Cally

Cally is a unique social app that connects strangers for random 10-minute phone calls, encouraging authentic conversations and serendipitous connections. The app breaks down social barriers and provides a platform for people to share stories, perspectives, and experiences.

Key Features

• Random Matching: Implemented intelligent matching algorithm that pairs users randomly while considering preferences like language, interests, and conversation topics.
• 10-Minute Timer: Built countdown timer system that limits each call to 10 minutes, creating focused conversations and preventing awkward endless calls.
• Voice Calling: Integrated high-quality voice calling infrastructure enabling clear, low-latency conversations between matched users.
• Interest Tags: Created interest-based tagging system allowing users to specify topics they'd like to discuss, improving match quality and conversation flow.
• Safety Features: Implemented reporting, blocking, and moderation tools to maintain a respectful and safe environment for all users.
• Beautiful UI: Designed engaging interface with smooth animations, intuitive controls, and a welcoming aesthetic that encourages usage.

Technical Implementation

Built with Flutter focusing on real-time communication and user experience:

• WebRTC integration for peer-to-peer voice calling
• Real-time matching system with queue management
• Timer implementation with accurate countdown and notifications
• Custom UI animations for engaging transitions
• Permission handling for microphone access

Challenges & Solutions

Ensuring call quality across different network conditions required implementing adaptive bitrate and connection quality monitoring with graceful degradation.

Creating a balanced matching system that's both random and relevant was solved through a weighted algorithm considering user preferences while maintaining serendipity.