Nicolas Milcoff, Developer in Rosario, Argentina
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Nicolas Milcoff

Verified Expert  in Engineering

Mobile Developer

Rosario, Argentina
Toptal Member Since
May 21, 2017

Nico is a mobile development expert, trainer, and international speaker. He is also a Microsoft MVP who actively contributes to/maintains open-source projects in the mobile space, like MvvmCross—he loves to push forward the technologies he works with. Nico is a team worker and feels motivated with all opportunities to share goals and interests with other people.


Mobile App Development, Team Leadership, Redux, TypeScript...
Xablu BV
Mobile App Development, Visual Studio Code (VS Code), Mobile Architecture...
Mobile App Development, Android, iOS, Git, C#, Xamarin.Forms, Xamarin...




Preferred Environment

TypeScript, Android, iOS, React Native, GitHub, Git, SourceTree, Android Studio, Xcode, Visual Studio Code (VS Code)

The most amazing...

...code I've written is part of an OSS framework I maintain, and it is used in thousands of mobile apps around the world.

Work Experience


2019 - PRESENT
  • Created an open-source library to easily consume REST and GraphQL APIs in C#.
  • Rearchitected two different mobile apps, which led to improved performance, increased developer productivity, and shorter time to market.
  • Created a unit testing infrastructure that is currently used in multiple production projects.
  • Oversaw and led multiple development teams in a remote-first setup.
  • Provided technical guidance to external customers and internal company projects.
  • Delivered more than ten technical talks at different meetups around the world.
Technologies: Mobile App Development, Team Leadership, Redux, TypeScript, Visual Studio Code (VS Code), Android, iOS, Git, C#, Xamarin.Forms, Xamarin, Android SDK, Visual Studio, Mobile Architecture, Java, Swift, Solidity, .NET Core, React Native

Mobile Development Trainer

2018 - PRESENT
Xablu BV
  • Facilitated on-site training about Xamarin development in New York (US), Mechelen (Belgium), and Almelo (The Netherlands).
  • Crafted and delivered a strategy training on mobile apps development, which compares React Native, Flutter, and Xamarin.
  • Trained and coached app development teams from companies such as UPS, Philips, and KPN.
  • Led virtual training on mobile development for a team in the Netherlands.
Technologies: Mobile App Development, Visual Studio Code (VS Code), Mobile Architecture, React Native, Git, Xamarin.Forms, Xamarin, Visual Studio, iOS, Android

Core Project Maintainer

2017 - PRESENT
  • Built a new set of ViewPresenters for each platform the framework supports.
  • Managed projects through issue resolution as part of my role.
  • Participated in the framework architecture design.
  • Presented the framework in conferences and public speeches.
  • Guided junior developers and made contributions to documentation.
Technologies: Mobile App Development, Android, iOS, Git, C#, Xamarin.Forms, Xamarin, Android SDK, Visual Studio

CEO | Lead Mobile Developer

2014 - 2019
  • Led a team of four developers with different seniorities involved in resource planning, coordination of tasks, and full responsibility for deadlines and objectives.
  • Developed cross-platform enterprise mobile apps in multiple lines of business, some with particular requirements (such as offline sync and background processing).
  • Developed cross-platform consumer mobile apps for investment groups. Participated in the concept and design of the apps as well.
  • Created a framework for Xamarin with a set of features, plugins, and abstraction for common functionalities.
  • Created binding libraries for Xamarin and contributed to several community maintained libraries.
  • Gave guidance and support to junior developers, making coding guidelines, slides, and exercises to help new developers get started.
  • Contributed to the functional analysis and design of UI/UX for mobile apps as part of the software development process.
Technologies: Mobile App Development, Team Leadership, Visual Studio Code (VS Code), Android, iOS, Git, C#, Xamarin.Forms, Xamarin, Android SDK, Visual Studio, Mobile Architecture, Firebase, Azure, .NET, MvvmCross, SQLite

Mobile Developer

2017 - 2018
Cortina Productions (via Toptal)
  • Built a native cross platform app for Android and iOS, to be used by thousand students.
  • Made Swift and Java libraries available to be used in Xamarin.
  • Built an offline sync engine that included downloading several videos in parallel, with optimized battery consumption.
Technologies: Mobile App Development, Android, iOS, Git, C#, Xamarin, Visual Studio, Java, Swift, Subversion (SVN)

Mobile Developer

2017 - 2017
TillPOS (via Toptal)
  • Created a native application for iOS, Android, and UWP.
  • Built an offline data synchronization engine in C#.
  • Built a printer infrastructure with ESC/POS for the existing mobile app.
  • Created a cross-platform navigation service that respects platform idioms.
  • Developed a responsive/flexible UI using custom renderers.
Technologies: Mobile App Development, Android, iOS, Git, C#, Xamarin.Forms, Xamarin, Visual Studio, MVVM Light Toolkit, SQLite

Mobile Developer

2014 - 2015
Clover Sistemas SRL
  • Developed a Xamarin-based cross-platform mobile app for a health insurance company that now has thousands of users.
  • Built a framework to make UI testing with Xamarin faster and more efficient.
  • Created a mobile app following TDD methodology as part of a group of developers. The app ended up having 80% test coverage.
  • Improved the speed and stability of a mobile app in maintenance (that I did not develop) by changing some of the core features of the app.
Technologies: Mobile App Development, Android, iOS, Git, C#, Xamarin.Forms, Xamarin, Visual Studio, Couchbase, MvvmCross

IT Intern

2013 - 2014
Laboratorio STEM
  • Made a functional analysis of the entire workflow of the company and documented the processes. Those documents are now used to introduce new members to the company.
  • Created information reports based on the needs of the users and what I considered important. With this information, the company increased sales by over 30%.
  • Gave end-users training and support while using the company's software.
  • Made presentations and a workshop to introduce end-users to SQL.
Technologies: C#, Visual Studio, Crystal Reports, .NET

Open Source Library: BreachDetector
A mobile, cross-platform library based on Swift/Java components that allow mobile apps to detect root, emulation, debug mode, and other security concerns at runtime. This library is available for Xamarin developers.

Open Source Framework: MvvmCross
I am a maintainer of MvvmCross, the popular MVVM framework for Xamarin.
MvvmCross allows developers to build clean, pixel perfect, native UIs while sharing behavior and business logic in a single codebase across all the supported platforms, using the Model-View-ViewModel (MVVM) design pattern.

Open Source Library: EasyTipView
This library is a C# port of an existing Swift library with the same name. It allows developers to easily place fully customizable tooltips in their app UIs. It is available for Xamarin.iOS developers.

Open Source Library: RootBeer (Xamarin)
A Xamarin binding library for RootBeer, the famous Android Java component that allows developers to detect device root conditions in runtime. It is distributed through NuGet and customized to be C#-friendly.

Open Source Library: IOSSecuritySuite (Xamarin)
A Xamarin binding library for the original IOSSecuritySuite library, an advanced and easy-to-use platform security and anti-tampering library written in pure Swift. This project contains all the annotations that make it C#-friendly.

SailConnect Mobile
SailConnect is a mobile app written in Xamarin using the traditional approach. The app is available on Android and iOS. Within the app, users can attend events, chat, and prepare together before the race starts.

iDriveYourCar Drivers Mobile App

A native mobile app developed with Xamarin and MvvmCross, available on iOS and Android platforms. This app is part of the business process of iDriveYourCar and supports the drivers' workflows. Within this app, drivers can manage their personal information, trips, and reviews. The app also supports all driver actions during a trip (call/chat with passengers or support, add expenses, and more).

Reveal Page Mobile
A native mobile app available for iOS and Android platforms. Developed with Xamarin and MvvmCross, it uses SQLite, Fody, and ReactEx. It is a comprehensive mobile social network that connects people following their interests and passions. Within the app, users can add other users to their relationships and have conversations with them. They can also publish posts, create their own sticker, and create albums of stickers.

AtlonXpense Mobile
A native mobile app for expense management developed with Xamarin and MvvmCross. Through this app, company workers can handle their expenses in a very effective and efficient way by taking full advantage of the multimedia capabilities today's smartphones bring. The application is available for iOS and Android platforms.

Billing App

A native mobile app for iPad developed using Xamarin and MvvmCross. This app allows the owner's clients to generate documents, offers, work orders, and invoices offline and sync them later in the office. Invoices and work orders can be signed by clients within the app, which allows a better and more efficient workflow experience.

MvvmCross: MvxIosViewPresenter
The code that is one of my contributions to the MvvmCross framework. The code is written in C#. It uses Xamarin/iOS tools, and of course, it is based on MvvmCross. It is a class responsible for handling how a view should be shown on an iOS app.

ClinicApp Mobile

A native mobile app developed with Xamarin technologies. It is available for the Android platform. This app allows users to generate medical appointments directly from their phones, having the possibility to choose a particular doctor, date, and time. Users can also manage relatives and create appointments for them.


A native mobile app for work and project planning inside companies. Through this app, users can manage their tasks and assignments, as well as exchange information with their coworkers. The application is available for iOS and Android platforms.

La Segunda NetVos

A native mobile app for the insurance group La Segunda made for the customers of the company. Within the app, users can view their insurance policy data, download official certificates, and check their policy expiration date. Users can also register any accidents they have, attach photos, and verify the closest agencies using maps. I've developed the Windows mobile application and also participated in the development of the Android version of the app.
2009 - 2017

Bachelor Degree in Software Engineering

Universidad Tecnológica Nacional - Rosario, Argentina

2014 - 2015

Exchange Semester (Via Universidad Tecnológica Nacional) in Software Engineering

Hochshule Esslingen - Esslingen, Germany


The Complete React Native + Hooks Course



Microsoft MVP


JULY 2016 - JULY 2017

Xamarin Certified Mobile Developer

Xamarin University


First Certificate in English

Cambridge English Language Assessment


Xamarin.Android, Xamarin.iOS, LINQ, SQLite.NET, MobX, Node.js, React


Visual Studio, SourceTree, Fody, Slack, TFS, Git, GitHub, Visual Studio App Center, G Suite, Xcode, Redux Toolkit, Firebase Cloud Messaging (FCM), Android Studio, Azure Mobile, Jira, Postman, Trello, Crystal Reports, Subversion (SVN), NPM


Windows Presentation Foundation (WPF), Android SDK, Xamarin.UITest, Newtonsoft JSON, .NET, React Native, MVVM Light Toolkit, Redux, .NET Core, YARN, AngularJS, ASP.NET MVC


C#, XML, XAML, Swift, TypeScript, GraphQL, JavaScript, YAML, Solidity, Java, SQL, HTML


Agile Software Development, Model View ViewModel (MVVM), REST, Agile, Mobile UI Design, Mobile UX Design, Mobile Design, Unit Testing, Scrum, Test-driven Development (TDD)


iOS, Android, Universal Windows Platform (UWP), Xamarin, MvvmCross, Visual Studio Code (VS Code), MacOS, Azure, Firebase


JSON, SQLite, Couchbase


Async/Await, Mobile Architecture, Leadership, Mobile Apps, Mobile App Development, Open Source, Xamarin.Mac, Technical Leadership, Team Leadership, Xamarin.Forms, Async.js, User Experience (UX), Axios, Documentation, Writing & Editing, Genetic Algorithms, Android Development, Algorithms, Integration Testing, HTTP, Enterprise Resource Planning (ERP)

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