Arnoldas Gudas, Developer in Vilnius, Vilnius County, Lithuania
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Arnoldas Gudas

Verified Expert  in Engineering

Team Leadership Developer

Location
Vilnius, Vilnius County, Lithuania
Toptal Member Since
December 6, 2019

With 19 years of experience in software engineering, Arnoldas is a passionate leader dedicated to building and managing high-performing engineering teams. His drive lies in guiding teams to implement reliable, scalable, and secure distributed systems while fostering a culture of continuous learning. Arnoldas has played pivotal roles in renowned fintech companies, including Zip Co, ZestMoney, and PhonePe, impacting over 500 million customers.

C#.NETMicrosoft SQL ServerVisual StudioWindowsGitAgileASP.NET MVCTest-driven Development (TDD)REST APIsAmazon Web Services (AWS)JavaAmazon Simple Notification Service (Amazon SNS)MySQLSpring BootLocust

Portfolio

ZestMoney
Management, Objectives & Key Results (OKRs), Platforms, Go, Java...
Zip Co
.NET, React, Kubernetes, Helm, Terraform, CQRS, Event Sourcing...
Cintra
.NET Core, Terraform, Amazon Simple Notification Service (Amazon SNS)...

Experience

C# - 15 yearsMicrosoft SQL Server - 10 yearsTeam Leadership - 9 yearsAgile - 7 yearsMicroservices Architecture - 5 yearsJava - 4 yearsAmazon Web Services (AWS) - 4 yearsAzure - 1 year

Availability

Part-time

Preferred Environment

Visual Studio Code (VS Code), Git, MacOS

The most amazing...

...thing I've built is a remote engineering center in Lithuania for a fintech startup, where I hired and managed three international teams.

Work Experience

Senior Director of Engineering

2021 - PRESENT
ZestMoney
  • Oversaw the platform engineering business unit, managing three international teams totaling 15 employees, including three engineering managers and a principal engineer.
  • Opened the engineering center for ZestMoney in Lithuania and hired 10 employees.
  • Created a vision and a long-term plan for platform engineering, which involved initiating a transformation from infrastructure operations to platform engineering and site reliability engineering (SRE).
  • Led the company's engineering initiatives like technical debt registry, revamping common libraries, decommissioning legacy services, migrating from Jenkins to GitLab, and migrating the messaging platform to Kafka.
  • Led engineering initiatives like reducing AWS cloud infrastructure costs, improving cloud security and compliance, improving observability, and others.
  • Implemented OKRs and drove a culture of continuous learning through blameless postmortems.
Technologies: Management, Objectives & Key Results (OKRs), Platforms, Go, Java, Amazon Web Services (AWS), Prometheus, Grafana, Terraform, MongoDB Atlas, cast.ai, Sumo Logic, New Relic, PagerDuty, Team Leadership, GitLab, Kubernetes, Amazon RDS, Apache Kafka, Remote Team Leadership

Senior Software Engineer II

2021 - 2021
Zip Co
  • Worked on a highly scalable platform that spans multiple continents and utilizes cutting-edge technologies and design patterns such as .NET Core, React, Kubernetes, Helm, Terraform, CQRS, event sourcing, DDD, and more.
  • Contributed to several key projects, including developer experience, reliability engineering, monitoring, and partner integration platform.
  • Designed and implemented features, improved system performance, and ensured high reliability and availability of the platform.
Technologies: .NET, React, Kubernetes, Helm, Terraform, CQRS, Event Sourcing, Domain-driven Design (DDD), Datadog

.NET Developer

2020 - 2021
Cintra
  • Helped to migrate the on-premise legacy payroll management application to the cloud by adopting REST APIs and event-based architecture on .NET5, SNS, SQS with DDD approach.
  • Focused on the back end and QA engineering, spread knowledge on development best practices and how to build with quality. Used techniques such as domain knowledge crunching, ensuring code quality through code reviews, and test pyramid.
  • Worked hand in hand with DevOps engineers creating infrastructure as a code on AWS with Terraform, Docker, Docker-compose, and Kubernetes (EKS) and automating the delivery process with CircleCI, ArgoCD, and ConfigCat.
  • Helped bring more customer value by shaping agile practices.
Technologies: .NET Core, Terraform, Amazon Simple Notification Service (Amazon SNS), Amazon Simple Queue Service (SQS), Amazon Cognito, Amazon CloudWatch, Docker, Docker Compose, Kubernetes, Amazon EKS, CircleCI, Gherkin, Microsoft SQL Server, Test-driven Development (TDD), REST APIs, RESTful Development, Event-driven Architecture, Git, Linux, Entity Framework Core, C#, Agile, Amazon Web Services (AWS), ASP.NET Core, Jira, Visual Studio Code (VS Code), Domain-driven Design (DDD), Bitbucket, .NET

Architect | Back-end Developer

2020 - 2020
E11 Capital
  • Created the microservice-based architecture design for the leading domestic worker service provider.
  • Implemented infrastructure as a code using Terraform in Azure.
  • Created a Kubernetes cluster in Azure Kubernetes Services.
  • Led back-end implementation with ASP.NET Core 3.1, overlooking two back-end developers and one platform engineer.
  • Implemented event-driven architecture with Azure Service Bus.
  • Developed an identity and access control solution using OpenID Connect and OAuth2.0 protocols.
  • Implemented continuous integration and continuous delivery (CI/CD) pipelines in Bitbucket.
  • Worked closely with React and React Native front-end developers and test engineers.
Technologies: REST APIs, RESTful Development, Microservices Architecture, Visual Studio Code (VS Code), Linux, Jira, Test-driven Development (TDD), Agile, IdentityServer 4, Git, Azure Application Insights, Bitbucket, Docker, Azure Container Registry, Helm, Terraform, PostgreSQL, Azure Blob Storage API, Azure Key Vault, Azure Service Bus, ASP.NET Core, C#, Kubernetes, Azure Kubernetes Service (AKS), Azure, Event-driven Architecture, Entity Framework Core, .NET

Team Lead

2017 - 2019
ZestMoney
  • Led a software engineering team of up to six developers.
  • Trained, coached, and did performance reviews of my team members.
  • Improved the KPIs of payments, collections, and financial operations.
  • Participated in architecture decisions of the ZestMoney platform.
  • Implemented low latency, high throughput, and scalable microservices.
  • Applied and promoted domain-driven design, test-driven design, and other best practices and principles in software development.
  • Applied DevOps, Lean, and Agile principles such as value stream mapping, continuous integration, code reviews, retrospectives, and continuous improvement in order to boost business value, quality, and technical excellence.
Technologies: Visual Studio, New Relic, Amazon Simple Queue Service (SQS), IdentityServer 4, Bitbucket, Sumo Logic, Redis Cache, Domain-driven Design (DDD), Mambu, REST APIs, RESTful Development, Web API 2, Microservices Architecture, ASP.NET, Visual Studio Code (VS Code), Linux, Amazon CloudFront CDN, Jira, Jenkins, Amazon S3 (AWS S3), AWS Lambda, Amazon API Gateway, Spring Boot, Amazon Simple Notification Service (Amazon SNS), Amazon Web Services (AWS), Test-driven Development (TDD), Agile, Git, Python, Docker, Redis, Amazon DynamoDB, MySQL, ASP.NET Core, C#, Java, Event-driven Architecture, .NET, Team Leadership, Remote Team Leadership

Software Engineer

2015 - 2017
Zest Money
  • Implemented low latency, high throughput, and scalable microservices.
  • Developed core components of the ZestMoney platform.
  • Introduced the domain-driven design approach in software development.
  • Used test-driven development to attain exceptional quality.
  • Improved work processes by conducting regular retrospectives.
Technologies: Visual Studio, Amazon Simple Queue Service (SQS), IdentityServer 4, Bitbucket, Redis Cache, Loggly, Domain-driven Design (DDD), Mambu, REST APIs, RESTful Development, Microservices Architecture, ASP.NET, Linux, Amazon CloudFront CDN, Jira, Jenkins, Amazon S3 (AWS S3), AWS Lambda, Amazon Simple Notification Service (Amazon SNS), Amazon Web Services (AWS), Test-driven Development (TDD), Agile, Git, Python, Elasticsearch, Redis, Amazon DynamoDB, MySQL, Web API 2, C#, Spring Boot, Java, Event-driven Architecture, .NET

Senior Developer/Architect

2014 - 2015
Statess
  • Developed a supplier management platform.
  • Implemented a re-architecture vision.
  • Introduced unit testing.
  • Improved branching strategy.
  • Introduced Scrum.
  • Recruited and coached the development team.
Technologies: Visual Studio, Bitbucket, JavaScript, Test-driven Development (TDD), Agile, Git, Kentico, Microsoft SQL Server, ASP.NET, C#, .NET

Application Developer

2014 - 2014
ZenithOptimedia
  • Developed internal ZenithOptimedia tools.
  • Introduced test driven development, design patterns, and SOLID principles.
  • Introduced Scrum.
  • Recruited and coached the development team of two developers and one test engineer.
Technologies: Visual Studio, JavaScript, ASP.NET, Test-driven Development (TDD), Agile, Git, Microsoft SQL Server, ASP.NET MVC, C#, .NET

Head of Engineering

2012 - 2013
Creditinfo Lietuva (part of Creditinfo International GmbH)
  • Recruited and led a software development team of up to 10 people.
  • Led the application development for issuing credit cards and consumer loans.
  • Led software development projects in credit risk management.
  • Acted as a project committee member, where all major project decisions were made.
  • Managed the IT infrastructure of the credit bureau platform.
  • Improved development and quality assurance processes.
  • Implemented ISO/IEC 27001 information security management standards.
Technologies: Visual Studio, JavaScript, ASP.NET, Agile, Windows Server, Subversion (SVN), Microsoft SQL Server, ASP.NET MVC, C#, .NET, Team Leadership

Scrum Master | Senior Developer

2008 - 2012
Creditinfo Lietuva (part of Creditinfo International GmbH)
  • Led a software development team of up to eight people.
  • Led web, Windows, and Android software development projects.
  • Gathered requirements and developed a credit risk management platform.
  • Implemented an application for issuing credit cards and consumer loans.
Technologies: Visual Studio, JavaScript, ASP.NET, Agile, Android, Mono, Windows Server, Subversion (SVN), Microsoft SQL Server, ASP.NET MVC, C#, .NET

Software Developer

2005 - 2008
Iterija
  • Analyzed and documented requirements.
  • Developed document management application.
  • Troubleshot and fixed various issues in the application.
  • Recruited and coached developers.
Technologies: Visual Studio, CSS, HTML, JavaScript, Microsoft SQL Server, C#, ASP.NET

Implemented Scalable, Resilient and Loosely Coupled Architecture with AWS SNS and SQS

https://medium.com/@arnoldasg/implementing-scalable-resilient-and-loosely-coupled-architecture-with-aws-sns-and-sqs-74bc9f651162
I developed an event-based architecture that replaced synchronous API calls with publishing AWS SNS notifications and using AWS SQS queues for processing them. This implementation improved the resilience and performance of the microservice-based platform. It was also capable of handling 4 million events per day with spikes of 500 events per second.

Technologies: AWS SNS, SQS, JMS, JustSaying

Improved Resilience in Distributed System with Polly

https://medium.com/@arnoldasg/resilience-in-distributed-systems-with-polly-f05b218a6485
I implemented a smart retry with a delay mechanism in RESTful API calls using the Polly library. It reduced errors from a few hundred to nearly a zero per hour in communication over the HTTP channel.

Technologies: C#, ASP.NET Web API 2, Polly

Improved API Performance

I worked on a performance improvement project in a distributed system. The goal was to meet the demand of the number of transactions per second from one important partner. I analyzed a number of API endpoints and did various performance improvements – from SQL query optimization to code refactoring. That gave profound results. For example, the response time of one of the most commonly used API endpoints was reduced from 30 milliseconds to 13 milliseconds and throughput increased from 50 to 150 transactions per second. After optimization, we were able to meet the performance requirements of our partner.

Technologies: Locust, Visual Studio

Migrated Applications from EC2 to ECS

I worked on migrating applications from hosting on EC2 instances (virtual machines) to ECS (Elastic Container Service). We added Docker support for Java Spring Boot applications. As we were using a bunch of .NET applications we also had to migrate from .NET Framework to .NET Core. I analyzed all libraries that we used and migrated them to .NET Standard. I also migrated Web API applications to ASP.NET Core 2.

Technologies: Docker, ECS, Jenkins, ASP.NET Core 2, Spring Boot

Hangfire.MySQLStorage – Open Source MySQL Storage Implementation of Hangfire

https://github.com/arnoldasgudas/Hangfire.MySqlStorage
I developed an open-source MySQL storage library for Hangfire – fire-and-forget, a delayed and recurring tasks runner for .NET and .NET Core, a scalable and reliable background job runner. It supports multiple servers, CPU, and I/O intensive, long-running and short-running jobs. The library has over 400 000 downloads on nuget.org.

Technologies: C#, MySQL, .NET, .NET Core, Xunit.

Implemented ISO/IEC 27001 Security Standards

I implemented ISO/IEC 27001 certification security standards in the credit bureau Creditinfo. It included the analysis of the security status, preparing new processes, documentation and fixing security issues in the application and infrastructure.
2006 - 2008

Master's Degree in Informatics Engineering

Vilnius Gediminas Technical University - Vilnius, Lithuania

2002 - 2006

Bachelor's Degree in Computer Science

Vilnius Gediminas Technical University - Vilnius, Lithuania

AUGUST 2020 - AUGUST 2022

Microsoft Azure Solutions Architect Expert

Microsoft

OCTOBER 2013 - PRESENT

Professional Scrum Master I

www.scrum.org

MARCH 2007 - PRESENT

Microsoft Certified Technology Specialist: SQL Server 2005

Microsoft

Languages

C#, Java, JavaScript, HTML, CSS, Gherkin, Python, Go

Frameworks

.NET, ASP.NET Core, Spring Boot, ASP.NET MVC, ASP.NET, Mono, IdentityServer 4, Locust, .NET Core, Entity Framework Core

Libraries/APIs

Web API 2, REST APIs, Azure Blob Storage API, React

Paradigms

Microservices Architecture, RESTful Development, Agile, Test-driven Development (TDD), Event-driven Architecture, CQRS, Event Sourcing, Management, Objectives & Key Results (OKRs)

Storage

Microsoft SQL Server, MySQL, Amazon DynamoDB, PostgreSQL, Redis, Redis Cache, Elasticsearch, Amazon S3 (AWS S3), Datadog

Tools

Azure Kubernetes Service (AKS), Git, Visual Studio, Amazon Simple Queue Service (SQS), Amazon Simple Notification Service (Amazon SNS), Azure Key Vault, Terraform, Kentico, Subversion (SVN), Helm, Bitbucket, Azure Application Insights, Amazon Cognito, Amazon CloudWatch, Docker Compose, Amazon EKS, CircleCI, Sumo Logic, Amazon CloudFront CDN, Jenkins, Jira, Grafana, MongoDB Atlas, GitLab

Platforms

Azure, Kubernetes, Amazon Web Services (AWS), Docker, Windows, Visual Studio Code (VS Code), Windows Server, Android, Linux, AWS Lambda, New Relic, PagerDuty, Apache Kafka, MacOS

Other

Azure Service Bus, Mambu, Team Leadership, Remote Team Leadership, Azure Container Registry, Domain-driven Design (DDD), Loggly, Amazon API Gateway, Platforms, Prometheus, cast.ai, Amazon RDS

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