Freemium
Polar
Open SourcePayments · API Tools
Open-source payments and monetization for developers — checkouts, subscriptions and license keys, MoR model.
paymentsopen-sourcesubscriptionssaas
Browse the complete directory — use filters to narrow down.
Payments · API Tools
Open-source payments and monetization for developers — checkouts, subscriptions and license keys, MoR model.
Containers · DevOps
Self-hosted GUI for managing Docker and Kubernetes environments.
Design Systems · Design & Prototyping
GitHub's design system with React components and tokens.
Logs & Metrics · Monitoring & Observability
The standard open-source metrics collection and alerting toolkit.
Agent & LLM Frameworks · AI for Developers
The most comprehensive open guide to prompting techniques.
References · Documentation & Learning
The largest curated directory of free public APIs — 1,400+ entries across 40 categories with auth requirements noted.
Vector Databases · AI for Developers
Open-source vector database written in Rust, with cloud offering.
Cheatsheets · Documentation & Learning
Clean, searchable cheat sheet collection for developers.
JSON · Data Formats
Generate types and serializers from JSON: TypeScript, Java, Kotlin, Go and more.
Queues & Streaming · Database
Reliable, widely-deployed message broker with AMQP.
Regex
Generate regular expressions from sample text matches.
Regex
Visualize regular expressions as railroad diagrams.
Regex
Online regex tester with reference, cheatsheet and community patterns.
Smart Contracts · Web3 & Blockchain
Browser IDE for Solidity — write, compile, deploy and debug contracts with zero local setup.
Tunneling & Debugging · API Tools
Open-source HTTP interception: modify requests, mock, and debug in browser.
Courses & Tutorials · Documentation & Learning
Community-driven developer roadmaps, guides and skill assessments.
Dependency Security · Security
Fast static analysis for finding bugs and vulnerabilities in code.
Hosting & Collaboration · Git & Version Control
The badge service for READMEs — build status, version, downloads and custom badges as compact SVGs.
APM & Tracing · Monitoring & Observability
Open-source Datadog alternative built on OpenTelemetry.
Compression & Optimization · Image & Media
Google's browser image compressor with advanced codecs (WebP, AVIF).
Markdown · PDF & Documents
Browser Markdown editor with Google Drive and GitHub sync.
NoSQL · Database
Multi-model database with records, graphs and documents (trending).
Compression & Optimization · Image & Media
Browser GUI for SVGO, optimizing SVG files with previews.
API Documentation · API Tools
OpenAPI tooling suite by SmartBear: UI, editor, codegen and more.