Jakub K.

Senior Software Engineer

Poznań, Poland

Experience

Mar 2023 - Sep 2025
2 years 7 months

Senior Software Engineer

Brightline Freight Corp

  • Led design and launch of a modular omnichannel retail platform to unify online/in-store flows, improving conversion and throughput by 22% using Docker, AWS and microservices patterns.
  • Built real-time inventory sync to prevent oversell and reduce latency by 40ms on average, implemented with Kafka, PostgreSQL, and event-driven Python workers for reliability.
  • Implemented secure RAG pipelines for product recommendations to protect PII and model context, integrating LLM guardrails and automated unit tests in CI/CD.
  • Authored automation for container lifecycle and hardening policies to meet compliance, using Docker, Kubernetes, and scripted scans in Bash to reduce drift by 30%.
  • Designed schema and configuration layers to support client-specific features, decreasing client onboarding time by 45% and enabling multi-tenant customizations with Redis.
  • Integrated observability and auto-scaling with AWS metrics and custom health probes, increasing uptime to 99.95% and reducing incident MTTR by 36%.
  • Collaborated with product and security teams to perform regular threat modeling and prompt injection tests against deployed agents, using automated Python test harnesses and red-team playbooks.
Jan 2021 - May 2023
2 years 5 months

Senior Software Engineer

Mphasis

  • Delivered an analytics platform for campaign sentiment using Elasticsearch and stream processing to surface trends within minutes, improving marketing reaction time by 60%.
  • Built high-throughput ingestion pipelines with Kafka and FastAPI microservices to process millions of events daily, increasing throughput by 48% while maintaining sub-second processing.
  • Led integration of automated CI/CD security checks into pipelines, enforcing image scanning and secret detection with Docker, GitLab CI, and policy-as-code to reduce vulnerabilities by 35%.
  • Implemented model evaluation harnesses and adversarial prompt tests against internal LLM agents to detect prompt injection and data leakage, formalizing an OWASP Top 10 for LLMs checklist for the team.
  • Coordinated cross-functional builds of dashboards and APIs for clients using React and server APIs, improving data-driven decisions and lowering report generation time by 40%.
  • Automated post-deployment validation and canary rollouts to reduce rollback frequency, using scripted health checks in PowerShell and Bash across environments.
  • Mentored engineers on secure coding and threat modeling for AI features, advising on RAG privacy controls, input sanitization, and agent policy enforcement strategies.
Jun 2019 - Dec 2020
1 year 7 months

Software Engineer

FLUX Inc.

  • Designed internal frameworks to automate secure payment flows and tokenization in a FinTech context, reducing reconciliation errors by 28% using Docker containers.
  • Implemented rule validation engines to enforce business logic and compliance, built in Python with strict test coverage and runtime assertions for auditability.
  • Created tools for partners to onboard payment modules with automated tests and deployment templates, decreasing integration time by 50% and improving reliability.
  • Developed secure APIs and rate limiting to protect merchant endpoints from abuse, employing PostgreSQL, token-based auth, and API gateway policies for resilience.
  • Led security reviews and assisted in penetration testing across web and API layers, coordinating fixes for OWASP Top 10 issues and hardening endpoints.
  • Built CI pipelines with automated static analysis and dependency checks to catch vulnerabilities early, integrating with Jenkins and container scanning tools.
May 2015 - May 2019
4 years 1 month

Junior Software Engineer

Grab Holdings

  • Architected billing and analytics components to support global operations, improving invoice accuracy and reducing disputes by 18% via robust logging and reconciliation.
  • Built real-time data transformation pipelines for reporting using Spark and Python, accelerating report generation and enabling near real-time operational metrics.
  • Implemented auditable processes and secure data handling patterns to meet compliance needs, documenting procedures and improving traceability across systems.
  • Supported cross-team integrations and maintained high-quality code through peer reviews and automated tests, contributing to platform stability during rapid growth.

Summary

Senior Software Engineer with 10+ years designing backend systems and secure platforms across E-commerce, Advertising, FinTech and EdTech domains. Strong expertise in building containerized services, automation and CI/CD, conducting AI red-teaming, and integrating Python based tooling for evaluation and security.

Languages

English
Advanced

Education

Oct 2011 - Jun 2015

National Taiwan University

Bachelor of Computer Science · Computer Science · Taipei, Taiwan, Province of China

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