Freemium
HashiCorp Vault
Open SourcePasswords & IDs · Security
Manage secrets, certificates and encryption centrally.
secretsmanagementhashicorp
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Passwords & IDs · Security
Manage secrets, certificates and encryption centrally.
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.
NoSQL · Database
Purpose-built time-series database for metrics and events.
APM & Tracing · Monitoring & Observability
Open-source distributed tracing platform, CNCF graduated.
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
Beautiful, shareable JSON viewer with previews for many data types.
Notebooks & Data Science · Data & Analytics
The standard interactive notebooks for data science and ML.
Web Servers & Proxies · DevOps
Popular open-source API gateway and microservices management.
Agent & LLM Frameworks · AI for Developers
Open-source LLM observability: traces, evals and prompt management.
Generators · CSS Tools
Interactive CSS Grid layout builder with code export.
Cheatsheets & Learning · Git & Version Control
Interactive visualization game for learning Git branching.
SSL & TLS · Security
Diagnose why Let's Encrypt certificate issuance fails for a domain.
Models & LLM APIs · AI for Developers
Open-source, multi-provider chat UI with agents and artifacts.
Models & LLM APIs · AI for Developers
Open-source LLM gateway: one API for 100+ providers.
Models & LLM APIs · AI for Developers
Open-source AI chat framework with plugins and agent marketplace.
Authentication · API Tools
Open-source auth infrastructure with a beautiful admin console — OIDC/OAuth, SSO and user management, self-hostable.
Logs & Metrics · Monitoring & Observability
Horizontally-scalable log aggregation designed like Prometheus.
Relational · Database
Community-developed MySQL fork with a permissive license.