Marcel Pieper portrait
Available for freelance projects

Marcel Pieper

Data Systems and Full Stack Product Development

I build and modernize complex systems where reliability and maintainability matter: performance-heavy pipelines, authorization/validation architecture, and internal platforms that help teams move faster. I work comfortably from deep backend design to operational full-stack product execution.

Upwork LinkedIn GitHub
Python logoPython
TypeScript logoTypeScript
Pandas logoPandas
FastAPI logoFastAPI
Django logoDjango
Laravel logoLaravel
React logoReact
Next.js logoNext.js
SQL databases logoSQL
AWS logoAWS
Selenium logoSelenium
GitHub Actions logoGitHub Actions

What I bring

Backend & data platform ownership

Pipeline re-architecture, query optimization, deployment safety, and long-term system maintainability in production.

Authorization, validation, and auditability

Engine-based permission models, migration-safe rollouts, and correctness-focused validation for trust-critical domains.

Full-stack operational products

Admin and internal tooling that reduce manual work, improve visibility, and connect clean UX with robust backend workflows.

Professional timeline

2024 – Present TradingHours (Primary client)

Backend & full-stack developer with architectural ownership

Led critical architecture and platform modernization across shared backend services, admin systems, website/API, and Python package delivery.

  • Re-architected core data pipeline and achieved roughly 20x performance gains.
  • Implemented zero-downtime deployment and failure-safe rollback mechanics.
  • Centralized fragmented permission logic into an auditable engine-based system.
  • Modernized export/mapping and internal Data Insights/admin workflows.
2024 Physician Health Program of BC

Healthcare data extraction pipeline

Built automated scraping and validation workflows to synchronize physician data into CRM systems at significant scale.

  • Extracted and normalized data from dynamic sources for 10,000+ physician records.
  • Integrated validation and cleansing, including support for unstructured inputs.
2024 Freelance client project

Real-time monitoring and extraction system

Developed continuous Selenium-driven monitoring, dynamic interaction handling, and structured Excel exports for operational reporting.

2024 Education industry client

AI-assisted PDF validation and extraction

Built a local processing tool to extract and validate student report components, producing clean summaries for operational use.

  • Automated checks across 5-page reports for 600 students, processed twice yearly.
  • Improved consistency and reduced manual review effort.
2024 – Present Music app client

Full-stack maintenance and delivery

Delivered React/Django improvements, backend fixes, and deployment automation for ongoing production stability.

2023 – 2024 ZippedScript

Backend developer — enterprise API platform

Built and maintained enterprise scraping API infrastructure with strong validation and operational tooling.

  • Implemented Selenium grid operations, end-to-end verification, and MFA challenge handling.
  • Migrated framework from Flask to Django and SQLAlchemy models to Django ORM without service disruption.
2021 – 2023 pandas_market_calendars (Open source)

Contributor and release manager

Contributed performance and feature improvements to trading-calendar infrastructure used in financial workflows.

  • Optimized a key date-range function by 37x using vectorized approaches.
  • Improved handling of historical trading-hour changes and release processes.