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.
Modern payment infrastructure for digital products and SaaS
Stars
10,203Last commit
12 hours agoLicense
Apache-2.0
Comprehensive payment solution with built-in tax handling, automated benefits, and seamless integrations for digital product and SaaS businesses.
Open Source Alternative to:
Free online accounting for small businesses and freelancers
Stars
10,078Last commit
2 days agoLicense
Unknown
Self-hostable accounting software covering invoicing, expense tracking, cash flow, and client portals. Free to use, available in 50+ languages.
Open Source Alternative to:
Open source marketing automation for everyone
Stars
10,371Last commit
14 hours agoLicense
Unknown
Mautic is a free and open source marketing automation platform that helps businesses manage leads, create campaigns, and analyze results.
Open Source Alternative to:
Full-stack observability without the enterprise price tag
Stars
9,846Last commit
11 hours agoLicense
MIT
Open source observability platform unifying session replays, logs, traces, metrics and errors. Fast search, automatic clustering, $0.40/GB pricing.
Open Source Alternative to:
Open-source document sharing with powerful analytics
Stars
8,960Last commit
2 days agoLicense
AGPL-3.0
Secure, customizable platform for sharing documents and tracking engagement. Perfect for sales teams, marketers, and businesses.
Open Source Alternative to:
Simple, secure project management for development teams
Stars
8,396Last commit
1 day agoLicense
MIT
Self-hosted project management platform with visual task management, data privacy, and complete control over customization - built by developers for developers.
Open Source Alternative to:
Design editor that opens Figma files, runs AI, and stays local
Stars
7,894Last commit
12 hours agoLicense
MIT
A Figma-compatible design editor with built-in AI chat, headless CLI, real-time P2P collaboration, and a Vue SDK for building custom editors. No account needed.
Open Source Alternative to:
Goal-driven project management for all brains
Stars
11,400Last commit
6 days agoLicense
AGPL-3.0
Open-source software designed to streamline tasks, boost productivity, and enhance collaboration for teams of all types, including those with ADHD and neurodiversity.
Open Source Alternative to:
Effortless time tracking for open source projects
Stars
8,864Last commit
13 hours agoLicense
AGPL-3.0
Seamlessly track time across multiple projects, generate insightful reports, and optimize your open source contributions.
Open Source Alternative to:
Full-text & vector search at the edge.
Stars
10,523Last commit
17 days agoLicense
Unknown
Blend full-text and semantic search for unlimited queries across 300 global locations. Get precise answers and matches at a flat rate, no matter your search volume.
Open Source Alternative to:
Send invoices, accept payments, manage your business—all free
Stars
10,012Last commit
1 day agoLicense
Elastic-2.0
Free invoicing software for freelancers and small businesses. Create professional invoices, track expenses, accept online payments, and manage projects without hidden fees.
Open Source Alternative to:
Self-hosted bookmark manager built for speed and simplicity
Stars
11,081Last commit
2 days agoLicense
MIT
Minimal, fast bookmark manager with automatic metadata fetching, archiving, multi-user support, and browser extensions. Easy Docker setup with SQLite.
Open Source Alternative to:
Terminal-native AI coding agent built on ZSH
Stars
7,498Last commit
13 hours agoLicense
Apache-2.0
AI coding harness that runs inside your terminal, mixes LLMs per task, and uses multi-agent architecture to handle large codebases without bloating context.
Open Source Alternative to:
Visual web development with code-level control
Stars
8,848Last commit
17 hours agoLicense
AGPL-3.0
Powerful no-code platform for building responsive websites. Combines visual editing with full HTML/CSS customization.
Open Source Alternative to:
Secure desktop investment tracker for private wealth management
Stars
8,676Last commit
12 hours agoLicense
AGPL-3.0
Wealthfolio is a simple, secure desktop app for tracking investments and managing your wealth without compromising data privacy.
Open Source Alternative to:
Modern kanban that's fast, fun, and refreshingly simple
Stars
8,099Last commit
12 hours agoLicense
Unknown
Track issues, ideas, and projects with a modern kanban board that's fast and straightforward. Free for 1000 cards, then $20/month for unlimited use.
Open Source Alternative to:
Status page and uptime monitoring for growing teams
Stars
8,995Last commit
16 hours agoLicense
AGPL-3.0
Open-source status page and uptime monitor that tracks endpoints from 28 global regions, communicates incidents, and helps satisfy SOC 2 audit requirements.
Open Source Alternative to:
Track, analyze, and optimize your investments effortlessly
Stars
9,161Last commit
11 hours agoLicense
AGPL-3.0
Open-source wealth management software for tracking stocks, ETFs, and cryptocurrencies across multiple portfolios
Open Source Alternative to:
Ultra-fast AI gateway with enterprise-grade reliability
Stars
7,461Last commit
11 hours agoLicense
Apache-2.0
Open-source AI gateway delivering 50x faster performance than alternatives. Access 1000+ models from 8+ providers with built-in governance, fallback, and observability.
Open Source Alternative to:
Flexible, scalable Node.js CMS and app framework
Stars
9,960Last commit
1 day agoLicense
MIT
A powerful, customizable content management system and application framework built on Node.js, GraphQL, and React
Open Source Alternative to:
Control browser fleets in the cloud for AI automation
Stars
7,514Last commit
1 day agoLicense
Apache-2.0
Open-source browser API designed for AI agents. Run headless browsers with built-in CAPTCHA solving, proxy support, and session management. Quick setup in under 1s.
Open Source Alternative to:
Magical data pipeline tool for seamless transformations
Stars
8,806Last commit
7 days agoLicense
Apache-2.0
Open-source data pipeline platform for effortless data integration, transformation, and orchestration using Python, SQL, and R.
Open Source Alternative to:
Serverless backend platform for modern app development
Stars
9,280Last commit
13 hours agoLicense
MIT
Fully managed backend infrastructure with built-in authentication, database, storage, and serverless functions for rapid application development.
Open Source Alternative to:
Effortless CI/CD for modern cloud applications
Stars
7,763Last commit
11 hours agoLicense
MIT
Durable orchestration platform for managing AI agents, scheduling background tasks, and running mission-critical workflows.
Open Source Alternative to:
Privacy-first CAPTCHA alternative with proof-of-work
Stars
7,553Last commit
6 days agoLicense
Apache-2.0
Lightweight open-source CAPTCHA solution using SHA-256 proof-of-work. 250x smaller than hCaptcha, fully customizable, and privacy-focused with zero telemetry.
Open Source Alternative to:
Real-time observability for modern web applications
Stars
9,366Last commit
1 day agoLicense
Apache-2.0
Comprehensive monitoring solution offering error tracking, session replay, and performance insights for seamless debugging and optimization.
Open Source Alternative to:
Flexible e-commerce for modern businesses
Stars
8,356Last commit
18 hours agoLicense
MIT
A headless, API-first e-commerce framework built on Node.js with TypeScript, offering customization and scalability for online stores.
Open Source Alternative to:
Visual development platform for modern web experiences
Stars
8,804Last commit
14 hours agoLicense
MIT
Drag-and-drop interface for creating and optimizing digital experiences, with headless CMS and powerful integrations.
Open Source Alternative to:
Fast, flexible VPN replacement with zero-trust security
Stars
9,039Last commit
12 hours agoLicense
Apache-2.0
Replace your VPN with zero-trust access built on WireGuard. Fast, scalable network security with simple policies and identity provider integration.
Open Source Alternative to:
Open-source A/B testing and feature flagging platform
Stars
8,140Last commit
11 hours agoLicense
MIT
Powerful, developer-friendly experimentation tool for data-driven product decisions. Seamless integration, real-time insights, and flexible deployment.
Open Source Alternative to:
Full-stack observability without code changes
Stars
7,881Last commit
2 days agoLicense
Apache-2.0
Coroot simplifies system monitoring by providing metrics, logs, traces, and profiling with zero instrumentation, leveraging eBPF technology.
Open Source Alternative to:
Secure, customizable e-signatures for modern businesses
Stars
6,885Last commit
2 days agoLicense
AGPL-3.0
A powerful, open-source e-signature solution offering customization, integration, and enhanced security for businesses of all sizes.
Open Source Alternative to:
Build and play games inside a game engine that runs live
Stars
6,410Last commit
13 hours agoLicense
MIT
A game creation platform built on Valve's Source 2 engine, letting you build, share, and play games without leaving the environment.
Open Source Alternative to:
The tensor database for AI data
Stars
9,226Last commit
3 months agoLicense
Apache-2.0
Deep Lake is an open-source database for storing, querying and managing complex AI data like images, audio, and embeddings.
Open Source Alternative to:
Modular auth, payments, emails, and analytics for your product
Stars
6,842Last commit
16 hours agoLicense
Unknown
Self-hostable platform combining user auth, payments, email, and analytics into modular building blocks that fit around your existing product.
Open Source Alternative to:
Simplify expense management for businesses of all sizes
Stars
5,009Last commit
11 hours agoLicense
MIT
Automate expense reporting, reimbursements, and corporate card management with real-time data sync and powerful integrations.
Comprehensive monitoring and incident management platform
Stars
7,487Last commit
11 hours agoLicense
Apache-2.0
All-in-one solution for uptime monitoring, incident management, and status pages to keep your services running smoothly
Open Source Alternative to:
Simple yet powerful CI/CD engine with great extensibility
Stars
7,724Last commit
11 hours agoLicense
Apache-2.0
Open-source CI/CD platform using Docker containers for pipeline execution. Create multiple workflows, extend with plugins, and enjoy free lifetime access.
Open Source Alternative to:
Voice-to-text that works offline, privately, on any app
Stars
5,599Last commit
11 hours agoLicense
MIT
Dictation app powered by OpenAI Whisper and NVIDIA Parakeet. Runs locally on macOS, Windows, and Linux with zero data retention and 100+ language support.
Open Source Alternative to:
Open-source serverless CMS for modern web projects
Stars
8,033Last commit
13 hours agoLicense
MIT
A powerful, scalable platform for building custom websites and apps with serverless architecture, offering flexibility and cost-efficiency.
Open Source Alternative to:
Visual app builder that integrates with your existing codebase
Stars
6,964Last commit
20 hours agoLicense
MIT
Open-source visual editor for building websites and web apps. Connect to any data source, design custom UIs, and ship production React code without leaving your stack.
Open Source Alternative to:
Security-first diagramming with no login required
Stars
7,617Last commit
17 hours agoLicense
Apache-2.0
Create professional diagrams online or offline with security-first approach. No registration needed. Works with Google Drive, SharePoint, Atlassian, and more.
Open Source Alternative to:
InfluxDB – The purpose-built time series platform for high-velocity ingestion and real-time queries at scale.
InfluxDB
CodeRabbit
Capture