Leon Zaher, Developer in Zagreb, Croatia
Leon is available for hire
Hire Leon

Leon Zaher

Verified Expert  in Engineering

Software Engineer and Developer

Zagreb, Croatia

Toptal member since October 9, 2023

Expertise
Back-end DevelopersDockerGolangJavaKubernetesRedisLinuxDevOpsSQLAWSMySQLPostgreSQLMongoDBNoSQL
Bio

Leon has over four years of experience as a software engineer, excelling in back-end development and DevOps. His three years of expertise in Go and two years in Java are complemented by proficiency in various other technologies. Leon's forte is crafting high-performing and resilient systems underpinned by a dedication to well-architected and tested code. His extensive experience predominantly revolves around remote work in SaaS startups, working on varying-scale projects.

Portfolio

1NCE
Go, Kubernetes, Docker, Amazon Web Services (AWS), Kubernetes Operators
Freelance Clients
Go, DigitalOcean, DigitalOcean API, API Integration, Metabase, PostgreSQL...
Platform.sh
Go, MySQL, SQL, Redis, Docker, GitLab CI/CD, Docker Compose, CI/CD Pipelines...

Experience

  • Back-end - 7 years
  • Go - 4 years
  • Docker - 4 years
  • DevOps - 4 years
  • Software Architecture - 3 years
  • SQL - 2 years
  • Kubernetes - 2 years
  • Amazon Web Services (AWS) - 2 years

Availability

Part-time

Preferred Environment

Docker, Kubernetes, MacOS, JetBrains, Go

The most amazing...

...thing I've developed was a Go service meant to be deployed on-premise by enterprise customers and used by some of the world's largest companies.

Work Experience

Software Engineer

2024 - PRESENT
1NCE
  • Led a 3-person development team on a project for an automated deployment and configuration system for VPN instances, consisting of three microservices. Key responsibilities included architecture design, technical decision-making, and team coordination.
  • Implemented key features on a project that implemented a Kubernetes controller responsible for routing traffic between IPSec pods.
  • Worked in a multi-project team responsible for multiple back-end projects and around 10 microservices.
Technologies: Go, Kubernetes, Docker, Amazon Web Services (AWS), Kubernetes Operators

Software Engineer

2023 - 2024
Freelance Clients
  • Contributed to the digital transformation of an insurance sales company. Built an internal customer and work planning portal. The portal included features for customer management, insurance plan comparison, and document storage.
  • Built a data analytics platform integrated with the customer portal to enable automated commission calculation, upsell opportunity insights, and detailed aggregated reports based on sales.
  • Focused on deploying and configuring servers, lambda functions, databases, network load balancers, and domain registrars using Docker and DigitalOcean.
Technologies: Go, DigitalOcean, DigitalOcean API, API Integration, Metabase, PostgreSQL, Python, Lambda Functions, JavaScript, Back-end, DevOps

Software Engineer

2022 - 2023
Platform.sh
  • Handled implementation and architectural decisions for a service that automated enterprise client onboarding and configuration, eliminating manual work for multiple teams.
  • Collaborated with cross-functional teams to develop authentication, authorization, and organization management services.
  • Conducted code reviews and participated in design discussions.
Technologies: Go, MySQL, SQL, Redis, Docker, GitLab CI/CD, Docker Compose, CI/CD Pipelines, DevOps, Back-end

Software Engineer

2020 - 2022
LicenseSpring Software
  • Created an on-premise service for license management with multiple deployment options, such as .exe, Docker, and Helm, used extensively by enterprise customers in mission-critical environments.
  • Developed a service for managing Kubernetes workloads using the Kubernetes Controller API.
  • Drove improvements to authentication and observability across all teams and services.
  • Interacted directly with clients to provide support and help with troubleshooting, effectively meeting their needs through solution architecture ownership.
  • Managed a GitOps-based Kubernetes cluster containing observability services and CI/CD workflows across multiple projects.
Technologies: Go, Redis, Docker, Kubernetes, Helm, Amazon Web Services (AWS), GitLab CI/CD, Flux CD, HTML, JavaScript, CI/CD Pipelines, DevOps, Back-end

Software Engineer

2019 - 2020
Determ
  • Optimized external API data ingestion, yielding a threefold surge in throughput.
  • Created a service that enables customers to automate actions based on specific events.
  • Enhanced the website scraping service, significantly improving data coverage.
  • Deployed and integrated a tool for static code analysis via CI.
  • Owned deployed services and contributed to team design meetings and planning.
Technologies: Java, MongoDB, Docker, Apache Kafka, Back-end

Software Engineering Intern

2018 - 2019
Amazon.com
  • Developed a service for error analysis and alerting, leading to a reduction in support workload.
  • Resolved critical bugs across multiple core services.
  • Improved maintainability of a key service by refactoring and adding two new APIs.
  • Took ownership of deployed changes and resolved any subsequent issues.
  • Participated in design meetings and contributed to task planning and estimations.
Technologies: Java, MySQL, Amazon Web Services (AWS), Elasticsearch, Back-end

Software Engineering Intern

2017 - 2018
Photomath
  • Developed a highly scalable service to efficiently process and store telemetry and user feedback from over 10 million phone devices.
  • Contributed to the company's hiring process by creating and grading tasks for data analyst interviews.
  • Designed and implemented data-cleaning processes using similarity algorithms via ETL protocols.
Technologies: Java, MongoDB, Google BigQuery, Google Cloud Platform (GCP), Back-end

Experience

Kubernetes Certificates as a Service

Developed a back-end service utilizing the Kubernetes Controller API. This service enables users to seamlessly automate a Secure Socket Layer (SSL) for their Kubernetes clusters by integrating their cluster with the service. This service was established as a SaaS and deployed for public accessibility.

Education

2015 - 2019

Bachelor's Degree in Computer Science

University of Zagreb - Zagreb, Croatia

Skills

Libraries/APIs

DigitalOcean API

Tools

GitLab CI/CD, Docker Compose, Helm, JetBrains, Jira, Kubernetes Operators

Languages

Go, Java, SQL, HTML, JavaScript, Python

Platforms

Docker, Kubernetes, Amazon Web Services (AWS), Linux, Google Cloud Platform (GCP), Apache Kafka, DigitalOcean, MacOS, AWS Lambda

Storage

Redis, MySQL, PostgreSQL, MongoDB, NoSQL, Elasticsearch, Amazon S3 (AWS S3)

Paradigms

DevOps

Other

Back-end, Software Architecture, CI/CD Pipelines, API Integration, Computer Science, Flux CD, Google BigQuery, Metabase, Lambda Functions

Collaboration That Works

How to Work with Toptal

Toptal matches you directly with global industry experts from our network in hours—not weeks or months.

1

Share your needs

Discuss your requirements and refine your scope in a call with a Toptal domain expert.
2

Choose your talent

Get a short list of expertly matched talent within 24 hours to review, interview, and choose from.
3

Start your risk-free talent trial

Work with your chosen talent on a trial basis for up to two weeks. Pay only if you decide to hire them.

Top talent is in high demand.

Start hiring