Free
Passwords & IDs · Security
Online GUID/UUID generator with many formatting options.
uuidguidgenerator
Browse the complete directory — use filters to narrow down.
Passwords & IDs · Security
Online GUID/UUID generator with many formatting options.
Communities · Documentation & Learning
Y Combinator's tech news and discussion community.
Color Tools
Curated palettes shown in context on a real website.
Passwords & IDs · Security
Manage secrets, certificates and encryption centrally.
Communities · Documentation & Learning
Blogging platform for developers with custom domains.
Passwords & IDs · Security
Check if your email or password has appeared in known data breaches.
Agent & LLM Frameworks · AI for Developers
Open-source LLM observability — logging, caching, rate limiting and cost tracking behind a one-line proxy.
API Clients · API Tools
Lightweight, open-source API development ecosystem in the browser.
Headers & CSP · Security
Mozilla's scanner that grades a site's security headers and config.
API Mocking · API Tools
HTTP request and response service for testing clients.
Models & LLM APIs · AI for Developers
The AI community hub: models, datasets, spaces and libraries.
Illustrations & Assets · Design & Prototyping
Free modular people illustrations by Pablo Stanley — rotate limbs and mix outfits in a friendly flat style.
Design Systems · Design & Prototyping
Apple's design guidelines for iOS, macOS and other platforms.
Regex
Collection of ready-made regex snippets with visual explanations.
NoSQL · Database
Purpose-built time-series database for metrics and events.
APM & Tracing · Monitoring & Observability
Open-source distributed tracing platform, CNCF graduated.
Minifiers · Developer Utilities
Free online JavaScript minifier with API access.
References · Documentation & Learning
The Modern JavaScript Tutorial — the deepest free JS reference from basics to advanced browser APIs.
CI/CD · DevOps
The classic open-source automation server for CI/CD.
JSON · Data Formats
Open-source JSON visualizer that turns data into interactive graphs.
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.