Work
Lead Software Engineer
@ Klarna · Card & Banking Domain 04/2022 — Present- ▪ Led the architecture & implementation of a high-performance risk and fraud banking decision engine — tens of thousands of req/s at <300/100 ms SLA/SLO.
- ▪ Designed an ETL pipeline for banking deposits data supporting regulatory reporting across 45M+ records spanning 12 years.
- ▪ Directed centralization of a company-wide consumer-banking data-platform hub covering financial/regulatory reporting, capital & liquidity, AML/KYC, bookkeeping and analytics.
- ▪ Re-architected Lakehouse integration from queue-based to file-based, cutting processing time from 24–48h to 1–2h.
Senior Back-End Developer
@ Mobivate Limited 11/2021 — 03/2022- ▪ Migrated a legacy Python 2 project to a modern async distributed system, cutting server response time by 50%.
- ▪ Refined data-quality measures to 99.9% accuracy with rigorous validation, improving BI reliability.
- ▪ Revamped back-end systems & APIs with monitoring and real-time tracking, cutting downtime by 15%.
Back-End Developer
@ StarLabs 09/2020 — 11/2021- ▪ Migrated a Django monolith into async FastAPI microservices, improving API response time by 20%.
- ▪ Reached 98% test coverage across seven microservices with automated test & integration frameworks.
- ▪ Led system integration of diverse data sources for BI solutions; mentored six interns over three months.
Software Engineer
@ Blackstone 11/2017 — 09/2020- ▪ Led design of an in-house robotic framework (NAOqi & QiSDK): language-agnostic, modular, async and event-driven.
- ▪ Integrated Google Speech-to-Text on SoftBank robots, improving accuracy up to 60%.
- ▪ Built and streamlined the technical hiring & interview pipeline.
Skills
Projects
# live: two products I build and run
shieldsign/
An ESIGN-compliant e-signature platform for sending, signing & verifying legal documents: multi-document envelopes, bulk sends, team workspaces, MFA and webhooks, producing tamper-evident, independently verifiable signed documents.
osmoni/
A trilingual (DE/EN/SQ) marketing site for a facility-services company in Homburg/Saar, with a custom Bootstrap design system, language-prefixed routing, a web-based translation UI, and SEO, accessibility & GDPR compliance built in as first-class features.
About
I’m a software engineer based in Berlin, currently leading work on banking risk & data systems at Klarna. My focus is the unglamorous core that has to be right: decision engines that hold their SLA under load, data pipelines that reconcile, and platforms teams can actually build on.
I started in robotics, building an event-driven framework for SoftBank humanoids, and have since worked across fintech and BI, from monolith-to-microservice migrations to company-wide data-platform consolidation. I care about correctness, observability, and systems that stay simple as they scale.
“Hasan Prishtina”
Let’s build something solid.
Open to conversations about backend, data-platform and infrastructure work. Drop me a line below, or reach me directly.