Open-source type-system software
231 open-source libraries, tools and applications tagged type-system, ranked by how closely type-system is their primary purpose, then by adoption and maintenance health. Each entry links to a page with sources, use cases and when to choose or avoid it.
231 products, primary matches first, then adoption-weighted; health v2 shown.
| Product | Health v2 | Stars | Maturity |
|---|---|---|---|
| DefinitelyTyped/DefinitelyTyped Definitely Typed is the central repository of high-quality TypeScript type definitions (.d.ts files) for thousands of popular JavaScript pa… | 67 | 51445 | active |
| jquense/yup Yup is a TypeScript schema builder for runtime value parsing and validation, letting you define object schemas that coerce, transform, and … | 68 | 23656 | stable |
| Crystal Crystal is a general-purpose, statically type-checked programming language with Ruby-inspired syntax that compiles to efficient native code… | 98 | 20446 | active |
| sindresorhus/type-fest A collection of essential TypeScript utility types that many feel should be built into the language. It is an npm package of type-only defi… | 96 | 17417 | active |
| microsoft/pyright Pyright is a full-featured, standards-based static type checker for Python built by Microsoft, designed for high performance on large codeb… | 96 | 15654 | active |
| gvergnaud/ts-pattern TS-Pattern is an exhaustive pattern matching library for TypeScript with smart type inference. It lets developers express complex branching… | 95 | 15183 | stable |
| dotansimha/graphql-code-generator GraphQL Code Generator is a plugin-based CLI tool that generates typed code from GraphQL schemas and operations (queries, mutations, subscr… | 95 | 11257 | stable |
| mac-cain13/R.swift R.swift is a code generation tool for Swift projects that generates strongly typed, autocompleted accessors for resources like images, font… | 26 | 9549 | active |
| open-circle/valibot Valibot is a modular, type-safe schema library for TypeScript that validates and parses unknown structural data at runtime while inferring … | 93 | 9021 | stable |
| PureScript PureScript is a small, strongly typed functional programming language inspired by Haskell that compiles to readable JavaScript. It features… | 70 | 8913 | active |
| mattpocock/ts-reset A 'CSS reset' for TypeScript that improves the built-in typings for common JavaScript APIs like JSON.parse, fetch's .(), .filter(Boolean), … | 52 | 8612 | stable |
| Elm The official compiler for Elm, a statically typed functional programming language designed for building reliable web applications that comp… | 94 | 7913 | stable |
| arktypeio/arktype ArkType is a TypeScript runtime validation library whose syntax mirrors TypeScript's own type system, providing 1:1 static-to-runtime type … | 94 | 7871 | active |
| supermacro/neverthrow neverthrow is a TypeScript library providing a type-safe Result type (Ok/Err) for error handling without exceptions, inspired by Rust. It i… | 56 | 7727 | active |
| ReScript ReScript is a robustly typed programming language that compiles to efficient, human-readable JavaScript, with a lightning-fast compiler too… | 93 | 7465 | active |
| millsp/ts-toolbelt ts-toolbelt is a large TypeScript type utility library offering 200+ generic type functions for computing, transforming, and creating types… | 30 | 7150 | stable |
| sinclairzx81/typebox TypeBox is a TypeScript library for building JSON Schema objects that also infer as static TypeScript types. It provides a unified runtime … | 77 | 6993 | stable |
| sqldelight/sqldelight SQLDelight is a Kotlin code generation tool that produces typesafe APIs from SQL statements. It verifies schemas, queries, and migrations a… | 86 | 6887 | active |
| gcanti/io-ts io-ts is a TypeScript library providing a runtime type system for decoding and encoding data at IO boundaries. Codecs combine static types … | 23 | 6815 | stable |
| vuejs/language-tools Vue Language Tools is the official language tooling monorepo for Vue.js, providing a VS Code extension, a language server, and the vue-tsc … | 96 | 6722 | active |
| microsoft/GSL Microsoft's implementation of the Guidelines Support Library (GSL), a header-only C++14 library of types and functions recommended by the C… | 87 | 6722 | stable |
| larastan/larastan Larastan is a PHPStan extension that adds code analysis to Laravel applications, understanding Laravel's runtime magic to find bugs before … | 99 | 6544 | active |
| orval-labs/orval Orval is a code generation tool that produces type-safe TypeScript API clients from OpenAPI v3 or Swagger v2 specifications in YAML or JSON… | 93 | 6473 | active |
| graffle-js/graffle Graffle is a minimal, extensible, type-safe GraphQL client for JavaScript and TypeScript, formerly known as graphql-request. It supports mu… | 71 | 6119 | active |
| vimeo/psalm Psalm is an open-source static analysis tool for PHP that finds type-related bugs and security vulnerabilities through type inference and t… | 98 | 5896 | active |
| piotrwitek/utility-types A TypeScript library providing a collection of utility types (like lodash for static types) that complement TypeScript's built-in mapped ty… | 56 | 5763 | stable |
| microsoft/typescript-go The staging repository for TypeScript 7.0, a native Go port of the TypeScript compiler (tsgo/tsc), offering dramatically faster type checki… | 10 | 26180 | maintenance |
| typelevel/cats Cats is a lightweight, modular, and extensible Scala library providing abstractions for functional programming, such as type classes (Funct… | 66 | 5469 | stable |
| python/typeshed Typeshed is a collection of static type stubs for the Python standard library, builtins, and many third-party packages. It provides the ann… | 75 | 5124 | active |
| Instagram/MonkeyType MonkeyType is a Python library that collects runtime types of function arguments and return values via the sys.setprofile hook, then genera… | 58 | 5007 | active |
| Scala.js Scala.js is a compiler that translates Scala code into efficient JavaScript, letting developers write type-safe applications for browsers, … | 89 | 4710 | stable |
| borgo-lang/borgo Borgo is a statically typed programming language with Rust-inspired syntax that transpiles to readable Go code. It offers algebraic data ty… | 31 | 4632 | active |
| Dhall Dhall is a programmable, non-Turing-complete configuration language with functions, types, and imports, formally specified so multiple lang… | 67 | 4488 | active |
| dry-python/returns A Python library providing typed functional programming primitives like Result, Maybe, and IO containers with full mypy support and a custo… | 87 | 4378 | active |
| unjs/magic-regexp magic-regexp is a TypeScript library providing a readable, natural-language builder for regular expressions with automatically typed captur… | 89 | 4338 | active |
| ts-essentials/ts-essentials A collection of essential TypeScript utility types for writing type-safe code, installable via npm. It provides stricter versions of built-… | 78 | 4079 | active |
| mcintyre321/OneOf OneOf is a C# library providing F#-style discriminated unions via a generic OneOf<T0,...,Tn> type with exhaustive compile-time matching. It… | 68 | 4055 | active |
| Sorbet Sorbet is a fast, gradual static type checker for Ruby, built in C++ at Stripe. It ships as a CLI (srb tc) plus a runtime gem for type anno… | 96 | 3806 | active |
| HigherOrderCO/Kind Kind is a minimal proof language and proof checker based on dependent type theory and lambda calculus, rewritten from JavaScript to Haskell… | 23 | 3760 | active |
| gvergnaud/hotscript HotScript is a TypeScript library of composable type-level functions for transforming types, offering higher-order functions like Map, Filt… | 31 | 3680 | active |
| standard-schema/standard-schema Standard Schema is a specification defining a shared interface for TypeScript schema validation libraries, so tools can accept any complian… | 76 | 3638 | active |
| DetachHead/basedpyright basedpyright is a fork of Microsoft's pyright static type checker for Python with additional type checking improvements and pylance feature… | 89 | 3627 | active |
| beartype/beartype Beartype is a pure-Python, PEP-compliant runtime type checker that validates type hints at near-real-time speed with O(1) constant-time che… | 83 | 3506 | active |
| milessabin/shapeless shapeless is a type class and dependent type based generic programming library for Scala. It enables deriving type class instances automati… | 65 | 3400 | stable |
| verus-lang/verus Verus is a verification tool for statically proving the correctness of Rust code against developer-written specifications, using SMT solver… | 96 | 3364 | active |
| adelsz/pgtyped PgTyped is a TypeScript library that generates static types for raw SQL queries against a running PostgreSQL database. It parses queries fr… | 74 | 3285 | active |
| Checked C Checked C is an extension to the C programming language that adds bounds checking and improved type safety through opt-in annotations, impl… | 23 | 3263 | active |
| F* F* is a general-purpose proof-oriented programming language combining dependent types with SMT-based proof automation and interactive theor… | 100 | 3121 | active |
| idris-lang/Idris2 Idris 2 is a purely functional programming language with first-class types and full dependent types, designed for type-driven development. … | 70 | 3094 | active |
| gql.tada gql.tada is a GraphQL document authoring library for TypeScript that infers result and variables types of queries and fragments directly in… | 95 | 2974 | active |
| Agda Agda is a dependently typed functional programming language that doubles as an interactive theorem prover based on intuitionistic type theo… | 86 | 2931 | active |
| erg-lang/erg Erg is a statically typed, Python-compatible general-purpose programming language with a powerful type system featuring dependent and refin… | 55 | 2864 | active |
| sequelize/sequelize-typescript A TypeScript library providing decorators and type-safe features for Sequelize v6, enabling class-based model definitions with @Table, @Col… | 23 | 2836 | active |
| teal-language/tl tl is the compiler and type checker for Teal, a statically-typed dialect of Lua that adds type annotations, generics, and records while com… | 74 | 2829 | active |
| ealush/vest Vest is a declarative validation framework for JavaScript/TypeScript that lets you write validation rules like unit tests using a Jest-styl… | 99 | 2668 | active |
| GORM GORM Gen is a code-generation library built on top of the GORM ORM for Go. It generates type-safe DAO APIs and query DSL code from database… | 92 | 2560 | active |
| tsdjs/tsd tsd is a CLI tool and library for testing TypeScript type definitions (.d.ts files). It statically analyzes .test-d.ts files containing ass… | 38 | 2553 | active |
| ardalis/SmartEnum A C# base class library for creating strongly-typed enum alternatives with behavior, lookup by name or value, and rich integration support.… | 55 | 2443 | stable |
| ariebovenberg/whenever Whenever is a Python library providing type-safe datetime and timezone handling that prevents naive/aware mixing at the type level and corr… | 94 | 2406 | active |
| obsidianmd/obsidian-api TypeScript type definitions for the Obsidian plugin API, maintained by the Obsidian team. It enables developers to build Obsidian plugins w… | 76 | 2333 | active |
| typegoose/typegoose Typegoose is a TypeScript library that lets you define Mongoose models using TypeScript classes with decorators, eliminating the need to ma… | 97 | 2311 | active |
| Mokshit06/typewind Typewind is a typesafe, zero-runtime wrapper around Tailwind CSS that lets you write Tailwind classes as TypeScript expressions via a `tw` … | 53 | 2290 | active |
| posva/unplugin-vue-router A build-time unplugin that generates Vue Router routes from your file system structure with full TypeScript type safety. It supports Vite, … | 10 | 2235 | active |
| symfony/property-info A Symfony PHP component that extracts information about PHP class properties (types, visibility, descriptions, accessibility) from metadata… | 93 | 2220 | stable |
| dtolnay/async-trait A Rust attribute macro crate that makes async functions in traits work with dyn Trait (dynamic dispatch) via type erasure. It bridges the g… | 94 | 2207 | stable |
| ruby/rbs RBS is the type signature language for Ruby, letting developers describe class, module, method, and variable types in .rbs files. It ships … | 97 | 2183 | active |
| microsoft/pylance-release Pylance is Microsoft's fast, feature-rich Python language server extension for Visual Studio Code, providing IntelliSense, auto-imports, di… | 99 | 2133 | active |
| Closure Compiler Google Closure Compiler is a JavaScript-to-JavaScript compiler that parses, analyzes, and optimizes code by removing dead code, rewriting, … | 77 | 7693 | maintenance |
| TypeStrong/fork-ts-checker-webpack-plugin A Webpack plugin that runs TypeScript type checking in a separate worker process to speed up builds. It supports project references, increm… | 61 | 2000 | active |
| typeddjango/django-stubs A collection of PEP-484/PEP-561 type stubs plus a custom mypy plugin that provides precise static typing and type inference for the Django … | 98 | 1978 | active |
| typedgrammar/typed-japanese Typed Japanese is a TypeScript type-level library that encodes Japanese grammar rules as a DSL, letting users write and verify grammaticall… | 56 | 1945 | active |
| patrick-kidger/jaxtyping A Python library providing type annotations and runtime type-checking for the shape and dtype of arrays and tensors in JAX, PyTorch, NumPy,… | 90 | 1873 | active |
| alexreardon/tiny-invariant A tiny, zero-dependency invariant assertion function for JavaScript and TypeScript that throws when a condition is falsy. It also narrows t… | 23 | 1863 | stable |
| kubb-labs/kubb Kubb is a meta framework for code generation that turns OpenAPI/Swagger specifications into type-safe TypeScript code via a plugin-based pi… | 95 | 1825 | active |
| frenic/csstype CSSType provides strict TypeScript and Flow type definitions for CSS properties and values, generated from MDN data. It enables autocomplet… | 53 | 1816 | stable |
| sindresorhus/is A TypeScript library for checking the type of values at runtime, with type guards and assertions. It provides a simple API like `is.string(… | 85 | 1798 | active |
| agronholm/typeguard Typeguard is a Python library that performs run-time type checking based on PEP 484 type annotations, complementing static type checkers. I… | 90 | 1792 | active |
| ThomasAribart/json-schema-to-ts A TypeScript library that statically infers TypeScript types from JSON schemas via a FromSchema type utility, eliminating duplicate type de… | 56 | 1783 | active |
| coalton-lang/coalton Coalton is a statically typed functional programming language embedded in Common Lisp, drawing ideas from Haskell, Scheme, and OCaml. It co… | 92 | 1779 | active |
| greyblake/nutype Nutype is a Rust procedural macro that enhances the newtype pattern with built-in sanitization and validation constraints. It guarantees th… | 88 | 1776 | active |
| andrewlock/StronglyTypedId A Roslyn-powered compile-time source generator for .NET that creates strongly-typed ID types from a simple attribute, eliminating boilerpla… | 32 | 1756 | active |
| fthomas/refined refined is a Scala library for refinement types, letting you attach type-level predicates to base types so value constraints are checked at… | 81 | 1732 | active |
| hashintel/hash HASH is an open-source, multi-tenant platform for building self-maintaining knowledge graphs and process graphs, powered by the hgres graph… | 97 | 1675 | active |
| foonathan/type_safe A C++ library providing zero-overhead abstractions that leverage the type system to prevent bugs at compile time. It offers improved wrappe… | 40 | 1650 | active |
| fabien0102/ts-to-zod ts-to-zod is a CLI tool that generates Zod validation schemas from TypeScript types and interfaces. It verifies that generated schemas are … | 74 | 1640 | active |
| pointfreeco/swift-tagged A Swift library providing a Tagged wrapper type that distinguishes otherwise interchangeable raw values (like Int or String) at compile tim… | 43 | 1634 | stable |
| gigobyte/purify Purify is a functional programming library for TypeScript providing algebraic data types like Maybe, Either, and Result, plus runtime type … | 57 | 1608 | active |
| ts-safeql/safeql SafeQL is an ESLint plugin that validates raw SQL queries against a live PostgreSQL schema and automatically infers TypeScript types for qu… | 82 | 1569 | active |
| Chrome DevTools Protocol The official repository for the Chrome DevTools Protocol (CDP), providing protocol definitions, documentation, and TypeScript type definiti… | 76 | 1569 | active |
| hirrolot/datatype99 A single-header C99 library providing safe algebraic data types (sum types/tagged unions) with exhaustive pattern matching and compile-time… | 24 | 1508 | stable |
| SteveDunn/Vogen Vogen is a C# source generator and analyzer that converts primitives into strongly-typed value objects representing domain concepts. It emi… | 94 | 1505 | active |
| Steep Steep is a static type checker for Ruby based on gradual typing, using RBS signature files and inline annotations. It is distributed as a R… | 97 | 1492 | active |
| mpusz/mp-units mp-units is a modern C++20/23/26 library providing compile-time-safe quantities and units of measurement, built on the ISO 80000 Internatio… | 71 | 1480 | active |
| sveltejs/language-tools Svelte Language Tools provides a Language Server Protocol implementation for Svelte files, powering the official VS Code extension and plug… | 95 | 1446 | active |
| dry-rb/dry-validation dry-validation is a Ruby library for data validation using type-safe schemas and composable rules. It supports input coercion, nested data,… | 78 | 1423 | active |
| vultix/ts-results A TypeScript library implementing Rust's Result and Option types, bringing compile-time error checking and explicit optional values to Type… | 32 | 1409 | stable |
| HoTT/Coq-HoTT A Coq library for Homotopy Type Theory, interpreting Martin-Löf's intensional type theory into abstract homotopy theory. It provides formal… | 82 | 1405 | active |
| pytype Pytype is a static type analyzer for Python that checks and infers types without requiring type annotations, using inference rather than gr… | 10 | 5036 | maintenance |
| JetBrains/phpstorm-stubs A collection of syntactically correct PHP stub files describing the signatures, constants, and PHPDoc annotations of PHP core and standard … | 87 | 1392 | active |
| mrmckeb/typescript-plugin-css-modules A TypeScript language service plugin that provides IDE support (autocomplete, type checking, go-to-definition) for CSS Modules imports. It … | 62 | 1392 | stable |
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