Open Source Projects using Kotlin
A curated collection of the 67 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.
Fast, flexible VPN replacement with zero-trust security
Stars
9,122Last commit
13 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:
A team of AI agents in a chat app, on your own machine
Stars
Stars growing quickly over the last 30 days5,499Last commit
12 hours agoLicense
Apache-2.0
Run a team of AI agents locally on your own API keys and subscriptions, with scheduled tasks, computer use, and Gmail, GitHub and Slack integrations.
Open Source Alternative to:
Simplify expense management for businesses of all sizes
Stars
5,071Last commit
11 hours agoLicense
MIT
Automate expense reporting, reimbursements, and corporate card management with real-time data sync and powerful integrations.
Secure email, calendar and contacts with end-to-end encryption
Stars
8,039Last commit
16 hours 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
6,681Last commit
17 hours 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
6,105Last 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:
Free office suite with Microsoft compatibility
Stars
Stars growing over the last 30 days4,552Last commit
11 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:
Webhook delivery platform with retries, security, and a portal
Stars
3,462Last commit
11 hours agoLicense
MIT
Add customer-facing webhooks to your product without building the infrastructure. Handles retries, signatures, multi-tenancy, filtering, and monitoring at scale.
Open Source Alternative to:
Serverless team chat over Tor, no phone number needed
Stars
2,658Last commit
5 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
Stars growing over the last 30 days2,087Last commit
3 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:
Create custom spaces to chat, game, and connect globally
Stars
Stars growing over the last 30 days2,001Last commit
22 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:
Track your TV shows and movies on Android
Stars
2,167Last commit
8 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:
Local-first 2FA authenticator and password manager
Stars
1,543Last commit
5 days agoLicense
GPL-3.0
Open-source authenticator and password manager that stores 2FA tokens and passwords locally on your device, with zero-knowledge encryption and no account required.
Open Source Alternative to:
Unify APIs, databases, and services effortlessly
Stars
1,282Last commit
13 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
1,469Last commit
2 days 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
Stars growing over the last 30 days1,044Last commit
11 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:
Track games, movies, anime, manga, and books in one place
Stars
Stars growing over the last 30 days591Last 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:
Secure open source email with advanced encryption & AI
Stars
660Last commit
19 hours 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:
Fast, secure, and privacy-focused web browsing
Stars
409Last commit
12 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:
Decentralized CAPTCHA for enhanced web security
Stars
305Last commit
15 hours 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:
Connect APIs, databases, and streams without glue code
Stars
360Last commit
4 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:
End-to-end encrypted location sharing for groups
Stars
76Last commit
2 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:
Securely save and access your favorite links across devices
Stars
107Last commit
6 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:
Turn short shortcuts into your everyday words
Stars
57Last commit
1 day agoLicense
AGPL-3.0
Text expander that replaces typed abbreviations with saved replies, signatures, and snippets across macOS, Windows, and Linux.
Open Source Alternative to:
Privacy-focused note-taking made simple and fast
Stars
67Last commit
9 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:
Postiz – The All-in-One agentic social media scheduling tool
Sent
Bright Data