Harish Mittal, Developer in Tampa, FL, United States
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Harish Mittal

Verified Expert  in Engineering

Data Engineer and Developer

Tampa, FL, United States
Toptal Member Since
February 24, 2022

Harish is an expert in data engineering transformation projects with 20+ years of experience architecting and implementing data-related enterprise systems in finance, telecommunications, and health insurance domains. He excels in Python, C++, Java, AWS, Oracle, Redshift, and Snowflake. With leadership and consulting experience at PennyMac, Citi, and Verizon, Harish is well-versed in managing all aspects of enterprise-level projects, including architecture, budgeting, planning, and delivery.


Freelance Client
Amazon Web Services (AWS), Amazon Athena, AWS Lambda, AWS Glue, Redshift...
AWS Lambda, Amazon Athena, SQL, Pandas, Stock Market...
Amazon Web Services (AWS), Amazon Athena, AWS Glue, AWS Lambda...




Preferred Environment

Amazon Web Services (AWS), Linux, Data, Python 3, Data Engineering

The most amazing...

...work I've done was to design and develop an application to use real-time stock market data and perform algorithmic trading on the Interactive Broker platform.

Work Experience

Senior Data Engineering Consultant

2022 - PRESENT
Freelance Client
  • Worked as a lead data migration consultant to migrate data from the on-premise Microsoft SQL Server data warehouse to AWS Redshift.
  • Led the initial discovery phase with customers and designed an E2E approach to migrate data warehouse and business intelligence from on-premise SQL Server to AWS Redshift using various AWS technologies.
  • Wrote Python code in AWS Lambda and Glue and created scheduled jobs using EventBridge.
Technologies: Amazon Web Services (AWS), Amazon Athena, AWS Lambda, AWS Glue, Redshift, Amazon RDS


2019 - PRESENT
  • Designed and developed an application for stock market data analysis, developed strategies to find bullish and bearish trends in stocks and ETFs and used many TA-Libs.
  • Built the ETL pipelines to collect tick data (per day, four hours, and five seconds) and fundamentals for over 3,000 stocks, ETFs, futures, and SPACs using many APIs and web scrapers.
  • Transformed data calculated technical indicators, such as EMA crossover, stochastic, RSI, CCI, AO, candles, and Fibonacci levels.
  • Integrated Cathie Wood's ARK ETF daily trade data and developed views to quickly see ARK holdings and action trends.
  • Made the entire dataset and research available through a website to help users make investment decisions.
  • Developed a trading app to use real-time tick data (OHLCV) and place trades using IB-API on the Interactive Broker platform. Also developed and tested strategies using backtest.
Technologies: AWS Lambda, Amazon Athena, SQL, Pandas, Stock Market, Algorithmic Trading Analysis, Python, Interactive Brokers API, Stock Trading, Futures & Options


2021 - 2022
  • Led the implementation of a cloud data warehouse using AWS and Snowflake technologies.
  • Built ETL pipelines for mortgage loan campaigns, advertising, and marketing from Google, Facebook, Salesforce, Blend, Leadspedia, and more.
  • Fetched data using APIs and AppFlow to AWS S3, cleansed the data using Lambda, and pushed it to Snowflake using stored procedures and external tables.
Technologies: Amazon Web Services (AWS), Amazon Athena, AWS Glue, AWS Lambda, Data Engineering, Linux, Snowflake, Python

Senior Vice President

2011 - 2020
  • Managed ETL and BI teams (25 members) to re-engineer a legacy HR data warehouse and business intelligence platform.
  • Delivered a new in-house human capital management data warehouse platform that consolidated all HR verticals under one system with centralized data security, fast time to market, and advanced analytics using MicroStrategy BI.
  • Developed data migration strategy, measurable acceptance criteria, and implemented frameworks and tools to track progress toward go-live.
  • Architected the data validation framework, which helped reduce the testing cycle from two weeks to one day.
  • Designed the data reconciliation framework used to compare more than 400 batch feeds and resulted in $1.2 million in savings for two years.
Technologies: Data Warehousing, Data Analytics, Data Transformation, Reporting, Business Intelligence (BI), IT Management

Tech Lead

2000 - 2011
  • Designed, developed, and managed the operations support system (OSS) to support Verizon's high-speed internet services.
  • Wrote C++ code on Unix to process orders and provision services.
  • Developed the Java code to take orders and manage inventory of telecom equipment.
  • Built custom data migration (ETL) modules using Java, JDBC, SQL, and Oracle and migrated data from many companies Verizon bought.
Technologies: Oracle, Unix, C++, Shell Scripting, Perl, Workflow

Algorithmic Trading, OHLCV Data Processing, Strategy Development, and Backtesting

I recently developed a Python application to process real-time streaming tick data (OHLCV), performed TA calculations, and built a strategy to place automated trades using IB API on the Interactive Brokers platform. I also developed other approaches and ran multiple backtests to analyze and improve them.

Apart from that, I developed a batch application to source daily tick data for 3,000+ stocks and detect bullish and bearish trends using many TA-Libs. Processed data to calculate diverse technical indicators, such as EMA crossover, stochastic, RSI, CCI, AO, candle types, Fibonacci levels, and 52-week high or low monthly and weekly performance for the batch application. Used Jupyter Notebook with Matplotlib to develop strategies and perform backtesting. Integrated Cathie Wood's ARK ETF daily trading data. Made the entire data set and research available via a website to help users make investment decisions.


Python 3, SQL, C++, Java, Python, Snowflake, Perl


Amazon Athena, AWS Glue, Git


AWS Lambda, Linux, Oracle, Unix, Amazon Web Services (AWS)


Amazon S3 (AWS S3), Data Pipelines, MySQL, Redshift


IT Management, Data Engineering, Computer Science, Data Warehousing, Data Analytics, Data Transformation, Reporting, Stock Trading, Stock Market, Stock Price Analysis, Quantitative Analysis, Algorithmic Trading Analysis, Shell Scripting, Workflow, Amazon Route 53, API Gateways, Cloud, Amazon RDS, Futures & Options


Pandas, Interactive Brokers API


Business Intelligence (BI), ETL

1990 - 1994

Bachelor's Degree in Computer Science

Nagpur University - Nagpur, Maharashtra, India


AWS Certified Data Analytics Specialty


MAY 2020 - MAY 2023

AWS Certified Solutions Architect Associate


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