Data Engineer
OpenTag Open · verified Oct 24, 2026 At a glance
Mid-level Data Engineering role at OpenTag. Sofia · full-time.
Pay not stated Data Engineer salary
dataroles summary, based on the employer's posting.
What you'll do
- Build and look after dependable data pipelines with clear structure
- Shape complex datasets around business needs, including both functional and technical requirements
- Automate manual data work, speed up delivery and help the platform scale
- Create SQL and BI components to move data from varied sources through extraction, transformation and loading
- Support analytics and build tools that help analysts and data scientists improve their work
What you bring
- You understand relational database concepts, including table relationships, isolation levels, and CAP and ACID
- You have practical PostgreSQL experience and can write, tune and optimize SQL queries
- You know ETL practices and data warehouse design, including performance optimization
Who this fits
This mid-level role suits a data engineer focused on SQL, PostgreSQL and data pipeline work. The position is based in Sofia, Bulgaria, with a hybrid setup.
From the employer
OpenTag is a well-funded international company within the field of Sports Betting and iGaming.
Our mission is to create the best software through empowered teams, centralized around our product. We do this to help great organizations reach ambitious goals and fulfill their purpose with equally great teams.
Our platform is built in Golang and Java (Spring Boot), with a modern data ecosystem that powers analytics and business intelligence across our products. We take pride in innovation, engineering excellence, and continuous improvement.
We're looking for a Middle Data Engineer to join our R&D team and help build, optimize, and maintain our data platform. You'll work closely with internal stakeholders and B2B clients to deliver ad-hoc data solutions, develop and improve ETL pipelines, and ensure reliable, high-quality data for business needs.
Requirements:
Good understanding of relational database logic. I.e. differences between CAP and ACID, types of relations between tables, isolation levels etc.
Hands-on experience with PostgreSQL.
Proficiency in query authoring (SQL).
Working knowledge of procedures and functions.
Experience with performance and tuning of SQL queries.
Good understanding of de-normalized/normalized data.
Solid understanding of ETL logic.
Good understanding of DWH principles and DWH performance optimization.
Nice to have technical qualifications:
Experience with Python
Experience with NoSQL databases.
Experience with data tools: DBT.
Basic experience with stream-processing systems: Kafka, Storm, Spark-Streaming, etc.
Basic experience with GitLab CI/CD pipelines
Day-to-day responsibilities:
Build and maintain reliable, well-structured data pipelines.
Assemble large, complex data sets that meet functional / non-functional business requirements.
Contribute to internal process improvements: automating manual processes, optimizing data delivery, and improving scalability.
Build the components required for optimal extraction, transformation, and loading of data from a wide variety of data sources using SQL and BI technologies.
Support the development of analytics tools that utilize the data pipeline to provide actionable insights into customer acquisition, operational efficiency and other key business performance metrics.
Create data tools for analysts and data scientists that will assist them in building andoptimizing our product into an innovative industry leader.
What do We offer?
An inspiring workspace with awesome teammates and a great vibe
Learning opportunities with a dedicated training budget to level up your skills
25 vacation days + an extra day off to celebrate your birthday 🎉
Premium health insurance for your peace of mind
Birthday vouchers and little surprises along the way
Free snacks, team lunches, and great coffee (because fuel matters ☕)
Sports card, transportation, and food allowance
Quarterly team events that bring everyone together
Excited to join us? Click the Apply button and let’s build something amazing together!
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