Open Source Projects using CSS
A curated collection of the 629 best open source software using CSS. Find the most popular and trending open source projects to learn from, contribute to, or use in your own projects.
Open source CI/CD platform that's faster and costs less
Stars
1,626Last commit
22 hours agoLicense
Unknown
Continuous integration and delivery platform offering faster builds, lower costs, and maintenance-free operations. Cut build times dramatically while reducing CI/CD expenses by 50%.
Open Source Alternative to:
Next-Gen ERD: Design, Explore, Document and Analyze your database.
Stars
2,192Last commit
2 months agoLicense
MIT
Azimutt is a powerful tool for seamlessly exploring, documenting, and optimizing large and complex databases.
Open Source Alternative to:
Encrypted, queryable backups for engineers who value time
Stars
2,092Last commit
13 hours agoLicense
ISC
Backup solution with CLI, API and UI interfaces. Clean defaults, easy deployment. Encrypted, queryable backups with deduplication and compression.
Open Source Alternative to:
Open-source message stream built on Postgres
Stars
2,214Last commit
8 months agoLicense
MIT
Sequin offers a feature-rich messaging system with a simple HTTP API, providing RabbitMQ-like functionality without adding complexity to your stack.
Open Source Alternative to:
Security framework that protects from within your product
Stars
1,549Last commit
14 days agoLicense
AGPL-3.0
Open-source security framework for threat detection, fraud prevention, and abuse monitoring. Self-hosted solution with built-in dashboard and risk scoring.
Open Source Alternative to:
Type 10x faster with AI-powered voice dictation
Stars
1,561Last commit
8 days agoLicense
MIT
Open source AI dictation app that transforms speech to text with context-aware formatting. Fast, accurate transcription for meetings, notes, and hands-free typing.
Open Source Alternative to:
AI code review that learns your team's standards
Stars
Stars growing over the last 30 days1,503Last commit
14 hours agoLicense
AGPL-3.0
Open source AI code reviewer that analyzes pull requests for quality, security, and performance while respecting your existing rules and model preferences.
Open Source Alternative to:
Transform any song into karaoke with AI-powered vocals
Stars
1,507Last commit
1 day agoLicense
GPL-3.0
AI-powered karaoke software that separates vocals from any song, transcribes lyrics with word-level sync, scores your pitch in real-time, and includes dynamic backgrounds.
Open Source Alternative to:
Managed identity and access management for any app
Stars
2,119Last commit
2 days agoLicense
Apache-2.0
Authgear is a managed IAM platform handling authentication, SSO, and user management for B2C and B2B apps, with biometrics, MFA, and zero-trust support.
Open Source Alternative to:
Privacy-first analytics for mobile and desktop apps
Stars
1,849Last commit
7 days agoLicense
AGPL-3.0
Open-source, self-hostable analytics platform for mobile and desktop apps, prioritizing user privacy and data control.
Open Source Alternative to:
Cloud-native framework for infrastructure from code
Stars
2,016Last commit
3 days agoLicense
Apache-2.0
Nitric automates cloud infrastructure provisioning from your application code for AWS, GCP and Azure
Open Source Alternative to:
Complete infrastructure monitoring with 25+ years of expertise
Stars
2,059Last commit
2 months agoLicense
GPL-2.0
Free open source IT monitoring solution for servers, networks, and applications. Trusted by 1M+ users worldwide with powerful alerting and enterprise-grade features.
Open Source Alternative to:
Self-hosted password vault built for teams and compliance
Stars
1,837Last commit
12 hours agoLicense
GPL-3.0
Collaborative password manager with folder-level access control, AES-256-GCM encryption, governance tools, and Linux password rotation, runs on your own servers.
Open Source Alternative to:
Simplify container deployment across environments
Stars
1,844Last commit
7 days agoLicense
Apache-2.0
Effortless container orchestration platform for seamless deployment, management, and monitoring of applications across multiple environments.
Open Source Alternative to:
Parallel AI agent workspaces with Git and project context
Stars
Stars growing over the last 30 days1,347Last commit
12 hours agoLicense
Apache-2.0
Run multiple AI coding agents in isolated Git worktrees, with cross-repo context, GitHub/Linear integrations, and support for Claude, Codex, Cursor, and more.
Open Source Alternative to:
Cross-system automation and knowledge base for accounting firms
Stars
1,722Last commit
5 months agoLicense
Unknown
Connects client data across tools, automates recurring accounting workflows, and maintains a self-updating knowledge base with human approval controls.
Privacy-first proof-of-work CAPTCHA without user friction
Stars
2,494Last commit
1 year agoLicense
AGPL-3.0
Privacy-focused proof-of-work CAPTCHA system that silently protects websites without tracking users or requiring image solving. Drop-in replacement for reCAPTCHA.
Open Source Alternative to:
Effortlessly split expenses with friends and groups
Stars
1,472Last commit
23 hours agoLicense
MIT
Free, open-source expense sharing app with multi-currency support, unequal splits, and receipt uploads. Import from Splitwise and enjoy PWA functionality.
Open Source Alternative to:
AI-powered PostgreSQL management made simple
Stars
1,452Last commit
12 hours agoLicense
AGPL-3.0
Modern PostgreSQL database management with AI-powered filtering, natural language queries, and cloud sync. Focus on your data while AI handles complexity.
Open Source Alternative to:
Unlock Data's Potential with Open Source Power
Stars
1,433Last commit
13 hours agoLicense
Apache-2.0
Leverage advanced analytics with a modern PostgreSQL kernel. 100% open source for robust data solutions.
Open Source Alternative to:
Local-first, offline-first no-code database platform
Stars
2,977Last commit
29 days agoLicense
AGPL-3.0
Build and manage custom databases with ease, create type-safe APIs, and develop applications quickly
Open Source Alternative to:
Privacy-first analytics without cookies or tracking
Stars
Stars growing over the last 30 days1,209Last commit
12 hours agoLicense
AGPL-3.0
Get powerful web analytics with zero cookies, 100% GDPR compliance, and full data ownership. Lightweight 3KB script delivers real-time insights without compromising user privacy.
Open Source Alternative to:
Secure self-hosted cloud storage with end-to-end encryption
Stars
Stars growing over the last 30 days1,533Last commit
1 day agoLicense
Unknown
Lightweight, self-hosted cloud storage built with Rust and Vue.js. Features end-to-end encryption, file sharing, search capabilities, and Docker deployment.
Open Source Alternative to:
Open-source personal finance management tool
Stars
2,954Last commit
22 days agoLicense
GPL-3.0
Self-hosted alternative to Mint and YNAB for budgeting and building wealth while maintaining full control of your financial data.
Open Source Alternative to:
Open-source knowledge management and collaboration platform
Stars
1,323Last commit
12 hours agoLicense
LGPL-2.1
XWiki is a flexible, feature-rich wiki software that helps organizations structure and share knowledge efficiently.
Open Source Alternative to:
AI chat companion with versatile model support
Stars
1,534Last commit
10 months agoLicense
Apache-2.0
Open-source chat application that lets you interact with multiple AI models in one interface, offering flexible conversations and diverse capabilities.
Open Source Alternative to:
Cookie-less analytics for privacy-focused insights
Stars
1,745Last commit
11 months agoLicense
Apache-2.0
Track user behavior, custom events, and conversion funnels in real-time with a single line of code, all while maintaining GDPR compliance.
Open Source Alternative to:
Lightroom-compatible RAW editor, no subscription
Stars
Stars growing quickly over the last 30 days1,229Last commit
11 hours agoLicense
MIT
Non-destructive RAW photo editor for macOS, Linux, and Windows that reads Lightroom catalogs, presets, and camera profiles. Free, MIT licensed, built in Rust.
Open Source Alternative to:
Powerful open-source business intelligence for data-driven decisions
Stars
1,026Last commit
13 hours agoLicense
AGPL-3.0
Connect multiple data sources, build complex queries, create insightful visualizations, and organize powerful dashboards to make informed business decisions.
Open Source Alternative to:
Unify APIs, databases, and services effortlessly
Stars
1,279Last commit
11 hours agoLicense
Apache-2.0
A powerful backend framework that simplifies API integration, enhances security, and boosts developer productivity for modern web applications.
Open Source Alternative to:
GitOps orchestration for infrastructure as code
Stars
1,308Last commit
22 hours agoLicense
MPL-2.0
Automate infrastructure changes with secure GitOps workflows. Plan, validate, and deploy Terraform, OpenTofu, and Pulumi directly from pull requests.
Open Source Alternative to:
Fast, scalable analytics infrastructure
Stars
1,665Last commit
7 months agoLicense
MIT
Open source analytics platform built on ClickHouse and Kafka, offering high-speed event tracking and real-time querying capabilities.
Open Source Alternative to:
Transform team email into efficient collaborative workflows
Stars
1,760Last commit
8 months agoLicense
AGPL-3.0
Streamline team communication with shared inboxes, unlimited email addresses, and customizable workflows. Perfect for modern businesses seeking organized email management.
Open Source Alternative to:
Transform your source code into stunning visuals
Stars
1,846Last commit
10 months agoLicense
MIT
Create beautiful, customizable images of your source code with ease, perfect for presentations, documentation, and social media sharing.
Self-hosted AI agents and workflows across any channel
Stars
Stars declining over the last 30 days1,154Last commit
27 days agoLicense
AGPL-3.0
Build and run AI agents, agentic workflows, and multichannel automation on your own infrastructure, with memory, RAG, MCP tools, and full data control.
Open Source Alternative to:
Open-source webhooks for seamless integrations
Stars
1,499Last commit
1 day agoLicense
SSPL-1.0
Self-hosted webhook solution for effortless event-driven communication between applications, enhancing system interoperability and automation.
Open Source Alternative to:
Self-hostable omnichannel chatbot platform for agencies
Stars
Stars growing quickly over the last 30 days980Last commit
11 hours agoLicense
MIT
Open source agentic chat marketing platform you can self-host, white-label, and resell. Automate omnichannel conversations across WhatsApp, Messenger, Instagram, Telegram, Zalo, TikTok, Email, and Webchat with a flow builder, shared inbox, AI agents, CRM, and broadcasts.
Open Source Alternative to:
Local-first notes app with no cloud, no AI, no tracking
Stars
1,348Last commit
3 days agoLicense
MIT
A privacy-focused, offline-first note-taking app that stores everything on your device, with Markdown, note linking, file attachments, LaTeX math, and bring-your-own sync.
Open Source Alternative to:
Flexible billing infrastructure for modern SaaS
Stars
Stars growing over the last 30 days1,337Last commit
11 days agoLicense
AGPL-3.0
Open-source pricing and billing platform that helps SaaS companies launch, test, and scale complex billing models with ease. Features metering, invoicing, and real-time data.
Open Source Alternative to:
Self-hosted uptime monitoring you own and control
Stars
1,198Last commit
11 hours agoLicense
MIT
Open-source uptime monitoring solution with real-time alerts, status pages, and comprehensive checks for websites, APIs, databases, and services.
Open Source Alternative to:
Clean, distraction-free note-taking with local storage
Stars
1,187Last commit
4 days agoLicense
AGPL-3.0
Minimal note-taking app storing Markdown notes in local SQLite database. Features instant search, flexible tagging, keyboard shortcuts, and offline access.
Open Source Alternative to:
Create, sell, and manage online courses with ease
Stars
1,279Last commit
12 days agoLicense
AGPL-3.0
An open-source platform for building and selling online courses, featuring customizable themes, integrated payments, and user management.
Open Source Alternative to:
Stellar Hosted – Managed Open Source software hosting in the EU: secure, compliant, fast.
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