Senior Backend Engineer

Pawel Jendrusik

Senior backend engineer with 13+ years of experience designing payment platforms and regulated financial systems across FinTech, banking, and crypto. Strong JVM background in Scala with deep expertise in event-driven systems and PostgreSQL-backed transaction flows.

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Profile

Proven track record in backend API design, transactional workflows, and integrations with external payment service providers. Comfortable delivering secure, scalable infrastructure in cross-functional product teams.

Core Expertise

  • Payment APIs: payments, payouts, refunds, FX, withdrawals
  • PSP and card issuer integrations
  • Transaction lifecycle modeling and state machines
  • Idempotency, retries, and failure handling
  • Event-driven backend systems (Kafka, RabbitMQ)
  • Relational data modeling (PostgreSQL)

Payments & Backend Focus

  • Ownership of backend APIs for payment and payout flows
  • Asynchronous payment orchestration using Kafka
  • PostgreSQL transactional models with auditability guarantees
  • Operational safety and correctness in regulated environments
  • Close collaboration with product, compliance, and infrastructure teams

Selected Work

  • Designed KYC/KYB onboarding flows for compliant account opening.
  • Delivered transaction monitoring systems for regulated crypto flows.
  • Built centralized market-data and exchange-rate services.
  • Implemented Travel Rule data exchange and compliance reporting pipelines.

Technical Skills

Scala JavaScript TypeScript PHP ZIO Cats Akka Akka-HTTP sttp Tapir PostgreSQL Kafka RabbitMQ Docker Kubernetes (GCP) CI/CD Linux

Professional Experience

ICEO LAB LTD – Linity, BeOne

Senior Software Engineer · 02.2023 – Present · London, United Kingdom

  • Core backend contributor for payments, withdrawals, FX conversion, and balance management.
  • Designed KYC/KYB onboarding flows for compliant account opening and execution.
  • Built Kafka-driven services for payment state changes, balance updates, and KYC lifecycle events.
  • Modeled PostgreSQL schemas with idempotency, retries, and auditability.
  • Operated market-data and exchange-rate services used by payment and FX flows.

BITCLEAR AG

Senior Staff Software Engineer & Manager · 04.2019 – 01.2023 · Ruggell, Liechtenstein

  • Led development of a crypto-enabled payment processing platform under strict regulation.
  • Built wallet infrastructure, payment services, and transaction monitoring systems.
  • Delivered KYC/KYB and risk-profiling platforms with approval workflows.
  • Integrated AML and blockchain analytics providers and implemented Travel Rule pipelines.

BITMONEY.EU – Crypto Limited

Lead Software Engineer · 05.2016 – 04.2019 · Malta

  • Built an FX-enabled platform for buying and selling Bitcoin with credit cards.
  • Integrated multiple PSPs and optimized routing to reduce processing costs.
  • Designed transaction flows, order matching, and settlement processes.
  • Owned Android and iOS app delivery with an external vendor.

Previous Experience

  • VALUELOGIC / SCOUT24 — Backend development (PHP / Symfony)
  • LIMANGO.PL — Lead developer for e-commerce platform
  • ALLEGRO GROUP – CENEO.PL — Backend development for price comparison
  • PLAYARENA.PL — Sports event management platform

Education

  • MSc. Computer Science, Wroclaw University of Science & Technology (2014)
  • BSc. Computer Science, Wyzsza Szkola Informatyki i Zarzadzania "Copernicus" (2012)

Languages

  • Polish (native)
  • English (professional)