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 workflow automation for developers
Stars
18,229Last commit
7 hours agoLicense
Unknown
Powerful, self-hosted platform for building and running workflows, scripts, and apps with code-first approach and collaborative features.
Open Source Alternative to:
Create, edit and share documents with real-time collaboration
Stars
16,934Last commit
7 hours agoLicense
MIT
Transform document collaboration with real-time editing, version control, and secure sharing features that enhance team productivity and communication.
Open Source Alternative to:
Scalable open-source distributed storage system
Stars
17,140Last commit
17 hours agoLicense
Unknown
Ceph provides unified object, block, and file storage from a single cluster built on commodity hardware.
Open Source Alternative to:
Secure password management for individuals and businesses
Stars
20,422Last commit
9 hours agoLicense
AGPL-3.0
Bitwarden is an open source password manager that securely stores, shares, and autofills passwords across unlimited devices.
Open Source Alternative to:
Run long-running AI tasks without timeouts or servers
Stars
16,584Last commit
7 hours agoLicense
Apache-2.0
Open source TypeScript platform for building and deploying AI agents and background workflows with retries, queues, observability, and elastic scaling.
Open Source Alternative to:
Fast, secure cloud development environments on your infrastructure
Stars
Stars growing over the last 30 days17,112Last commit
8 hours agoLicense
AGPL-3.0
Self-hosted development platform that enables secure, scalable remote coding with automated provisioning, reduced cloud costs, and enterprise-grade security.
Open Source Alternative to:
Open-source mail server with unlimited sending & AI tools
Stars
15,931Last commit
4 months agoLicense
AGPL-3.0
Self-hosted email marketing platform with unlimited sending, AI-powered email creation, real-time analytics, and no monthly fees. Complete SMTP solution.
Open Source Alternative to:
Professional audio editing made simple and free
Stars
18,787Last commit
1 day agoLicense
Unknown
Free, open-source audio editor and recorder for all platforms. Record, edit, mix and enhance audio with professional tools. Perfect for music, podcasts, and more.
Open Source Alternative to:
AI agent runtime with encrypted enclaves for your secrets
Stars
12,668Last commit
17 hours agoLicense
Apache-2.0
Runs AI agents inside Trusted Execution Environments on NEAR AI Cloud, keeping credentials encrypted and invisible to the model at all times.
Open Source Alternative to:
Ad-free music player that streams from multiple sources
Stars
18,745Last commit
1 day agoLicense
AGPL-3.0
Open-source desktop music player for Windows, macOS, and Linux. Search artists and tracks across multiple sources, build playlists, and listen without ads or tracking.
Open Source Alternative to:
Open-source API documentation and testing platform
Stars
16,291Last commit
9 hours agoLicense
MIT
Scalar is an open-source tool for building, customizing, and hosting interactive API documentation with OpenAPI support.
Open Source Alternative to:
SQLite-compatible database for scalable multi-tenant applications
Stars
17,278Last commit
3 days agoLicense
MIT
Turso provides a simple developer experience with SQLite compatibility, allowing you to build and scale multi-tenant applications with unlimited databases.
Open Source Alternative to:
Open source headless commerce with REST API, no platform fees, built for B2B and marketplaces
Stars
15,763Last commit
7 hours agoLicense
BSD-3-Clause
Headless eCommerce platform with REST API, TypeScript SDK, and Next.js storefront. Handle B2B, multi-vendor marketplaces, and cross-border commerce. Self-hosted, open source, zero fees.
Open Source Alternative to:
Open-source ecommerce platform for WordPress
Stars
10,559Last commit
7 hours agoLicense
GPL-2.0
Build and manage online stores with customizable features, extensions, and themes for businesses of all sizes.
Open Source Alternative to:
Understand your audience with privacy-first analytics.
Stars
13,136Last commit
1 day agoLicense
AGPL-3.0
Get next-gen, open-source, and cookieless web analytics. Understand user behavior with session replays, real-time data, and web vitals. GDPR/CCPA compliant.
Open Source Alternative to:
Open-source Q&A platform for knowledge sharing
Stars
15,701Last commit
5 days agoLicense
Apache-2.0
A versatile, community-driven Q&A platform that fosters collaboration and knowledge exchange within organizations and communities.
Open Source Alternative to:
Classic, agile, or hybrid project management, self-hosted
Stars
16,494Last commit
7 hours agoLicense
GPL-3.0
Full-featured project management platform with Gantt charts, agile boards, time tracking, and team collaboration. Self-host or use managed cloud hosting.
Open Source Alternative to:
Privacy-first survey and experience management platform
Stars
13,127Last commit
7 hours agoLicense
AGPL-3.0
Collect feedback across websites, apps, and emails with targeted surveys, user segmentation, and GDPR-compliant data handling. Self-host or use the cloud.
Open Source Alternative to:
Secure, customizable identity infrastructure for developers
Stars
15,353Last commit
1 day agoLicense
AGPL-3.0
ZITADEL provides a comprehensive identity management solution with easy APIs, customizable workflows, and serverless deployment options.
Open Source Alternative to:
Privacy-first offline maps for hiking, cycling & navigation
Stars
15,714Last commit
11 hours agoLicense
Apache-2.0
Free, open-source offline maps app with detailed trails, turn-by-turn navigation, and zero tracking. Perfect for hikers, cyclists, and travelers seeking privacy.
Open Source Alternative to:
Secure cloud environments for enterprise AI agents
Stars
Stars growing over the last 30 days14,458Last commit
19 hours agoLicense
Apache-2.0
Provide AI agents with secure, isolated sandboxes featuring real-world tools, code execution, and enterprise-grade security. Trusted by 88% of Fortune 100 companies.
Open Source Alternative to:
Visual database for workflow automation across apps
Stars
15,639Last commit
1 month agoLicense
AGPL-3.0
AITable.ai offers a visual database platform that simplifies workflow automation and connects to over 6,000 apps through integrations like Zapier and Make.
Open Source Alternative to:
Common layer for composing and governing AI agents
Stars
Stars growing over the last 30 days10,914Last commit
7 hours agoLicense
Apache-2.0
Meta-harness that sits above Claude Code, Codex, and other AI agents to add policy enforcement, sandboxing, and real-time collaborative sessions.
Open Source Alternative to:
Secure, seamless authentication for modern applications
Stars
14,728Last commit
7 hours agoLicense
MPL-2.0
An open-source identity solution offering customizable login experiences, multi-tenant support, and comprehensive user management.
Open Source Alternative to:
Advanced terminal with modern features for Mac developers
Stars
18,200Last commit
7 hours agoLicense
GPL-2.0
Feature-rich terminal replacement for macOS with split panes, search, autocomplete, and extensive customization options for enhanced productivity.
Open Source Alternative to:
Streamline your business finances and operations
Stars
15,086Last commit
4 months agoLicense
AGPL-3.0
All-in-one tool for freelancers and small businesses to manage finances, track time, store files, and send invoices efficiently.
Open Source Alternative to:
Zero-knowledge encrypted notes that sync across all devices
Stars
14,802Last commit
7 hours agoLicense
GPL-3.0
End-to-end encrypted note-taking app with zero-knowledge architecture, cross-device sync, web clipper, and a self-hostable sync server.
Open Source Alternative to:
Secure, customizable authentication for your applications
Stars
15,349Last commit
8 hours agoLicense
Unknown
Open-source authentication solution offering flexible, self-hosted user management with advanced features and easy integration.
Open Source Alternative to:
Secure and streamline database changes with CI/CD automation
Stars
14,616Last commit
7 hours agoLicense
MIT
Comprehensive platform for database schema migrations, security controls, and data masking with built-in review workflows and GitOps integration.
Client-side encryption for your cloud files
Stars
16,334Last commit
4 days agoLicense
GPL-3.0
Encrypts files and filenames locally before they reach Dropbox, Google Drive, OneDrive, or any other cloud, so only you hold the key.
Open Source Alternative to:
Ultra-fast data transformation for AI with lineage
Stars
11,725Last commit
9 hours agoLicense
Apache-2.0
Open-source ETL framework built in Rust for AI workloads. Features incremental processing, data lineage, and observability tools for semantic search and RAG applications.
Open Source Alternative to:
Build full-stack apps with TypeScript and real-time sync
Stars
12,727Last commit
4 days agoLicense
Unknown
Open-source reactive database that keeps your web and mobile apps in sync. Write everything in TypeScript with built-in auth, cron jobs, and AI integration.
Open Source Alternative to:
Real-time analytics database for sub-second OLAP queries
Stars
14,089Last commit
11 hours agoLicense
Apache-2.0
Columnar, time-indexed analytics database built for streaming and batch data at scale, handling billions to trillions of rows with millisecond query response times.
Open Source Alternative to:
Centralize, transform, and stash your data
Stars
14,966Last commit
11 hours agoLicense
Unknown
Logstash is a free and open server-side data processing pipeline that ingests data from multiple sources, transforms it, and sends it to your desired destination.
Open Source Alternative to:
Build beautiful documentation sites with Next.js
Stars
13,421Last commit
9 hours agoLicense
MIT
A flexible Next.js framework for creating stunning documentation sites with MDX support, built-in search, and customizable components.
Open Source Alternative to:
Open source messaging with privacy and community focus
Stars
10,620Last commit
1 day agoLicense
AGPL-3.0
Free, open-source instant messaging and VoIP platform with full Markdown support, voice/video calls, moderation tools, and self-hosting options for communities.
Open Source Alternative to:
Create powerful chatbots without coding
Stars
10,561Last commit
1 day agoLicense
Unknown
Design, build, and deploy interactive chatbots with a visual editor. Integrate easily and collect data effortlessly.
Open Source Alternative to:
Minimalistic AI-powered search engine for instant answers
Stars
11,902Last commit
2 months agoLicense
AGPL-3.0
Scira delivers concise, AI-generated responses to queries using a clean interface and powerful search capabilities.
Open Source Alternative to:
Unify, automate, and elevate your monitoring workflow
Stars
12,421Last commit
22 days agoLicense
MIT
Open-source platform for centralizing alerts, automating responses, and enhancing incident management across your tech stack.
Open Source Alternative to:
Your all-in-one marketplace for digital creators and products
Stars
9,987Last commit
7 hours agoLicense
MIT
A digital marketplace platform where creators can sell digital products, from courses to software, with built-in payment processing and content delivery.
Open Source Alternative to:
Complete production stack for AI teams
Stars
13,228Last commit
5 months agoLicense
MIT
Comprehensive AI platform with gateway, observability, guardrails, and prompt management. Access 1,600+ LLMs via unified API with enterprise-grade security.
Open Source Alternative to:
Unified file management for your enterprise storage
Stars
14,814Last commit
4 days agoLicense
AGPL-3.0
Filestash is an open-source file manager that integrates with multiple storage backends, authentication systems, and offers customization options.
Open Source Alternative to:
Sent – Messaging Infrastructure for Developers. One API for SMS, WhatsApp, and RCS across 190+ countries.
Sent
Openlane
Bright Data