Coindhan

Overview

Worked as a Backend Engineer at a small cryptocurrency trading platform, with ownership across trading systems, P2P infrastructure, APIs, third-party integrations, and parts of the application frontend.

The engineering team consisted of a Senior Software Engineer, a Frontend Engineer, a Designer, an HR professional, and me as the Backend Engineer. Working in a small team gave me end-to-end ownership of the systems I built, from design and implementation through testing and production reliability.

Key Contributions

• *Built the arbitrage trading system- using Ruby on Rails and Redis. The system compared prices across different cryptocurrency platforms and executed buy/sell trades when price differences created an arbitrage opportunity, with Redis used for real-time state and execution.

• *Engineered the Constant Trade system- to handle large buy and sell requirements without significantly moving the market price. Instead of placing a large order at once, the system continuously executed smaller trades based on the current market price while targeting slightly better execution prices. This allowed orders to be fulfilled throughout the day while reducing the impact of large orders on the market.

• *Built the P2P trading platform- using Ruby on Rails and AWS Step Functions. The system provided an alternative trading flow for users and coordinated the different steps involved in P2P transactions.

• *Built and maintained production APIs- using Ruby on Rails, backed by a combination of MySQL and DynamoDB depending on the workload and data requirements.

• Integrated third-party KYC providers, including HyperVerge and Paysharp, implementing the API integrations and the end-to-end verification flow required by the platform.

• *Implemented retry and error-handling mechanisms- around external services and financial workflows to handle network failures and transient errors more reliably.

• *Contributed to the frontend- of the application when required, working across the stack in a small engineering team.

• Owned systems end-to-end, including implementation, test-case coverage, manual testing, debugging, and production readiness.

Technologies

• Ruby on Rails
• Redis
• MySQL
• DynamoDB
• AWS Step Functions
• REST APIs
• Background Jobs
• P2P Trading
• Trading Systems
• FinTech