Free
Ecosystem · CSS Tools
Official Tailwind CSS playground for trying classes in the browser.
tailwindplaygroundcss
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Ecosystem · CSS Tools
Official Tailwind CSS playground for trying classes in the browser.
Containers · DevOps
Free in-browser Docker playground for experiments.
Serverless & BaaS · Database
Open-source backend in one file: SQLite database, auth, realtime and files.
Payments · API Tools
Open-source payments and monetization for developers — checkouts, subscriptions and license keys, MoR model.
Stock & Placeholders · Image & Media
Thousands of free low-poly 3D models (CC0/CC-BY) with a searchable gallery and a Google-Drive-like library.
Containers · DevOps
Self-hosted GUI for managing Docker and Kubernetes environments.
Penetration Testing · Security
Free, in-depth web security training with interactive labs, maintained by the Burp Suite team.
Design Systems · Design & Prototyping
GitHub's design system with React components and tokens.
Cheatsheets & Learning · Git & Version Control
The official, free Pro Git book covering Git in depth.
Courses & Tutorials · Documentation & Learning
Kelas online Eko Kurniawan — tutorial backend, Java, Go dan arsitektur berbahasa Indonesia dari dasar sampai mahir.
Practice & Challenges · Documentation & Learning
Mathematical and computational programming problems.
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.
Other Formats · Data Formats
Official Protocol Buffers documentation from Google.
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.
QR & Barcode · Encoding & Decoding
Free QR code generator with custom colors, shapes and logos.
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.
Models & LLM APIs · AI for Developers
Alibaba's open-weight model family with multilingual strengths.
Queues & Streaming · Database
Reliable, widely-deployed message broker with AMQP.
PaaS & Edge · Cloud Platforms
Deploy services and databases quickly with sensible defaults.
Text & Diff · Developer Utilities
Beautiful code screenshots with themes and gradients by Raycast.
Documentation Generators · PDF & Documents
Hosted documentation platform for Sphinx and MkDocs projects.