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Born in Rostock, I've been coding since my teenage years, which eventually led me to earn a Master's in IT from the University of Helsinki. My career has been a steady climb from backend engineer to full stack lead, with a strong emphasis on complex, regulated industries like fintech and healthcare. I thrive on the challenge of making brittle legacy systems talk to modern, cloud-native stacks, and I get a real kick out of optimizing a slow API or designing a resilient data pipeline. Outside of work, I'm probably tinkering with home automation or exploring the Baltic coast, always looking for that perfect balance between system design and the simple things in life.…Born in Rostock, I've been coding since my teenage years, which eventually led me to earn a Master's in IT from the University of Helsinki. My career has been a steady climb from backend engineer to full stack lead, with a strong emphasis on complex, regulated industries like fintech and healthcare. I thrive on the challenge of making brittle legacy systems talk to modern, cloud-native stacks, and I get a real kick out of optimizing a slow API or designing a resilient data pipeline. Outside of work, I'm probably tinkering with home automation or exploring the Baltic coast, always looking for that perfect balance between system design and the simple things in life.

Daniel Roisch

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Born in Rostock, I've been coding since my teenage years, which eventually led me to earn a Master's in IT from the University of Helsinki. My career has been a steady climb from backend engineer to full stack lead, with a strong emphasis on complex, regulated industries like fintech and healthcare. I thrive on the challenge of making brittle legacy systems talk to modern, cloud-native stacks, and I get a real kick out of optimizing a slow API or designing a resilient data pipeline. Outside of work, I'm probably tinkering with home automation or exploring the Baltic coast, always looking for that perfect balance between system design and the simple things in life.…Born in Rostock, I've been coding since my teenage years, which eventually led me to earn a Master's in IT from the University of Helsinki. My career has been a steady climb from backend engineer to full stack lead, with a strong emphasis on complex, regulated industries like fintech and healthcare. I thrive on the challenge of making brittle legacy systems talk to modern, cloud-native stacks, and I get a real kick out of optimizing a slow API or designing a resilient data pipeline. Outside of work, I'm probably tinkering with home automation or exploring the Baltic coast, always looking for that perfect balance between system design and the simple things in life.

Available to hire

Born in Rostock, I’ve been coding since my teenage years, which eventually led me to earn a Master’s in IT from the University of Helsinki. My career has been a steady climb from backend engineer to full stack lead, with a strong emphasis on complex, regulated industries like fintech and healthcare. I thrive on the challenge of making brittle legacy systems talk to modern, cloud-native stacks, and I get a real kick out of optimizing a slow API or designing a resilient data pipeline. Outside of work, I’m probably tinkering with home automation or exploring the Baltic coast, always looking for that perfect balance between system design and the simple things in life.

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Work Experience

Senior Full Stack Engineer at SONIA | HealthTech, AI & SaaS

September 1, 2021 - Present

Designed and delivered Node.js REST APIs, PostgreSQL data models, and React/TypeScript applications for AI-assisted healthcare workflows, reducing average workflow processing time from 18 minutes to 4.5 minutes (75% improvement). Integrated LLMs, speech recognition, and voice processing pipelines by converting raw audio and clinical data into structured inputs, reducing manual processing time by ~120 hours per month. Optimized PostgreSQL queries, API payloads, and asynchronous processing paths for frequently accessed workflows, reducing median API response time from 340 ms to 85 ms and improving responsiveness by 75%. Led a small team of 4 engineers, translating requirements into technical tasks, reviewing PRs, resolving blockers, and coordinating delivery of 8 major releases/features across frontend, backend, and AI integration. Built and maintained AWS-based containerized production services with Kubernetes and CI/CD while introducing monitoring, validation, and failure-handling patt

Full Stack Developer at SYNEKTIK | MedTech & HealthTech

May 1, 2018 - August 31, 2021

Developed backend services and REST APIs using PHP and Java for radiology, diagnostic, and patient-information workflows, optimizing database access to reduce selected API response times from 620 ms to 145 ms (77% improvement). Built React and Angular interfaces for clinical dashboards and medical-data workflows by restructuring reusable UI components and frontend data handling to reduce repeated implementation effort. Integrated with DICOM and HL7-based healthcare systems to process medical imaging metadata and patient information, reducing failed integration requests by ~68% through validation and structured error handling. Designed and optimized PostgreSQL/MSSQL schemas and queries for patient records, imaging metadata, and operational information to reduce complex retrieval times. Implemented automated tests, logging, and production diagnostics across frontend and backend services, helping identify integration failures faster and reduce recurring production defects by 55%.

Backend Developer at HOLVI | FinTech, Digital Banking & Financial Services

July 1, 2016 - April 30, 2018

Developed Python and Django backend services for business accounts, invoicing, bookkeeping, and payment-processing workflows, optimizing Django ORM queries and service logic to reduce selected API response times. Built and maintained REST APIs for SEPA transfers, financial transactions, expense workflows, and account operations, supporting ~85,000 transactions per month while preserving validation and transaction consistency. Investigated recurring payment-processing bugs caused by duplicate callbacks/retries and inconsistent transaction states, tracing issues through logs and database records and implementing idempotency and validation controls that reduced duplicate-processing incidents. Implemented backend logic for KYC, AML, token-based authentication, and transaction auditing, reducing failed or incorrectly validated account-processing cases. Improved transaction logging, error handling, and service reliability for externally integrated financial workflows hosted on AWS.