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Optimal is a system for building and validating any value with typed schemas, and first-class support for defined object structures, like options objects, configuration files, validation fields, and many more. Optimal aims to provide a powerful API, with high performance, the lowest possible filesize, and TypeScript-first support.

// Import schemas to build validators withimport { array, string, number, optimal } from 'optimal';
// Define and validate values with individual schemasconst maxSizeSchema = number().positive().lte(10000);
// Or define an explicit shaped blueprintconst schema = optimal({  name: string().notEmpty(),  include: array().of(string()),  exclude: array().of(string()),  maxSize: maxSizeSchema});
// Pass a full or partial object to validateconst options = schema.validate({ name: 'Optimal' });
// Which validates, builds, and returns the following object{  name: 'Optimal',  include: [],  exclude: [],  maxSize: 10000,}


  • Zero dependencies, with a tree-shakable API.
  • Powerful inferrence using a TypeScript first design.
  • Runs in both Node.js and the browser.
  • Smallest filesize: 5kB minified and gzipped!
  • Immutable & fluent schema builder pattern.
  • Recursively builds and validates nested structures.
  • Supports common data types.
  • Autofills missing or undefined fields with default values.
  • Allows or restricts unknown fields.
  • Mark fields as nullable, undefinable, optional, or required.
  • Handles logical operators AND, OR, and XOR.


  • Node v12.17 (server)
  • Edge, Chrome, Firefox, Safari (browser)


Install optimal with yarn or npm.

yarn add optimal

If using TypeScript, we highly encourage the use of strict mode. We cannot guarantee types will infer correctly otherwise.

{    "compilerOptions": {        "strict": true    }}