Open Source Projects using Kotlin
A curated collection of the 61 best open source software using Kotlin. Find the most popular and trending open source projects to learn from, contribute to, or use in your own projects.
Secure email, calendar and contacts with end-to-end encryption
Stars
7,866Last commit
2 days agoLicense
GPL-3.0
Tuta offers encrypted email, calendar and contacts with quantum-resistant security, protecting your privacy without ads or tracking.
Open Source Alternative to:
Secure, encrypted notes for your digital life
Stars
6,598Last commit
5 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:
Navigate anywhere with detailed offline maps and GPS
Stars
5,923Last commit
11 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:
Free office suite with Microsoft compatibility
Stars
4,262Last commit
12 hours agoLicense
GPL-3.0
Complete free office suite compatible with Microsoft formats (.doc, .docx, .xls, .xlsx, .ppt, .pptx). Open source alternative with regular updates.
Open Source Alternative to:
Serverless team chat over Tor, no phone number needed
Stars
2,640Last commit
2 days agoLicense
GPL-3.0
Quiet is a peer-to-peer messaging app that syncs messages directly between devices over Tor, with no central server, no phone number required, and no metadata leaks.
Open Source Alternative to:
Business rules engine with AI, visual flows, and audit trails
Stars
1,938Last commit
2 days agoLicense
MIT
Model business logic in decision tables, visual flows, and natural-language rules. Change rules without deploys, test every path, and run the same engine anywhere.
Open Source Alternative to:
Track your TV shows and movies on Android
Stars
2,146Last commit
2 days agoLicense
Unknown
Android app for tracking TV shows and movies you're watching, have watched, or plan to watch, powered by TMDb data.
Open Source Alternative to:
Create custom spaces to chat, game, and connect globally
Stars
1,578Last commit
13 hours agoLicense
MIT
Build your own community space for gaming, chatting, and hanging out with friends worldwide. Customize your environment for the perfect social experience.
Open Source Alternative to:
Unify APIs, databases, and services effortlessly
Stars
1,253Last commit
14 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:
Track TV shows and movies, synced with Trakt.tv
Stars
1,449Last commit
2 months agoLicense
GPL-3.0
Android and iOS app for tracking TV shows and movies, managing watchlists, and syncing viewing history with Trakt.tv across devices.
Open Source Alternative to:
Build AI agents and automate complex workflows seamlessly
Stars
992Last commit
17 hours agoLicense
Apache-2.0
Create intelligent automation workflows combining AI agents with your favorite apps and services. Connect, automate, and scale your operations without complex coding.
Open Source Alternative to:
Secure open source email with advanced encryption & AI
Stars
647Last commit
3 days agoLicense
AGPL-3.0
Open source professional email solution with PGP encryption, JMAP protocol, AI-powered responses, and advanced antispam protection. Control your data privately.
Open Source Alternative to:
Track games, movies, anime, manga, and books in one place
Stars
511Last commit
3 days agoLicense
MIT
Cross-platform collection manager for retro games, movies, TV shows, anime, manga, visual novels, and books with tier lists, visual boards, and import/export.
Open Source Alternative to:
Fast, secure, and privacy-focused web browsing
Stars
385Last commit
19 hours agoLicense
MPL-2.0
Midori Browser is a lightweight, fast, and secure browser that protects users' privacy, available for Windows, Linux, and Android.
Open Source Alternative to:
Connect APIs, databases, and streams without glue code
Stars
360Last commit
2 months agoLicense
Unknown
Automated data integration platform that connects APIs, databases, and event streams using semantic schemas. Deploy secure integrations in minutes with Git-based workflows.
Open Source Alternative to:
Decentralized CAPTCHA for enhanced web security
Stars
298Last commit
3 days agoLicense
Apache-2.0
A blockchain-based CAPTCHA solution offering improved security, user experience, and resistance to bot attacks for web applications.
Open Source Alternative to:
Securely save and access your favorite links across devices
Stars
105Last commit
4 months agoLicense
MIT
A privacy-focused bookmark manager that encrypts your saved links, allowing you to access them anytime, anywhere, on any device with complete control.
Open Source Alternative to:
End-to-end encrypted location sharing for groups
Stars
53Last commit
21 days agoLicense
AGPL-3.0
Share your real-time location with family and friends using end-to-end encryption, geofence alerts, travel history, and multi-device tracking.
Open Source Alternative to:
Privacy-focused note-taking made simple and fast
Stars
67Last commit
7 months agoLicense
GPL-2.0
Justnote is a secure note-taking app that lets you easily create and sync notes across devices while maintaining full control of your data.
Open Source Alternative to:
Capture – Capture screenshots, generate PDFs, scrape content, extract metadata, and automate browsers with one API.
Openlane
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