Freelancer profile translated to English.
Back to original languageAbout Grigorios Konstantinos
Hello, I'm Konstantinos — Data Analyst & BI Consultant 👋
I spent nearly two years in operational teams, called in as backup when reporting descended into chaos: duplicates, manual Excel trackers, dashboards no one trusted anymore. My role was to make the numbers reliable: write SQL to build clean data models, automate what was done manually, and deliver Power BI, Tableau, and Metabase dashboards that were actually used for decision-making. 🧑💻
This work constantly brought me back to the same question: why does a "simple" dashboard take so long to build, and why does it break so often? So, in my free time, I learned the technical layer underneath — Python, dbt, Airflow, Databricks — and built a complete pipeline, from raw API data to a production-grade lakehouse (NutriChain Food Lakehouse), the same architecture used by modern data teams.
I don't present myself as an engineer who has never delivered reporting. I am a data analyst and BI consultant who now understands what happens under the hood — which means fewer broken dashboards, faster delivery, and reporting that doesn't collapse at the first source change.
Need someone to clean up reporting, build a dashboard from scratch, or simply get a clear answer on what your data can really tell you? That's what I do. Contact me. 💬
Greek
Native or bilingual
French
Fluent
English
Fluent
Spanish
Native or bilingual
Portuguese
Conversational
Can work on-site
Paris (up to 10km)
Experience
- FileButlerCo-Founder & Data AnalystNovember 2025 - Today (9 months)• - Own end-to-end analytics for the product: built and maintain dashboards in Metabase tracking user activity using SQL against our production database.• - Rebuilt broken GA4 tracking and event structure, then set up export pipeline from Google Analytics to BigQuery for deeper, SQL-based analysis beyond GA's native reporting limits.• - Write and optimize SQL queries to answer product and growth questions for the founding team, replacing ad-hoc spreadsheet checks with repeatable dashboards.
- KONSTANTINOS GKARAVELOSData Analytics EngineerOctober 2025 - February 2026 (4 months)Self-taught modern data pipeline work: built NutriChain Food Lakehouse (Python ingestion, dbt, Airflow, Databricks) as a portfolio project demonstrating pipeline skills. I designed and built a production-style food data lakehouse that solves a real problem. Open Food Facts is a public API with 3M+ product records but zero analyst-ready tables. Nutrichain Open Food Lakehouse is a portfolio project demonstrating my skills in analytics engineering. It turns that raw API into a trusted, queryable lakehouse on Databricks
- Becton, Dickinson and CompanyData AnalystMEDICALAugust 2025 - October 2025 (2 months)Paris, FranceContracted to execute a critical master data integration project following a company acquisition, specifically handling the Greek and French markets:- Tasked with identifying and resolving duplicate customer records between an 8,000-record acquired database and a 514,000-record enterprise database- Engineered custom Excel macros and utilized advanced data functions to automate the matching of customer names, addresses, and IDs across both datasets- Successfully mapped and deduplicated the required records, ensuring a clean migration into the parent company's master database
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Education
- Diploma in IT Applications & Computer SciencePublic Vocational Training Institute of Glyfada2021Grade: 9,5/10 I was 1st student in the class and my main areas of study were: -Website & Database building -Data Warehousing & ETL process -Data Visualisation (Power BI, Tableau) -Computers' architecture -Operating systems -Coding in C language, Python (Pandas, NumPy, Matplotlib)
- Honors Bachelor in Business, Economics, Marketing & AnalyticsAthens University of Economics and Business2021Grade: 8,55/10 Activities and societies: Member of ESN AUEB, Debater of Rhetorical association AUEB, Member of Film association AUEB -Top 5% of graduates -Specialization in Analytics -Admitted 1st to the department with a 91% score in Greek National Exams -The most interesting and influential courses during my studies were: Negotiations, Product Design & Development, UX/UI Design, Digital Entrepreneurship, Web analytics, Creative Design & Advertising Media, Corporate Ethics and Responsibility
Certifications
- Business Intelligence & Machine LearningCode.Hub2025
- Introduction to Database Systems & SQLTech Talent School2020