Open to opportunities

Grigorii Kosarev

@grigoriikosarev

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Data Engineer building dbt + Airflow data pipelines for billing, marketing, and analytics in BigQuery and ClickHouse.

Zimbabwe

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What I'm looking for

I’m looking to keep building production data pipelines with dbt and Airflow, own data quality, and optimize reliability and cost—ideally with room to use AI/LLMs to automate workflows.

I build production-grade data platforms across fintech and adtech, including Medallion-layer (Bronze/Silver/Gold) pipelines for billing and marketing data in dbt on BigQuery and ClickHouse.

At Offergate, I led dbt as the core transformation tool for a multi-terabyte ClickHouse warehouse, then used Airflow + incremental models to cut pipeline latency and deliver fresher analytics quickly. I also re-architected the marketing analytics workflow from event tracking (GA4, GTM) into BigQuery with Tableau dashboards.

Earlier, at Kaspersky, I automated reporting with Python and SQL, integrated social-media APIs, and built time-series anomaly detection. On contract work for a high-volume payments fintech, I migrated ETL from manual operations to a robust Airflow instance and deployed an AI-powered Telegram agent to automate customer support.

Experience

Work history, roles, and key accomplishments

Current

Data Analytics Engineer

Current

Ruby Labs

Jan 2026 - Present (7 months)

Designed and implemented Medallion architecture in dbt for billing and marketing data pipelines, optimizing BigQuery costs. Established data quality checks and domain-based data ownership.

DBT BigQuery Airflow Data Modeling Data Quality

Data Engineer

Offergate

May 2024 - Jan 2026 (1 year 8 months)

Led implementation of dbt for ClickHouse warehouse, reducing transformation runtime by 18%. Built scalable Airflow pipelines and optimized ClickHouse storage for improved query performance.

DBT Clickhouse Airflow BigQuery GA4 GTM Tableau fastAPI Flask

AI Data Engineer

Confidential client

Dec 2024 - Jul 2025 (7 months)

Built data engineering practice from scratch, migrating ETL to Airflow. Developed AI-powered Telegram agent using Langchain and ChatGPT API, reducing operational costs by 40%.

Airflow Lang Chain ChatGpt Python Data Modeling Data Quality

Web Data Engineer

Kaspersky

Jan 2022 - May 2024 (2 years 4 months)

Developed ETL pipelines using Python and SQL, automated reporting, and implemented time-series anomaly detection. Managed web analytics with GTM and built PowerBI dashboards.

Python Pandas NumPy SQL BigQuery GTM Power BI A B Testing Google Optimize

Software/Data Engineer

Flowwow

Jun 2023 - Aug 2023 (2 months)

Developed asynchronous Telegram bot for orders and marketing broadcasts. Containerized service with Docker and set up CI/CD. Implemented Grafana and PostgreSQL for monitoring and analytics.

Aiogram Docker GitHub Actions Grafana PostgreSQL Python