- Building and designing REST API using Flask- Using SQLAlchemy as ORM for working with PostgreSQL database- Redesigning/building data warehouse system in PostgreSQL from scratch for storing large amount of data coming from different sources- Worked on scraping system for extracting data through REST APIs or Selenium for ETL purposes- Integration with Twilio SendGrid to send data into system through emails- Working with custom user datasets as one of many sources of data (e.g. copying spreadsheets and saving it into DWH)- Building scalable service for executing and scheduling long-running and intensive background jobs using Celery (task queue implementation in Python enabling multiple workers to run in multiple threads)- Working with large files and big data as well as storing them using AWS S3- Building CLI tools to interact with the system besides REST API using click- Working with web sockets to utilise real-time communication with frontend- Working with Redis as a backend for Celery and utilising it for caching to improve performance of application- Building report system for sending job reports via email by using AWS SES- Building token-based public API to fetch dataset's data and load them as JSON or CSV (integrations with Google Sheets IMPORTDATA function, Google Data Studio, etc)- Building report system which allows users to write raw SQL queries (using PostgreSQL syntax) to access data from DWH (similar to Amazon Athena)

- Building rest API to monitor status of websites using Ruby on Rails and PostgreSQL- Building service for executing background jobs with Redis and Sidekiq