Ross ROSS = Recommend OSS · open-source software intelligence for agents

function: type-system

240 products, primary matches first, then adoption-weighted; health v2 shown.

ProductHealth v2StarsMaturity
rust-lang/rust
The official Rust monorepo containing the rustc compiler, standard library, and documentation for the Rust programming language. Rust is a …
99116191stable
microsoft/TypeScript
TypeScript is a strongly typed superset of JavaScript that adds optional static types and compiles down to clean, standards-based JavaScrip…
95110715stable
DefinitelyTyped/DefinitelyTyped
Definitely Typed is the central repository of high-quality TypeScript type definitions (.d.ts files) for thousands of popular JavaScript pa…
6751407active
colinhacks/zod
Zod is a TypeScript-first schema validation library for defining and validating data structures at runtime with static type inference. It h…
8943535stable
jquense/yup
Yup is a TypeScript schema builder for runtime value parsing and validation, letting you define object schemas that coerce, transform, and …
6723671stable
facebook/flow
Flow is a static type checker for JavaScript, now a typed dialect of JavaScript written in Rust. It catches type errors via annotations and…
9522279active
python/mypy
Mypy is an optional static type checker for Python that validates type hints (PEP 484) in your code. It catches type errors before runtime …
7720605stable
crystal-lang/crystal
Crystal is a general-purpose, statically type-checked programming language with Ruby-inspired syntax that compiles to efficient native code…
9720388active
astral-sh/ty
ty is an extremely fast Python type checker and language server written in Rust, backed by Astral (creators of Ruff and uv). It provides ri…
8219562active
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…
9617381active
microsoft/pyright
Pyright is a full-featured, standards-based static type checker for Python built by Microsoft, designed for high performance on large codeb…
9815597active
gvergnaud/ts-pattern
TS-Pattern is an exhaustive pattern matching library for TypeScript with smart type inference. It lets developers express complex branching…
7815137stable
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…
9511264stable
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…
409560active
open-circle/valibot
Valibot is a modular, type-safe schema library for TypeScript that validates and parses unknown structural data at runtime while inferring …
928962stable
PureScript
PureScript is a small, strongly typed functional programming language inspired by Haskell that compiles to readable JavaScript. It features…
768901active
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), …
558592stable
Elm
The official compiler for Elm, a statically typed functional programming language designed for building reliable web applications that comp…
867886stable
arktypeio/arktype
ArkType is a TypeScript runtime validation library whose syntax mirrors TypeScript's own type system, providing 1:1 static-to-runtime type …
897848active
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…
647689active
ReScript
ReScript is a robustly typed programming language that compiles to efficient, human-readable JavaScript, with a lightning-fast compiler too…
957435active
millsp/ts-toolbelt
ts-toolbelt is a large TypeScript type utility library offering 200+ generic type functions for computing, transforming, and creating types…
347152stable
sinclairzx81/typebox
TypeBox is a TypeScript library for building JSON Schema objects that also infer as static TypeScript types. It provides a unified runtime …
776929stable
sqldelight/sqldelight
SQLDelight is a Kotlin code generation tool that produces typesafe APIs from SQL statements. It verifies schemas, queries, and migrations a…
826865active
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 …
236808stable
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 …
996714active
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…
916710stable
larastan/larastan
Larastan is a PHPStan extension that adds code analysis to Laravel applications, understanding Laravel's runtime magic to find bugs before …
956493active
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…
956396active
graffle-js/graffle
Graffle is a minimal, extensible, type-safe GraphQL client for JavaScript and TypeScript, formerly known as graphql-request. It supports mu…
776116active
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…
885884active
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…
595763stable
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…
7626225maintenance
typelevel/cats
Cats is a lightweight, modular, and extensible Scala library providing abstractions for functional programming, such as type classes (Funct…
675456stable
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…
775114active
Instagram/MonkeyType
MonkeyType is a Python library that collects runtime types of function arguments and return values via the sys.setprofile hook, then genera…
624997active
scala-js/scala-js
Scala.js is a compiler that translates Scala code into efficient JavaScript, letting developers write type-safe applications for browsers, …
914710stable
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…
314639active
dhall-lang/dhall-lang
Dhall is a programmable, non-Turing-complete configuration language with functions, types, and imports, formally specified so multiple lang…
674475active
dry-python/returns
A Python library providing typed functional programming primitives like Result, Maybe, and IO containers with full mypy support and a custo…
904355active
unjs/magic-regexp
magic-regexp is a TypeScript library providing a readable, natural-language builder for regular expressions with automatically typed captur…
824335active
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-…
844075active
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…
714054active
sorbet/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…
953797active
HigherOrderCO/Kind
Kind is a minimal proof language and proof checker based on dependent type theory and lambda calculus, rewritten from JavaScript to Haskell…
243766active
gvergnaud/hotscript
HotScript is a TypeScript library of composable type-level functions for transforming types, offering higher-order functions like Map, Filt…
313677active
standard-schema/standard-schema
Standard Schema is a specification defining a shared interface for TypeScript schema validation libraries, so tools can accept any complian…
753598active
DetachHead/basedpyright
basedpyright is a fork of Microsoft's pyright static type checker for Python with additional type checking improvements and pylance feature…
883557active
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…
863486active
milessabin/shapeless
shapeless is a type class and dependent type based generic programming library for Scala. It enables deriving type class instances automati…
673402stable
adelsz/pgtyped
PgTyped is a TypeScript library that generates static types for raw SQL queries against a running PostgreSQL database. It parses queries fr…
743276active
checkedc/checkedc
Checked C is an extension to the C programming language that adds bounds checking and improved type safety through opt-in annotations, impl…
233255active
FStarLang/FStar
F* is a general-purpose proof-oriented programming language combining dependent types with SMT-based proof automation and interactive theor…
993100active
idris-lang/Idris2
Idris 2 is a purely functional programming language with first-class types and full dependent types, designed for type-driven development. …
723048active
0no-co/gql.tada
gql.tada is a GraphQL document authoring library for TypeScript that infers result and variables types of queries and fragments directly in…
942968active
agda/agda
Agda is a dependently typed functional programming language that doubles as an interactive theorem prover based on intuitionistic type theo…
672920active
verus-lang/verus
Verus is a verification tool for statically proving the correctness of Rust code against developer-written specifications, using SMT solver…
952890active
erg-lang/erg
Erg is a statically typed, Python-compatible general-purpose programming language with a powerful type system featuring dependent and refin…
592860active
sequelize/sequelize-typescript
A TypeScript library providing decorators and type-safe features for Sequelize v6, enabling class-based model definitions with @Table, @Col…
232839active
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…
782814active
ealush/vest
Vest is a declarative validation framework for JavaScript/TypeScript that lets you write validation rules like unit tests using a Jest-styl…
922665active
go-gorm/gen
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…
952558active
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…
422557active
ardalis/SmartEnum
A C# base class library for creating strongly-typed enum alternatives with behavior, lookup by name or value, and rich integration support.…
652440stable
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…
932398active
obsidianmd/obsidian-api
TypeScript type definitions for the Obsidian plugin API, maintained by the Obsidian team. It enables developers to build Obsidian plugins w…
742315active
typegoose/typegoose
Typegoose is a TypeScript library that lets you define Mongoose models using TypeScript classes with decorators, eliminating the need to ma…
962311active
Mokshit06/typewind
Typewind is a typesafe, zero-runtime wrapper around Tailwind CSS that lets you write Tailwind classes as TypeScript expressions via a `tw` …
562288active
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, …
102240active
symfony/property-info
A Symfony PHP component that extracts information about PHP class properties (types, visibility, descriptions, accessibility) from metadata…
992221stable
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…
982186stable
ruby/rbs
RBS is the type signature language for Ruby, letting developers describe class, module, method, and variable types in .rbs files. It ships …
992174active
microsoft/pylance-release
Pylance is Microsoft's fast, feature-rich Python language server extension for Visual Studio Code, providing IntelliSense, auto-imports, di…
972115active
google/closure-compiler
Google Closure Compiler is a JavaScript-to-JavaScript compiler that parses, analyzes, and optimizes code by removing dead code, rewriting, …
777676maintenance
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…
651999active
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 …
981970active
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…
591946active
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…
231863stable
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,…
951859active
frenic/csstype
CSSType provides strict TypeScript and Flow type definitions for CSS properties and values, generated from MDN data. It enables autocomplet…
571814stable
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(…
811791active
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…
941789active
agronholm/typeguard
Typeguard is a Python library that performs run-time type checking based on PEP 484 type annotations, complementing static type checkers. I…
911780active
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…
591778active
greyblake/nutype
Nutype is a Rust procedural macro that enhances the newtype pattern with built-in sanitization and validation constraints. It guarantees th…
801761active
coalton-lang/coalton
Coalton is a statically typed functional programming language embedded in Common Lisp, drawing ideas from Haskell, Scheme, and OCaml. It co…
931752active
andrewlock/StronglyTypedId
A Roslyn-powered compile-time source generator for .NET that creates strongly-typed ID types from a simple attribute, eliminating boilerpla…
351752active
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…
851733active
hashintel/hash
HASH is an open-source, multi-tenant platform for building self-maintaining knowledge graphs and process graphs, powered by the hgres graph…
991649active
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…
441649active
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 …
801635active
pointfreeco/swift-tagged
A Swift library providing a Tagged wrapper type that distinguishes otherwise interchangeable raw values (like Int or String) at compile tim…
461629stable
gigobyte/purify
Purify is a functional programming library for TypeScript providing algebraic data types like Maybe, Either, and Result, plus runtime type …
631603active
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…
881561active
ChromeDevTools/devtools-protocol
The official repository for the Chrome DevTools Protocol (CDP), providing protocol definitions, documentation, and TypeScript type definiti…
771537active
hirrolot/datatype99
A single-header C99 library providing safe algebraic data types (sum types/tagged unions) with exhaustive pattern matching and compile-time…
281508stable
SteveDunn/Vogen
Vogen is a C# source generator and analyzer that converts primitives into strongly-typed value objects representing domain concepts. It emi…
971492active
soutaro/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…
791488active
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…
751465active
sveltejs/language-tools
Svelte Language Tools provides a Language Server Protocol implementation for Svelte files, powering the official VS Code extension and plug…
941442active

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