Open Source Projects using CSS
A curated collection of the 580 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.
Dashboard for running multiple coding agents in parallel
Stars
5,456Last commit
15 hours agoLicense
Apache-2.0
Desktop app that runs 25+ coding agents simultaneously, each isolated in its own Git worktree, so you can orchestrate code changes without switching tools.
Open Source Alternative to:
Open-source cloud communications platform for developers
Stars
8,079Last commit
2 days agoLicense
MIT
Build and deploy powerful voice and messaging applications with ease using Fonoster's flexible, scalable, and developer-friendly platform.
Open Source Alternative to:
Secure collaboration with end-to-end encryption
Stars
7,853Last commit
20 hours agoLicense
AGPL-3.0
Open-source collaboration suite offering encrypted document editing, file sharing, and team workspaces with complete privacy protection.
Open Source Alternative to:
Self-hosted file sharing built for digital sovereignty
Stars
5,834Last commit
12 hours agoLicense
Apache-2.0
Self-hostable cloud file management and collaboration platform with an integrated office suite, zero-trust security, and GDPR compliance for teams and organizations.
Open Source Alternative to:
Launch Your Store in Minutes, No Code Needed
Stars
5,479Last commit
14 hours agoLicense
MIT
Fast, modern e-commerce with instant setup and full customization. Powered by Stripe for seamless transactions.
Open Source Alternative to:
Ad-free photo sharing with privacy and federation
Stars
7,069Last commit
18 hours agoLicense
AGPL-3.0
Decentralized photo sharing platform with chronological feeds, privacy controls, and ActivityPub federation. No ads, no algorithms, just authentic connections.
Open Source Alternative to:
Build reliable AI apps with comprehensive observability
Stars
6,088Last commit
4 days agoLicense
Apache-2.0
Open-source platform for logging, monitoring, and debugging LLM applications. Route, debug, and analyze AI apps with comprehensive observability tools.
Open Source Alternative to:
Transform SQL into beautiful data stories
Stars
6,866Last commit
1 day agoLicense
MIT
Create data-driven websites and reports using SQL and Markdown, with automatic visualizations and interactive elements.
Open Source Alternative to:
Open-source legal AI that law firms control and extend
Stars
4,140Last commit
12 hours agoLicense
AGPL-3.0
Self-hostable alternative to Harvey and Legora with document analysis, contract drafting, tabular review, and reusable workflows. Zero licensing costs, full data control.
Open Source Alternative to:
Build stateful backends with in-memory actors
Stars
6,071Last commit
22 hours agoLicense
Apache-2.0
Open-source infrastructure for long-lived, in-memory processes called Actors. Combines state and compute with sub-millisecond latency, realtime capabilities, and horizontal scaling.
Open Source Alternative to:
Automated translations that scale with your code and commits
Stars
5,405Last commit
11 hours agoLicense
Apache-2.0
Transform your app into a global product with AI-powered localization that integrates directly into your development workflow. Supports 83+ languages with Git-native automation.
Open Source Alternative to:
Self-hosted cloud platform with automated security
Stars
6,123Last commit
21 hours agoLicense
Unknown
Complete self-hosting solution with automated maintenance, Smart-Shield protection, anti-DDoS, SSO authentication, and VPN access for secure private cloud management.
Open Source Alternative to:
Intercept, modify, and debug HTTP(S) requests effortlessly
Stars
6,751Last commit
18 hours agoLicense
AGPL-3.0
A powerful browser extension and desktop app for developers to manipulate network requests, debug APIs, and improve web app testing
Open Source Alternative to:
Virtual office platform for engaging remote collaboration
Stars
5,722Last commit
13 hours agoLicense
Unknown
Create customizable virtual workspaces for remote teams to interact naturally, host events, and collaborate through spontaneous conversations and scheduled meetings.
Open Source Alternative to:
Open-source BI for modern data teams
Stars
6,062Last commit
11 hours agoLicense
MIT
Self-serve analytics platform that transforms dbt models into interactive dashboards, enabling data-driven decisions across organizations.
Open Source Alternative to:
Organize and secure your documents in one central hub
Stars
5,222Last commit
1 day agoLicense
AGPL-3.0
A document management platform that helps you archive, organize, and search files with email ingestion, tagging capabilities, and powerful search functionality.
Open Source Alternative to:
Smart desktop AI assistant with powerful local knowledge features
Stars
5,340Last commit
1 month agoLicense
Unknown
Cross-platform desktop AI assistant supporting multiple providers, local knowledge base, and custom prompts. Integrates MCP protocol for enhanced AI tool capabilities.
Open Source Alternative to:
Open source kanban boards with unlimited everything
Stars
5,381Last commit
8 days agoLicense
AGPL-3.0
Free kanban project management with unlimited boards, lists, and cards. Import Trello boards, collaborate with teams, and self-host for complete control.
Open Source Alternative to:
Feature flags and remote config for rapid deployment
Stars
6,524Last commit
11 hours agoLicense
BSD-3-Clause
Powerful feature management platform for seamless software releases, A/B testing, and personalized user experiences.
Open Source Alternative to:
The open-source, affordable email platform
Stars
5,379Last commit
3 days agoLicense
AGPL-3.0
Plunk unifies marketing, transactional, and broadcast emails into a single, complete solution for businesses of all sizes.
Open Source Alternative to:
Secure, scalable API key management for developers
Stars
5,421Last commit
12 hours agoLicense
AGPL-3.0
Streamline API authentication with UnKey's powerful, developer-friendly platform for creating, revoking, and monitoring API keys.
Open Source Alternative to:
Distributed OLAP database for real-time analytics at scale
Stars
6,122Last commit
13 hours agoLicense
Apache-2.0
Sub-second SQL queries on fresh streaming data at petabyte scale, built for high-concurrency user-facing apps and AI agent backends.
Open Source Alternative to:
Secure, encrypted notes for your digital life
Stars
6,594Last commit
2 days agoLicense
AGPL-3.0
Cross-platform note-taking app with end-to-end encryption, offline access, and powerful organization features for privacy-conscious users.
Open Source Alternative to:
Self-hosted group chat without recurring subscription fees
Stars
4,498Last commit
19 hours agoLicense
MIT
Install your own group chat system with @mentions, DMs, and mobile support. One-time purchase, no monthly fees. Includes full source code for customization.
Open Source Alternative to:
Continuous web-based localization for global reach
Stars
6,031Last commit
13 hours agoLicense
GPL-3.0
Web-based continuous localization platform with version control integration, quality checks, and clean interface. Used by 2,500+ projects in 165+ countries.
Open Source Alternative to:
Desktop SQL client with built-in MCP for AI agent access
Stars
4,154Last commit
1 day agoLicense
Apache-2.0
Desktop database client for PostgreSQL, MySQL/MariaDB, SQLite, and 14+ more databases, with a built-in MCP server, SQL notebooks, visual query builder, and a plugin system.
Open Source Alternative to:
Deploy a professional status page in minutes, no coding required
Stars
5,119Last commit
14 hours agoLicense
MIT
Free, open-source status page and uptime monitor with Docker deployment. Track 11 service types, manage incidents, schedule maintenance, and notify subscribers instantly.
Open Source Alternative to:
Clean your system and free disk space
Stars
6,646Last commit
14 hours agoLicense
GPL-3.0
BleachBit frees disk space & protects privacy by deleting cache, cookies, history & temp files from Firefox, Chrome & more. Open source for Linux/Windows.
Open Source Alternative to:
Professional image editing without the price tag
Stars
6,369Last commit
11 hours agoLicense
Unknown
Free, open-source image editor with professional tools for photo manipulation, digital art creation, and graphic design. Cross-platform support.
Open Source Alternative to:
Effortless event-driven workflows for modern applications
Stars
5,748Last commit
12 hours agoLicense
SSPL-1.0
Simplify backend processes with event-driven functions, seamless integrations, and powerful debugging tools for developers.
Open Source Alternative to:
Free, cross-platform video editor that's easy to learn
Stars
6,182Last commit
3 days agoLicense
GPL-3.0
A free, open-source video editor for Linux, Mac, and Windows with animation, effects, multi-track editing, and 3D title rendering.
Open Source Alternative to:
Secure password management for teams
Stars
6,082Last commit
13 hours agoLicense
AGPL-3.0
Open source password manager focused on security, collaboration and privacy for organizations
Open Source Alternative to:
Build reliable AI agents with unified tool integration
Stars
4,881Last commit
3 months agoLicense
Apache-2.0
Platform for connecting AI agents to 500+ tools with built-in multi-tenant auth management and granular permissions using either function calling or a unified MCP server
Open Source Alternative to:
Full observability for AI agents in production
Stars
4,596Last commit
20 hours agoLicense
MIT
Open-source platform for monitoring AI agents: captures traces, surfaces failure patterns, alerts on issues, and helps you verify fixes with automated evals.
Open Source Alternative to:
Flexible eCommerce platform for brands that stand out
Stars
5,321Last commit
1 day agoLicense
Unknown
Open-source eCommerce platform offering customization, scalability and enterprise-grade features for brands of all sizes
Open Source Alternative to:
Pay per email sent, not for contact storage
Stars
4,617Last commit
27 days agoLicense
AGPL-3.0
Open source email platform for transactional and marketing emails. Self-host or use cloud service with transparent pricing - pay only for emails sent.
Open Source Alternative to:
Powerful helpdesk solution for streamlined customer service
Stars
5,859Last commit
16 hours agoLicense
AGPL-3.0
Zammad is an open-source helpdesk software that centralizes customer communications and helps deliver great service experiences efficiently.
Open Source Alternative to:
Build reliable LLM apps with integrated workflows
Stars
4,501Last commit
11 hours agoLicense
MIT
Open-source LLMOps platform providing prompt management, evaluation, and observability tools for building robust AI applications with team collaboration.
Open Source Alternative to:
Spreadsheet-like interface for PostgreSQL databases
Stars
5,099Last commit
1 day agoLicense
GPL-3.0
A self-hosted tool that provides an intuitive, spreadsheet-style interface for viewing, editing, and querying PostgreSQL databases without technical expertise.
Open Source Alternative to:
Navigate anywhere with detailed offline maps and GPS
Stars
5,919Last commit
12 hours agoLicense
Unknown
Comprehensive offline navigation app with detailed maps, turn-by-turn guidance, and specialized routing for hiking, cycling, and walking worldwide.
Open Source Alternative to:
Open-source CRM that puts simplicity and control first
Stars
3,359Last commit
2 days agoLicense
AGPL-3.0
A flexible and customizable CRM platform for managing contacts, deals, and customer relationships without the complexity or user-based pricing of traditional solutions.
Open Source Alternative to:
Enterprise workplace AI with data you own and control
Stars
3,655Last commit
18 hours agoLicense
Apache-2.0
Self-hostable enterprise AI platform that unifies business data across apps, powers a knowledge graph for cited answers, and lets teams build AI agents across their stack.
Open Source Alternative to:
CodeRabbit – The leading AI Code Review platform. Ship better quality code in 50% less time, with 90% fewer bugs.
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