Lisssen & Co

Lisssen & Co was a digital audio platform and creator ecosystem built to stream high-fidelity audio, connect listeners with creators, and provide audio distribution tools.

I served as a Full-Stack Software Developer, responsible for core platform engineering. My mandate covered three main pillars:

1. Building a responsive custom audio player engine capable of seamless, low-latency playback, waveform visualization, and buffer management across desktop and mobile browsers.
2. Developing full-stack feature APIs and database models using the MERN (MongoDB, Express, React, Node.js) stack.
3. Provisioning, securing, and maintaining the platform's production server infrastructure on Linux (Ubuntu) and AWS (Lightsail & S3) without a dedicated DevOps team.

1. Web Audio Engine & Custom Playback Optimization

Engineered a custom audio player abstraction layer on top of HTML5 <audio> and the Web Audio API, paired with Redux state orchestration:

• Adaptive Chunk Preloading & Range Requests: Implemented byte-range HTTP request handling (Range: bytes=...) from server to client, allowing instantaneous playback initiation without waiting for full audio files to download.
• Buffer Strategy & Re-buffering Protection: Designed a prefetching algorithm in Redux to buffer upcoming queue tracks in memory, eliminating gaps between track transitions.
• Waveform & Seeking Performance: Abstracted audio scrubbing into a non-blocking UI task using requestAnimationFrame, preventing frame drops during rapid playback seeking.

[ User Action ] ──> ( Redux Queue Manager ) ──> ( HTML5 / Web Audio API )
                                                        │
                                                        ▼
[ AWS S3 Storage ] <── ( Signed Range Requests ) <── ( Express API Proxy )

2. MERN Stack Feature Architecture

• MongoDB & Mongoose Schemas: Modeled complex audio metadata, user playlists, listening histories, and artist permissions with indexing strategies for fast query execution.
• Express.js REST APIs: Authored endpoints for file upload validation, user authentication (JWT), track streaming metadata, and social interaction handling.
• React & Redux UI: Built dynamic dashboards for listeners and creators, leveraging Redux Toolkit to maintain centralized player state across all site routes.

3. Self-Managed Linux & AWS Infrastructure

• AWS Lightsail & Nginx: Configured and maintained Ubuntu Linux server instances on AWS Lightsail. Built Nginx reverse proxy configurations with SSL termination (Let's Encrypt), Gzip/Brotli compression, and rate-limiting rules.
• Process & Health Management: Used PM2 and Systemd services for continuous process monitoring, environment variable isolation, and automated service auto-restarts.
• AWS S3 & Media Security: Designed secure asset storage where private audio files were stored on S3 and served exclusively via short-lived signed URLs generated by the Node.js backend.