09/11/2026 updated

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Senior Backend & DevOps Engineer | AWS, Kubernetes, Terraform | Python & Node.js

Warszawa, Poland
Only remote
Bachelor of Science (B.Sc.) in Computer Science - Warsaw University of Technology
Warszawa, Poland
Only remote
Bachelor of Science (B.Sc.) in Computer Science - Warsaw University of Technology

Profile attachments

Walerian_Polak_Resume.pdf

About me

Senior Backend & DevOps Engineer with 9+ years of experience building scalable APIs, microservices, and cloud infrastructure. Expert in Python, Node.js, AWS, Kubernetes, Docker, Terraform, CI/CD, and observability, delivering secure, reliable, production-ready systems.

OAuth 2.0GitHub ActionsServerlessHelmGCPIAMSupabaseJava (Programming Language)JavaScriptApplication Programming Interfaces (APIs)Amazon Web ServicesMicrosoft AzureCloud EngineeringLinuxDevOpsDjangoPython (Programming Language)PostgreSQLMongoDBMySQLNGINXNode.jsRedisElastic LogstashAnsiblePrometheusDataOpsServer-SideTypeScriptWebSocketDatadogS3 BucketLoad BalancingCloud Platform SystemEvent-driven ArchitectureFlaskLarge Language ModelsExpress.jsGrafanaSpring BootCachingAWS LambdaInfrastructure as Code (IaC)AWS VPCBackendAWS ECSGitFastAPIEvent Driven ArchitectureBackend ProgrammingKubernetesDeployment AutomationFull Stack DevelopmentApache KafkaFront End Software DevelopmentApi DesignCloudwatchApi GatewayNestJSRestful ApiTerraformAWS EKSDockerElk StackJenkinsGolangMicroservices
Backend Development: Python, Node.js, TypeScript, JavaScript, Go, Java, FastAPI, Django, Flask, Express.js, NestJS, Spring Boot, REST API, GraphQL, WebSockets, Microservices, Distributed Systems, Event-Driven Architecture, API Design, Backend Architecture
Database & Data: PostgreSQL, MySQL, MongoDB, Redis, Elasticsearch, DynamoDB, SQL Optimization, Database Design, Data Modeling, Database Migration, Caching, Replication
Cloud Platforms: AWS, Microsoft Azure, Google Cloud Platform (GCP), EC2, ECS, EKS, Lambda, S3, RDS, CloudWatch, IAM, VPC, Load Balancing, Auto Scaling, Cloud Architecture, Serverless Architecture
DevOps & Infrastructure: Docker, Kubernetes, Terraform, Helm, Ansible, Infrastructure as Code (IaC), Linux, Nginx, Git, GitHub Actions, GitLab CI/CD, Jenkins, ArgoCD, CI/CD Automation, Deployment Automation, Infrastructure Provisioning, Configuration Management
Kubernetes: Kubernetes Architecture, EKS, AKS, GKE, Helm Charts, Ingress, Services, Deployments, StatefulSets, ConfigMaps, Secrets, Autoscaling, Kubernetes Networking, Container Orchestration, Cluster Management
CI/CD & Release Engineering: GitHub Actions, GitLab CI/CD, Jenkins, Docker Build Pipelines, Automated Testing, Deployment Pipelines, Blue-Green Deployment, Canary Releases, Rollbacks, Release Automation, Environment Management
Monitoring & Observability: Prometheus, Grafana, ELK Stack, Elasticsearch, Logstash, Kibana, Loki, Datadog, CloudWatch, OpenTelemetry, Application Monitoring, Infrastructure Monitoring, Centralized Logging, Alerting, Performance Monitoring, Distributed Tracing
Security: AWS IAM, OAuth 2.0, OpenID Connect, JWT, RBAC, Secrets Management, API Security, Network Security, Container Security, TLS/SSL, Secure CI/CD, Vulnerability Management, Security Best Practices
Messaging & Distributed Systems: Apache Kafka, RabbitMQ, Redis Streams, Message Queues, Event-Driven Systems, Asynchronous Processing, Pub/Sub, Distributed Transactions
AI & Backend Integration: OpenAI API, Anthropic Claude, LLM Integration, AI APIs, RAG, Vector Databases, LangChain, LangGraph, AI Agents, Embeddings, Semantic Search, AI-powered Backend Services
Architecture & Engineering: Microservice Architecture, Monolith-to-Microservices Migration, High Availability, Fault Tolerance, Scalability, Performance Optimization, System Design, API Gateway, Load Balancing, Disaster Recovery, Cost Optimization
Development Practices: Git, GitHub, Code Review, Unit Testing, Integration Testing, TDD, Agile/Scrum, Jira, Confluence, Technical Documentation, Code Quality, Clean Architecture, SOLID Principles, Troubleshooting and Production Support
Frontend Integration: React, Next.js, TypeScript, API Integration, Server-Side Rendering, Authentication Integration
Professional Strengths: Technical Leadership, System Architecture, Cloud Migration, Production Deployment, Incident Troubleshooting, Performance Optimization, Infrastructure Automation, Cross-functional Collaboration

Experience

Professional experience5 - 10 years
Freelancer since2021

Languages

EnglishNative speakerPolishNative speaker

Project history

Senior Backend & DevOps Engineer

Dev and Deliver

Internet & IT

10-50 team member

  • Led backend development and cloud infrastructure for scalable web platforms, SaaS applications, and custom business systems.
  • Designed microservices and backend APIs using Node.js, TypeScript, Python, PostgreSQL, REST, and GraphQL.
  • Architected AWS environments using Docker, Kubernetes, Terraform, networking, load balancing, and managed cloud services.
  • Built production-grade CI/CD pipelines with automated testing, containerization, deployment, rollback, and release management.
  • Implemented infrastructure automation and environment provisioning using Terraform and configuration management practices.
  • Established application and infrastructure observability using metrics, centralized logging, monitoring, alerting, and distributed tracing.
  • Improved system reliability through high-availability architecture, autoscaling, health checks, resource optimization, and disaster-recovery practices.
  • Integrated AI/LLM capabilities into backend services where appropriate, including API-based model integration, semantic search, RAG, and intelligent automation.
  • Worked directly with developers, product stakeholders, and DevOps engineers to translate requirements into reliable production systems.
  • Took ownership of technical decisions, production incidents, performance optimization, cloud cost management, and continuous infrastructure improvements.

Senior Backend & Cloud Engineer

M TECHUB LLC

Internet & IT

10-50 team member

  • Architected and developed scalable backend services using Python, Node.js, TypeScript, REST APIs, PostgreSQL, and distributed-system patterns.
  • Designed and deployed containerized microservices using Docker and Kubernetes.
  • Managed cloud infrastructure and application environments across development, staging, and production.
  • Implemented Infrastructure as Code using Terraform and automated infrastructure provisioning and configuration.
  • Built and maintained CI/CD pipelines for automated testing, container builds, deployments, and rollback workflows.
  • Implemented centralized logging, monitoring, metrics, and alerting to improve production visibility and incident response.
  • Improved application availability through load balancing, health checks, autoscaling, resilient service design, and deployment automation.
  • Worked on cloud security including IAM, secrets management, network controls, TLS, and secure service-to-service communication.
  • Participated in architecture reviews and helped migrate legacy components toward containerized and cloud-native infrastructure.

Senior Backend Engineer

Holdapp

Internet & IT

10-50 team member

  • Designed and implemented backend services and automation solutions using Python, Linux, REST APIs, PostgreSQL, and open-source technologies.
  • Took ownership of backend architecture, service integration, deployment workflows, and production troubleshooting.
  • Developed CI/CD pipelines using Jenkins, Git, and automated testing to improve release consistency and deployment speed.
  • Containerized application components with Docker and supported reproducible development and production environments.
  • Worked with distributed systems and integrated multiple business applications and external services.
  • Improved deployment processes through automation, configuration management, and infrastructure standardization.
  • Diagnosed complex production issues across application, database, networking, and deployment layers.
  • Participated in technical design discussions, code reviews, architecture decisions, and mentoring of other developers.

Backend Engineer

Mad Mountain

Internet & IT

10-50 team member

  • Designed and developed backend services using Node.js, TypeScript, JavaScript, PostgreSQL, Redis, and REST APIs.
  • Built modular application components with a focus on maintainability, scalability, and clean service boundaries.
  • Developed authentication, authorization, validation, and secure API integrations for production applications.
  • Improved backend performance through database optimization, caching, asynchronous processing, and API-level improvements.
  • Worked closely with frontend engineers to define API contracts and integrate backend services with web applications.
  • Supported cloud deployments and collaborated with DevOps engineers on CI/CD, environment configuration, and release automation.
  • Investigated production issues, analyzed application logs, and implemented fixes to improve system reliability.

Backend Developer

Synphonyte

Internet & IT

10-50 team member

  • Developed and maintained backend applications using Python, Django, PostgreSQL, Redis, Celery, and REST APIs.
  • Built reusable API services and backend modules supporting web, e-commerce, and business applications.
  • Designed database models, optimized SQL queries, indexes, and caching strategies to improve application performance.
  • Implemented background processing and asynchronous workflows using Celery and RabbitMQ.
  • Worked with Linux-based environments and supported application deployment, configuration, and production troubleshooting.
  • Collaborated with frontend developers and QA engineers to integrate APIs and deliver stable production releases.
  • Participated in code reviews, debugging, testing, Git-based development, and Agile delivery.

Certificates

Certified Kubernetes Administrator (CKA)

The Linux Foundation / CNCF

2024

AWS Certified DevOps Engineer – Professional

Amazon Web Services (AWS)

2023

HashiCorp Certified: Terraform Associate (003)

HashiCorp

2021

Portfolio

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