Portfolio

Data Systems & Automation
Additional work from earlier projects: SQL-backed workflows, batch jobs, APIs, validation checks, and reproducible outputs that can be run and reviewed again.
  • Shared definitions and validation so downstream jobs read the same data contracts
  • Batch workflows with deterministic outputs, versioned artifacts, and clear failure paths
  • APIs, monitoring, and review artifacts that make data products easier to operate

I care about data systems that stay understandable after the first run: where definitions live, how inputs are validated, what gets written out, and how another person can audit the result. These repositories focus on pipelines, API boundaries, batch automation, data quality, and reproducible artifacts. Smaller interactive utilities sit on Data tools.

GitHub profile — opens everything public on my account. On this page, each project card links to that repo and its live demo in the footer.

Flagship Projects

Active career flagships in development, aligned with my hiring focus. These are in-progress builds, not completed case studies yet.

Operational Analytics · In Development

Prague Public Transport Operations Intelligence System

  • SQL
  • Python
  • PostgreSQL
  • Data Quality
  • KPI Design
  • Power BI

An end-to-end analytics system that transforms public transport data into validated operational metrics, analytical models, and interactive Power BI reporting.

Geospatial Analytics · In Development

Urban Accessibility & Service Coverage Intelligence

  • Python
  • GeoPandas
  • PostGIS
  • Spatial SQL
  • QGIS
  • Network Analysis

A spatial analysis system for identifying areas with limited access to essential urban services by combining population, transport, and service-location data.

Workflow Automation · In Development

AI-Assisted Data & Operations Intelligence System

  • Python
  • LLM APIs
  • Structured Outputs
  • Function Calling
  • Validation Guardrails
  • Workflow Automation

An automated workflow system that integrates LLM structured outputs and database lookups with strict validation guardrails, audit logging, and human approval gates.

SQL & Data Modelling · In Development

Retail Analytics Warehouse & Metrics System

  • SQL
  • dbt
  • PostgreSQL
  • Dimensional Modelling
  • Data Testing
  • Data Quality

A SQL-first analytical warehouse that transforms transactional commerce data into tested dimensional models and reusable business metrics.

Additional Work

Feature store (mini)

  • pandas
  • pytest
  • FastAPI
  • Batch pipeline
  • Data contracts

Built a deterministic feature-table workflow with one definitions registry, schema checks, and repeatable batch builds.

Batch compile turns raw extracts into a versioned feature table under locked column specs and validation rules. Training, scoring, and review paths all read the same built artifact instead of duplicating transform logic.

System skill: Shared data definitions, schema validation, repeatable batch compilation

Review focus: Inspect the definitions registry, validation checks, CLI build path, API transform endpoint, and tests.

Boundary: Not an enterprise feature platform; intentionally scoped to a small, reviewable feature-table workflow.

Batch scoring pipeline

  • Python
  • Batch
  • pandas
  • pytest
  • joblib

Built a scheduled data workflow with aligned preprocessing, deterministic row outputs, and CLI-friendly failure handling.

Batch job processes CSV rows with a fixed preprocessing path and writes score, label, model version, and timestamp on each row. Built for scheduled runs with audit-friendly outputs and explicit failure exits.

System skill: Scheduled file processing, deterministic outputs, run metadata, failure handling

Review focus: Inspect CLI behavior, preprocessing path, output schema, manifest handling, and failure exits.

Boundary: Scoring is batch-first; the live page is an I/O showcase, not the runtime job scheduler.

Data quality & monitoring pipeline

  • pandas
  • pytest
  • Streamlit
  • PSI / KS
  • JSON schema

Built a batch monitoring workflow for schema, drift, and prediction-quality checks with generated review artifacts.

Validates each incoming batch against a fixed reference and surfaces shifts in inputs, categories, and prediction patterns. Emits batch-level reports and structured artifacts so changes can be reviewed without rerunning ad hoc notebooks.

System skill: Schema checks, drift detection, batch-level reporting, review artifacts

Review focus: Inspect the baseline/current batch comparison, generated HTML/JSON artifacts, thresholds, and test coverage.

Boundary: Covers batch-file monitoring only; no streaming, Kafka, per-request logging, or retraining loop.

This page lists additional work: each card carries its GitHub repository and live-demo URL in one place. I update links when a repo moves or a deploy URL changes.

© 2026 Vahdet Karataş. All rights reserved.
Data analysis, data systems, automation, and geospatial applications.