However, this is not RDKit-specific; it is generally how you support WASM for those frameworks.

Building the MinimalLib

Go to the MinimalLib directory, and run the following script:

scripts/build_rdkitjs.sh

The script results in a build directory with a valid JavaScript module, and includes RDKit_minimal.{js,wasm,d.ts}. To set the version of the JavaScript module use NPM_VERSION, e.g., export NPM_VERSION=1.2.3. Defaults to 0.0.0.

Set GET_SRC=clone to swap the local copy for a fresh clone from GitHub. This is relevant when you want to pass a release tag (defaults to master) and a git URL (defaults to https://github.com/rdkit/rdkit.git):

GET_SRC=clone scripts/build_rdkitjs.sh <RDKit git release tag name>
# Example: GET_SRC=clone scripts/build_rdkitjs.sh Release_2025_03_2

The full build will take 20-30 minutes to complete.

License

The binary is compiled directly from RDKit, so the license is unchanged. BSD 3-Clause.

Citation

See rdkit.com for citation. Note the version installed.