Free
Jest
Open SourceUnit & Component · Testing
Delightful JavaScript testing framework with snapshots and mocks.
unittestingjavascript
Browse the complete directory — use filters to narrow down.
Unit & Component · Testing
Delightful JavaScript testing framework with snapshots and mocks.
State & Forms · Frontend
Primitive and flexible atomic state management for React.
CLI Tools · Development Environment
Lightweight command-line JSON processor.
JSON · Data Formats
Advanced JSON editor with tree view, query, transform and diff.
JSON · Data Formats
Format, validate, minify and view JSON online.
JSON · Data Formats
Beautiful, shareable JSON viewer with previews for many data types.
JSON · Data Formats
Official site of the JSON Schema specification, with tools and validators.
Mocks & Fakes · Testing
Get a full fake REST API from a JSON file in seconds.
JSON · Data Formats
The classic JSON validator and formatter.
API Mocking · API Tools
Free fake REST API for prototyping and testing.
Programming Languages
High-performance language for technical and scientific computing.
Unit & Component · Testing
The standard testing framework for the JVM: annotation-driven unit tests for Java and Kotlin.
Notebooks & Data Science · Data & Analytics
The standard interactive notebooks for data science and ML.
CLI Tools · Development Environment
Handy, syntax-clean command runner for project-specific recipes.
JWT · Encoding & Decoding
The official JSON Web Token site: decode, debug and find libraries.
Orchestration · DevOps
Terminal UI to interact with and manage Kubernetes clusters.
Penetration Testing · Security
Debian-based Linux distribution shipping 600+ preinstalled penetration testing and forensics tools.
Screenshots · Image & Media
Beautiful open-source screen recorder for macOS — captures, trims and exports GIFs/MP4s with plugins.
Authentication · API Tools
Open-source identity and access management with SSO and SAML.
Terminals & Shells · Development Environment
Fast, GPU-based terminal with graphics support and layouts.
Programming Languages
Official Kotlin language site: docs, playground and standard library reference.
Cross-Platform · Mobile Development
Share Kotlin code across iOS, Android, desktop and web.
Orchestration · DevOps
Template-free customization of Kubernetes YAML manifests.
ORMs · Backend
Type-safe SQL query builder for TypeScript, no DSL required.