Ceyhun is available for hire
Hire CeyhunCeyhun Kerti
Verified Expert in Engineering
Data Engineering Developer
Istanbul, Turkey
Toptal member since March 10, 2022
Bio
Ceyhun is a data engineer with experience in various industries and technologies. His primary goal is to introduce the latest technology and methodologies to his customers at the minimum cost and maximum stability. Ceyhun enjoys working in interdisciplinary fields using hybrid technology stacks.
Portfolio
Plan A
Python, Amazon Web Services (AWS), Pandas, Dash, PostgreSQL, AWS Lambda...
Spotify - Main
Data Engineering, Scala, Java, Python, Cloud, Apache Beam, Dataflow Programming...
Screen Seventeen
Python, Apache Airflow, PostgreSQL, Amazon S3 (AWS S3), Presto...
Experience
- Python - 17 years
- Data Engineering - 17 years
- ETL - 16 years
- SQL - 15 years
- JavaScript - 8 years
- Scala - 4 years
- Go - 3 years
- Apache Beam - 1 year
Availability
Full-time
Preferred Environment
Python, SQL, ETL, Data Engineering
The most amazing...
...project I've developed is a score calculation platform for sustainable development growth that represents a step forward for a better future for humanity.
Work Experience
Data Engineer
2023 - 2024
Plan A
- Developed data pipelines to calculate carbon emissions from business activity data.
- Created API endpoints for dynamic carbon emissions calculation and management of metadata for emission conversion factors.
- Implemented reference pipelines in Snowflake and dbt.
- Designed a real-time emission calculation system using Elixir/Flow to handle concurrency with minimal resource overhead.
Technologies: Python, Amazon Web Services (AWS), Pandas, Dash, PostgreSQL, AWS Lambda, Amazon S3 (AWS S3), Apache Airflow, Snowflake, DuckDB, Elixir, FastAPI, Terraform, Streamlit, Data Build Tool (dbt), Polaras, Git, GitHub, GitHub Actions, Terragrunt, Google BigQuery, Big Data, Google Cloud Platform (GCP)
Data Engineer
2022 - 2023
Spotify - Main
- Developed an ad tracking system that measures how much of an ad is listened to by the unique user and how many ads are listened to in the content. Calculated related metrics and impressions used by downstream systems like finance and reporting.
- Fixed bugs in the system and worked on the usual small-scale tasks on the sprint.
- Prepared RFCs and reference implementations to improve the stability and reliability of the pipelines.
- Involved in planning to add dbt to our data pipeline stack, which was already used by other teams with whom we interact.
Technologies: Data Engineering, Scala, Java, Python, Cloud, Apache Beam, Dataflow Programming, Google BigQuery, Luigi, Druid.io, Data Pipelines, REST APIs, Postman, Data Integration, API Integration, Apache Spark, Kubernetes, Terraform, Data Build Tool (dbt), BigQuery
Senior Data Engineer Consultant
2021 - 2022
Screen Seventeen
- Developed ETL pipelines from different data providers to AWS S3.
- Created an SDK for the data science team so they can easily access and wrangle data from different sources.
- Maintained ETL pipelines in Apache Airflow and helped the data science team to package their flows.
Technologies: Python, Apache Airflow, PostgreSQL, Amazon S3 (AWS S3), Presto, Amazon Web Services (AWS), Data Pipelines, Flask, REST APIs, Postman, Data Integration, Prefect, API Integration, Apache Spark, Kubernetes, Terraform
Senior Data Engineer Consultant
2020 - 2021
BBVA Garanti Bank
- Created and implemented data pipelines for loan risk reports.
- Implemented a couple of fast-track projects related to customer interactions.
- Analyzed the underlying infrastructure and existing pipelines and created possible restructuring guidelines.
Technologies: SQL, PL/SQL, Oracle Data Integrator (ODI), Data Pipelines, REST APIs, Postman, Data Integration
Senior Data Engineer Consultant
2020 - 2021
Fiat
- Created an ETL pipeline between IoT source systems and Azure Blob Storage.
- Identified problems in the existing ETL pipelines and developed and maintained optimized data pipelines.
- Processed unstructured data in Azure with Spark and created structured models.
- Conducted training sessions for employees of the company.
Technologies: Python, Azure, Databricks, Delta Lake, Cassandra, PySpark, Azure Databricks, Data Pipelines, REST APIs, Postman, Data Integration, Apache Spark
Full-stack Engineer Consultant
2020 - 2021
ING Bank
- Implemented a web UI for the internal lending grid optimization tool.
- Maintained and packaged the application to be easily deployed to different platforms.
- Made the demo and showcase of the application for different company branches in other countries.
Technologies: JavaScript, Python, Flask, Pandas, Data Pipelines, REST APIs, Postman, Data Integration, API Integration, Apache Spark
Senior Data Engineer Consultant
2020 - 2021
Medical Park
- Developed ETL pipelines for real-time reporting and BI infrastructure.
- Made implementation data transfer modules between SQL Server and PostgreSQL.
- Implemented data ingestion and real-time reporting features in KSQL/Kafka.
Technologies: Python, ETL, PostgreSQL, Oracle, SQL, MySQL, Data Pipelines, REST APIs, Postman, Data Integration, API Integration
Senior Data Engineer Consultant
2019 - 2021
ING Bank
- Developed real-time ETL pipelines for the client.
- Created dynamic AI model visualization infrastructure in Python with Plotly.
- Helped to maintain and enhance existing ETL pipelines between the core system and Spark cluster.
Technologies: Python, SQL, ETL, Apache Airflow, Plotly, Data Pipelines, REST APIs, Postman, Data Integration, API Integration, Apache Spark
Senior Data Engineer Consultant
2016 - 2021
CK Energy
- Implemented high-performance ETL pipelines for the company and its subsidiaries.
- Managed an outsourced team for the business intelligence and data warehouse tasks.
- Created a web-based management software for the ETL pipeline manager so that the company can manage all the flow once for all subsidiaries.
- Optimized existing ETL pipelines and reduced the total ETL time.
Technologies: ETL, SQL, Oracle Data Integrator (ODI), Scala, JavaScript, MySQL, Data Pipelines, REST APIs, Postman, Data Integration
Senior Data Engineer Consultant
2016 - 2021
Aksigorta
- Developed highly scalable ETL pipelines for the client in SQL, Python, and Oracle Data Integrator (ODI).
- Made the transition from old ETL pipelines to a new data integrator.
- Involved in preprocessing and masking customers' sensitive healthcare data.
- Implemented highly optimized data extraction utility.
- Provided training sessions in SQL, ODI, and Python to various departments in the company.
- Optimized the current ETL pipelines and reduced the total ETL time.
- Implemented a near-realtime ETL pipeline so the company and its agencies can see the reports and insights with a 2-minute delay.
- Created a basic implementation of data integration with other companies where the client has data exchange agreements, like some hospitals, subsidiary banks, etc. Used DBT and Airflow for integration and workflow management.
Technologies: SQL, ETL, Oracle Data Integrator (ODI), Apache Airflow, Python, Apache Sqoop, MapR, MySQL, Data Pipelines, Flask, REST APIs, Postman, Data Integration, API Integration, Apache Spark, Data Build Tool (dbt)
Senior Data Engineer Consultant
2016 - 2019
Dicle Energy
- Developed ETL pipelines in SQL and Oracle Data Integrator (ODI).
- Managed and trained a team of between 10 and 15 people.
- Implemented highly optimized data extraction utility.
Technologies: SQL, Python, Data Engineering, ETL, Oracle Data Integrator (ODI), MySQL, Data Pipelines, REST APIs, Postman, Data Integration
Data Engineer
2006 - 2016
Oracle
- Developed highly scalable ETL pipelines with big data for different companies in the telecommunication industry, including Vodafone, Turkish Telecom, Avea, and Turkcell.
- Created both internal and client-facing applications.
- Mentored junior developers to enjoy software development and produce high-quality applications.
Technologies: Python, SQL, Java, Scala, ETL, Business Intelligence (BI), Data Warehouse Design, Data Warehousing, MySQL, Data Pipelines, Flask, REST APIs, Postman, Data Integration, API Integration, Apache Spark, Data Analysis
Experience
Fast Oracle to CSV Extraction Utility
https://github.com/ceyhunkerti/oracle_tocsvA fast Oracle to CSV extraction utility that extracts data from an SQL query to a CSV file. It attempts to demonstrate how a native, focused implementation can be much faster than plugin-based, high-level data transfer tools. It runs around 3.7x faster than a plugin-based data transfer tool like Embulk, which is implemented in Java, and around x3.5x faster than an export utility of DBeaver, which is also Java-based.
Web-based SQL Query Editor
https://github.com/ceyhunkerti/owlA Web-based SQL query editor for your files, databases, and cloud storage data.
It can be used to:
• Query local cloud storage files (GCS, S3).
• Query PostgreSQL and DuckDB databases.
You can create multiple users, and each user can manage their user space (databases, connections, etc.). It also has built-in user authentication and Google OAuth support.
It can be used to:
• Query local cloud storage files (GCS, S3).
• Query PostgreSQL and DuckDB databases.
You can create multiple users, and each user can manage their user space (databases, connections, etc.). It also has built-in user authentication and Google OAuth support.
Cross-platform Plugin-based Data Transfer Tool
https://github.com/bluecolor/tractorAn open-source data ingestion tool for transferring data from and to various systems. It is an entirely plugin-based tool with concurrent design. It can run natively in the operating system without requiring additional run time, and it can be managed with CLI and a web app or REST API.
Online Data Redaction Platform
https://github.com/bluecolor/redactA platform that discovers and masks or redacts the data in different database management systems such as Oracle, MySQL, and SQL Server. It is designed for companies to comply with GDPR requirements. It has a Python back end and web UI to manage the application.
Task Scheduler
https://bluecolor.github.io/octopus/A concurrent task scheduler and workflow platform that is easy to install and manage. It is horizontally scalable with a strong dependency management engine. Its design dates back to a time when airflow was not in the scene and was not as popular as it is today.
Education
2001 - 2006
Bachelor's Degree in Computer Science Engineering
Yeditepe University - Istanbul, Turkey
Skills
Libraries/APIs
Pandas, REST APIs, Luigi, PySpark, Terragrunt
Tools
Apache Airflow, Postman, Plotly, Apache Sqoop, AWS CloudFormation, Prefect, Apache Beam, Terraform, Git, GitHub, BigQuery
Languages
Python, Go, JavaScript, SQL, Snowflake, Java, Scala, Bash Script, Elixir, TypeScript, Zig, C
Frameworks
Flask, Apache Spark, Presto, Spark, Ruby on Rails (RoR), Streamlit
Paradigms
ETL, ETL Implementation & Design, Dataflow Programming, Business Intelligence (BI)
Platforms
Oracle, Oracle Data Integrator (ODI), Amazon Web Services (AWS), Kubernetes, Oracle Database, Databricks, MapR, Azure, AWS Lambda, Docker, Linux, Google Cloud Platform (GCP)
Storage
Databases, PL/SQL, Druid.io, MySQL, Data Pipelines, Data Integration, Oracle PL/SQL, PostgreSQL, Amazon S3 (AWS S3), Cassandra
Other
Data Engineering, Scripting, Google BigQuery, Data Build Tool (dbt), API Integration, Data Analysis, Data Modeling, Data Analytics, Data Transformation, Data Migration, Data Science, Delta Lake, Cloud, Azure Databricks, Data Warehouse Design, Data Warehousing, Dash, DuckDB, FastAPI, Computer Science, Polaras, GitHub Actions, CSV, Big Data
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