Kumaran Vellaisamy, Developer in Almere, Netherlands
Kumaran is available for hire
Hire Kumaran

Kumaran Vellaisamy

Verified Expert  in Engineering

C# Developer

Almere, Netherlands
Toptal Member Since
July 16, 2021

Kumaran is a technology enthusiast and fast learner interested in understanding business and consumer problems and creating innovative solutions to solve them using technology and adding value. Kumaran has primarily worked as a senior developer and consultant, leading teams and building web and mobile applications.


142 Consulting SAS
JavaScript, RabbitMQ, PostgreSQL, React, Stripe Connect
Global Data Science Software Company
C#, Windows Forms (WinForms), Desktop, JavaScript, React, Windows, Unit Testing
Khosla Tech
ASP.NET Core, ASP.NET MVC, ASP.NET Web API, ServiceStack, AngularJS, JavaScript...




Preferred Environment

Visual Studio, Git, Azure DevOps, Bitbucket, GitLab, Azure, OneSignal, Kibana, Xamarin

The most amazing...

...thing I've done is modernize a complex WinForms desktop application across multiple sprints without having any impact on its other development processes.

Work Experience

Full-stack Developer

2022 - 2022
142 Consulting SAS
  • Implemented Stripe Connect to enable customers to receive payments via Stripe.
  • Did a high-level architecture, design, and code review of the existing codebase. Provided the necessary action to make the system more secure and manageable.
  • Analyzed new feature requirements and provided the plan with the estimates and required technical implementations on top of the features.
Technologies: JavaScript, RabbitMQ, PostgreSQL, React, Stripe Connect

Senior Desktop Software Engineer

2021 - 2022
Global Data Science Software Company
  • Worked on modernizing the WinForms desktop application UI.
  • Worked with the product manager and UX Designer to evaluate the design and identify the possible implementation approaches.
  • Worked with the product manager in estimation, identifying the deliverables for each sprint, and sprint planning.
Technologies: C#, Windows Forms (WinForms), Desktop, JavaScript, React, Windows, Unit Testing

Senior Full-stack Developer

2020 - 2022
Khosla Tech
  • Implemented the platform-specific ASPSecurityKit core libraries for all supported platforms. These libraries get the required data from the HTTP request for the request pipeline and process other commands related to authentication and authorization.
  • Designed and developed the source pack components for all supported platforms. Most of the components are developed in a shared code model, which reduced the time required to develop new features and maintenance overhead for all platforms.
  • Wrote documentation articles about ASPSecurityKit and created samples on how to build SaaS apps using ASPSecurityKit.
  • Created a tool to extract and inject C# code blocks from code files based on compiler directives and form a code definition file. These files are again used to inject the extracted code into code files.
  • Designed and developed a mechanism to load an angular app inside the Xamarin Android app using WebView to provide the ability to capture different data points as per the doctors’ needs.
  • Involved in the development of different components and features for the Gluco mobile application and Gluco Web API.
Technologies: ASP.NET Core, ASP.NET MVC, ASP.NET Web API, ServiceStack, AngularJS, JavaScript, jQuery, Xamarin.Android, SpecFlow, NUnit, Azure Functions, Azure App Service, Azure SQL, Azure Table Storage, Azure Blob Storage API, Azure Service Bus, Azure Application Insights, .NET Core, Azure Active Directory, Azure, Angular, Entity Framework Core, Entity Framework, REST APIs, ASP.NET, SQL, LINQ, Authorization, Authentication, Xamarin.Forms, C#, .NET, Windows, Xamarin, Unit Testing, Integration Testing

Security Developer

2017 - 2020
Forge Trust
  • Involved in implementing and improving authentication and authorization systems like HMAC based authentication, Azure Active Directory-based authentication, and role-based authorization to secure ISCP Web API.
  • Involved in the design and development of API for various security-related management activities like user management, permissions management, email throttling, IP management, etc.
  • Involved in the design and development of secured automated documentation of ISCP Web API. This resulted in having the API public documentation up to date without any manual work.
  • Involved in the development of an integrated validator approach combing field validation and business validations.
  • Involved in code reviews, module design discussion and reviews, and production monitoring of errors, security incidents, etc.
Technologies: C#, ServiceStack, Azure Active Directory, Kibana, NUnit, Shaolinq, Web API, JavaScript, AngularJS, Authentication, Authorization, Azure, Angular, REST APIs, SQL, LINQ, SpecFlow, ASP.NET Core, jQuery, Windows, Xamarin, Unit Testing, Integration Testing


2013 - 2016
  • Involved in the development of several services provided by CPF such as medical insurance claim calculator, provident fund withdrawal calculator, an administrative component of the medical insurance claim, and a few more.
  • Developed a generic validation mechanism for all input controls, which applied a generic error message format for each type of validation attribute.
  • Led a small team, ensuring the quality of deliverables as a responsibility.
  • Developed multiple PoCs to showcase the solution for the problems faced by customers as part of presales.
Technologies: ASP.NET MVC, Universal Windows Platform (UWP), Xamarin.Forms, JavaScript, jQuery, NUnit, TFS, XAML, Azure, REST APIs, ASP.NET, SQL, LINQ, ASP.NET Web API, C#, .NET, Windows, Unit Testing, Integration Testing

Application Developer

2010 - 2013
  • Involved in analyzing the possibility of migrating the application from WinForms to WPF.
  • Developed wrapper and custom controls as an equivalent of existing WinForms controls.
  • Developed a framework component called Layout Manager, which handles creating the layout using container controls such as StackPanel, Grid, TabControl, and arranging the application components based on the view configuration.
  • Developed a dashboard component called Tile Manager, which supports resizing, moving, expanding, and collapsing tiles. It also supported the import and export of the current state.
Technologies: C#, Windows Forms (WinForms), Windows Presentation Foundation (WPF), XAML, LINQ, .NET, Windows, Desktop


ASPSecurityKit is an enterprise-grade security framework with identity and access management components for multi-tenant ASP.NET framework, ASP.NET Core, and ServiceStack web applications. It protects the application with a comprehensive security pipeline built on a zero-trust model.

TB Reach Wave 6

A Xamarin Forms-based app to capture the process of referrals, testings, treatment, and outcomes of the TB symptomatic cases in a progressive manner from the TB Reach Wave 6 Project (RIPEND) implemented by TB Alert India (TBAI) with support from RB Reach Wave 6 grant (Stop TB Partnership) in the state of Telangana (INDIA)

Distomatic (Xamarin Forms App)

Distomatic is a distributor management system to automate your small, medium, and large-sized business. You can manage your end-to-end distribution operations like purchase, sales, inventory, billing, payments, daily issue/receive, returns, expenses, and accounting. It helps you to manage your business systematically and effectively to achieve high profits.

Kawris Ticketing Platform

Kawris is a conversational event ticketing platform. It makes the ticket purchase experience smoother via WhatsApp and Telegram bots. The ticket verification is also handled by WhatsApp and Telegram bots.
2006 - 2010

Bachelor's Degree in Information Technology

Anna University - Chennai, Tamilnadu, India


LINQ, REST APIs, Windows Forms (WinForms), jQuery, Web API, Azure Blob Storage API, Entity Framework, Xamarin.Android, React, Stripe Connect, Twilio API


Visual Studio, Git, Azure App Service, Azure Application Insights, Bitbucket, GitLab, Slack, Microsoft Teams, TFS, Kibana, Microsoft Flow, OneSignal, RabbitMQ


.NET, Windows Presentation Foundation (WPF), ASP.NET MVC, .NET Core, NUnit, ServiceStack, ASP.NET Core, ASP.NET Web API, ASP.NET, Entity Framework Core, AngularJS, SpecFlow, Angular, Jest


Unit Testing, Azure DevOps


C#, XAML, JavaScript, SQL, TypeScript


Universal Windows Platform (UWP), Azure Functions, Azure, Windows, Desktop, Xamarin, Amazon Web Services (AWS)


Azure SQL, Azure Cosmos DB, Azure Table Storage, Azure Active Directory, SQLite, PostgreSQL


Xamarin.Forms, Authentication, Authorization, Integration Testing, Shaolinq, Azure Service Bus, Bluetooth, Bots

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.


Share your needs

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

Choose your talent

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

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