Finding the right .NET development outsourcing company is rarely just about comparing rates or team sizes. Businesses often look for partners that can fit into existing workflows, understand long-term technical goals, and deliver software that remains maintainable as requirements change. Whether the project involves a new web platform, cloud migration, enterprise application, or ongoing product development, experience with the Microsoft ecosystem can make a noticeable difference.

This list includes .NET development outsourcing companies that work with organizations of different sizes, from startups building their first products to enterprises modernizing legacy systems. Some focus on dedicated development teams, while others provide full-cycle software engineering services that cover everything from planning and development to deployment and ongoing support. Each company brings a different mix of technical expertise, industry experience, and delivery approach, making it easier to find a team that aligns with specific business and project needs.

1. Oski Solutions

At Oski Solutions, a large part of our work involves .NET development, particularly for businesses that rely on stable, long-term platforms rather than short-lived projects. We develop web applications, business systems, cloud-based solutions, and custom software that become part of day-to-day operations. Many of the organizations we work with come from industries such as logistics, healthcare, fintech, education, and e-commerce, where software often needs to integrate with multiple systems and continue evolving over time.

Our team handles the full development lifecycle, from planning and architecture through deployment and ongoing support. Alongside .NET and C#, we work with technologies such as Azure, AWS, React, Angular, SQL Server, PostgreSQL, and Umbraco. In some projects, we join an existing internal team to provide additional engineering capacity, while in others we take responsibility for the entire delivery process.

Key Highlights:

• .NET and C# software development

• Experience with legacy system modernization

• Full-cycle software and web development

• Team augmentation and IT outsourcing services

• Cloud deployment using Azure and AWS

• Umbraco and WordPress development

Services:

• .NET development outsourcing

• C# development

• ASP.NET development

• Custom software development

• Web application development

• Umbraco development

• Cloud solutions

• Azure development

Contact Information:

• Website: oski.site

• E-mail: [email protected]

• LinkedIn: www.linkedin.com/company/oski-solutions

• Address: Kaupmehe tn 7, 10114 Tallinn, Estonia

• Phone: +48571282759

2. Inoxoft

Inoxoft works with companies that need external development support for building, updating, or maintaining software based on the .NET ecosystem. Their team covers a broad range of development activities, including web applications, mobile products, cloud systems, and business software. .NET is one of the technologies they use most frequently, and their engineers support everything from new application development to platform migrations and long-term maintenance.

Alongside software development outsourcing, Inoxoft provides dedicated teams and staff augmentation services for organizations that need to expand their technical capacity without building an in-house department from scratch. Their approach extends beyond coding alone, covering product discovery, design, testing, and technical audits when needed.

Key Highlights:

• Software development outsourcing

• Dedicated development teams

• IT staff augmentation

• Legacy system migration support

Services:

• ASP.NET web development

• Software development outsourcing

• Dedicated development teams

• IT staff augmentation

• API development and integration

• Custom .NET development

Contact Information:

• Website: inoxoft.com

• E-mail: [email protected]

• Facebook: www.facebook.com/inoxoft

• Twitter: x.com/InoXoft_Inc

• LinkedIn: www.linkedin.com/company/inoxoft

• Instagram: www.instagram.com/inoxoft_team

• Address: Heroiv UPA 72, Lviv, 7901, Ukraine

• Phone: (267) 310-2646

3. Blackthorn Vision

Blackthorn Vision focuses on custom .NET development for businesses that need software tailored to specific operational requirements rather than off-the-shelf solutions. Their work ranges from straightforward web applications to larger enterprise systems with multiple layers of functionality.

The company also supports organizations that need to modernize existing applications or move workloads into cloud environments. Besides core .NET development, Blackthorn Vision works with API integrations, e-commerce platforms, enterprise software, and mobile applications. Their service offering reflects the needs of companies looking for outsourced development resources while maintaining a consistent technology stack across web, cloud, and mobile products.

Key Highlights:

• Custom .NET software development

• Legacy software modernization

• Cloud migration support

• Enterprise software expertise

• API integration services

Services:

• Custom .NET development

• API development and integration

• Legacy system migration

• Software modernization

• Enterprise application development

• Cloud-native application development

• Cloud migration services

Contact Information:

• Website: blackthorn-vision.com

• E-mail: [email protected]

• Facebook: www.facebook.com/blackthornvision

• LinkedIn: www.linkedin.com/company/blackthorn-vision

• Instagram: www.instagram.com/blackthorn_vision

• Address: Twarda 18, 00-831 Warszawa, Poland

4. A-listware

A-listware work spans a wide range of technologies, including Microsoft .NET, and they support businesses that prefer flexible team structures. Much of their work is centered on integrating external developers into existing workflows while maintaining day-to-day collaboration with client teams.

Beyond development itself, A-listware offers consulting, infrastructure management, testing, cybersecurity, and application support services. They work with organizations across sectors such as finance, healthcare, retail, logistics, manufacturing, and telecommunications. .NET sits within a broader engineering environment that includes cloud platforms, data analytics, DevOps, and enterprise software development.

Key Highlights:

• Software development outsourcing

• Team augmentation services

• Dedicated development teams

• Microsoft .NET expertise

• Infrastructure and application support

• Cloud and enterprise software development

Services:

• .NET development

• Software development outsourcing

• Team augmentation

• Dedicated development teams

• Custom software development

• Enterprise software development

Contact Information:

• Website: a-listware.com

• E-mail: [email protected]

• Facebook: www.facebook.com/alistware

• LinkedIn: www.linkedin.com/company/a-listware

• Address: St. Leonards-On-Sea, TN37 7TA, UK

• Phone: +44 (0)142 439 01 40

5. N-iX

N-iX has been working with .NET technologies as part of its broader software engineering and digital transformation practice. Their teams handle the development of enterprise applications, web platforms, IoT solutions, and modernization initiatives built on the Microsoft ecosystem. Beyond new development, they also support organizations that need to improve existing .NET systems, extend functionality, or move applications from older technologies to more current environments.

A noticeable part of their work is focused on long-term engineering support rather than one-off development tasks. N-iX combines software design, implementation, maintenance, and migration services within the same delivery process, allowing companies to continue evolving their applications after launch.

Key Highlights:

• End-to-end .NET development

• Enterprise software engineering

• Cross-technology migration services

• IoT solution development

• Application modernization

• Ongoing system maintenance

Services:

• Enterprise application development

• Web application development

• IoT software development

• Digital transformation services

• .NET development

• Software modernization

Contact Information:

• Website: www.n-ix.com

• E-mail: [email protected]

• Facebook: www.facebook.com/N.iX.Company

• Twitter: x.com/N_iX_Global

• LinkedIn: www.linkedin.com/company/n-ix

• Address: London, EC3A 7BA, 6 Bevis Marks

• Phone: +442037407669

6. Scalo

Scalo approaches .NET development with a strong focus on backend systems, software modernization, and long-term maintainability. Their teams build applications that handle business logic, integrations, and large volumes of data while keeping future expansion in mind.

Scalo also supports migration, consulting, and team extension engagements. They work with cloud-native architectures, microservices, and Azure-based environments, helping organizations update existing software without disrupting day-to-day operations. The company also develops desktop, mobile, and low-code solutions within the .NET ecosystem.

Key Highlights:

• Cloud-native development expertise

• Microservices architecture experience

• Legacy software modernization

• Azure-based development

• Consulting and team extension services

Services:

• Custom .NET development

• ASP.NET web applications

• Backend system development

• Cloud-native applications

• Software migration

• Legacy software support

• Cloud migration services

• Product integrations

Contact Information:

• Website: www.scalosoft.com

• E-mail: [email protected]

• Facebook: www.facebook.com/scalosoft

• LinkedIn: www.linkedin.com/company/scalosoft

• Instagram: www.instagram.com/scalosoft

• Address: ul. Powstańców Śląskich 9, 53-332 Wrocław, Poland

• Phone: +48 665 594 665

7. SoftPro

SoftPro provides custom software development with .NET technologies forming an important part of its backend development offering. Their team works across both frontend and backend layers, combining Microsoft technologies with cloud platforms and modern web frameworks.

Their development process follows an agile structure with regular collaboration throughout the project lifecycle. Alongside custom applications, SoftPro develops cloud-based systems, enterprise software, and business platforms that integrate with existing workflows. The company also works with technologies such as ASP.NET, .NET Core, Azure, and AWS, supporting organizations that need scalable software and ongoing technical support.

Key Highlights:

• Custom software development

• .NET and ASP.NET expertise

• Full-stack development capabilities

• Agile development approach

Services:

• .NET development

• ASP.NET development

• Custom software development

• Full-stack development

• Web application development

• Cloud development

• Enterprise software development

Contact Information:

• Website: soft-pro.pl

• LinkedIn: www.linkedin.com/in/kyrylo-o

• Address: Mazowieckie Voivodeship, 13 Erasmus Ciołka St. 401, Warsaw, Poland

• Phone: +48 571 282 759

8. Sigma Software

Sigma Software works on software modernization, digital product development, cloud transformation, and AI-related initiatives. Their engineering teams help organizations move from planning stages to working software, with a focus on integrating systems, improving operations, and reducing technical complexity.

Sigma Software supports data engineering, cloud infrastructure, cybersecurity, embedded software, and IoT solutions. The company is also involved in AI adoption projects, helping organizations introduce automation and AI-driven capabilities into development processes, operations, and customer-facing products.

Key Highlights:

• Software modernization services

• Digital product development

• AI-powered software engineering

• Cloud migration and infrastructure support

• Data engineering expertise

• Cybersecurity integration

Services:

• Custom software development

• Digital product engineering

• Application modernization

• Cloud migration

• Data engineering

• AI integration

Contact Information:

• Website: sigma.software

• E-mail: [email protected]

• Facebook: www.facebook.com/SIGMASOFTWAREGROUP

• LinkedIn: www.linkedin.com/company/sigma-software-group

• Instagram: www.instagram.com/sigma_software

• Address: Wadowicka 7, 30-347 Krakow, Poland

• Phone: +38 (066) 882–0783

9. Lengreo

Lengreo combines software development services with a broader focus on digital growth and business support. It also provides .NET application development for businesses that need custom web solutions as part of their wider digital strategy. Their work is built around close collaboration and adapting development efforts to fit the specific goals of each client.

A practical aspect of Lengreo's approach is the emphasis on communication and integration with internal teams. Rather than treating software development as a separate activity, they connect development work with business processes, online presence, and customer acquisition efforts. This combination makes their .NET services part of a larger ecosystem that includes both technical and commercial objectives.

Key Highlights:

• .NET application development

• Close collaboration with client teams

• Flexible communication approach

• Combined technical and marketing expertise

Services:

• .NET application development

• Website development

• B2B digital marketing

• Lead generation

• SEO

• Content marketing

• Paid advertising management

• Demand generation

Contact Information:

• Website: lengreo.com

• E-mail: [email protected]

• Twitter: x.com/Lengreo

• LinkedIn: www.linkedin.com/company/lengreo

• Instagram: www.instagram.com/lengreo.agency

• Address: Vrijstraat 9 C/D, 5611 AT Eindhoven, Netherlands

• Phone: +31 686 147 566

10. Innowise

For Innowise, .NET development sits within a larger software engineering practice that covers application development, modernization, consulting, and technical audits. Their teams build web, desktop, mobile, and cloud-based applications using Microsoft technologies, while also helping organizations update existing software and move older systems to newer frameworks.

Alongside application development, Innowise works with tools such as SharePoint, Power BI, Microsoft Teams integrations, and Microsoft 365 customization. Their .NET offering extends from consulting and architecture planning through implementation, migration, testing, and ongoing support.

Key Highlights:

• Custom .NET software development

• Application modernization services

• ASP.NET Core expertise

• Microsoft technology ecosystem experience

• Software audit and consulting services

• Team augmentation options

Services:

• Custom .NET development

• .NET consulting

• Software audit

• ASP.NET Core development

• Blazor development

• Xamarin development

• Application modernization

• Migration to ASP.NET Core

Contact Information:

• Website: innowise.com

• E-mail: [email protected]

• Twitter: x.com/innowisegroup

• LinkedIn: www.linkedin.com/company/innowise-group

• Address: Pescara 66023, Via N. Adriatica Nord 58, Francavilla al Mare, Italy

• Phone: +48 787 027 706

11. 21century.tech

21century.tech takes a different approach to software development by combining senior engineering oversight with AI-assisted workflows. Rather than treating AI as a separate service, it is integrated into their day-to-day development process for code generation, testing, documentation, and refactoring. The company focuses on delivering working software quickly while keeping technical decisions, quality control, and accountability in the hands of experienced engineers.

For businesses looking to outsource .NET development, this approach can be useful when speed and iteration matter. 21century.tech handles application development, integrations, system improvements, deployment processes, and technical documentation while maintaining a strong emphasis on human review throughout the development cycle.

Key Highlights:

• AI-assisted software development workflow

• Senior engineer oversight

• Human-reviewed code delivery

• Rapid product iteration

• CI/CD implementation

Services:

• .NET development

• Custom software development

• Application refactoring

• Third-party integrations

• MVP development

• CI/CD setup

• Software testing

Contact Information:

• Website: 21century.tech

• E-mail: [email protected]

12. Belitsoft

Belitsoft centers much of its .NET outsourcing offering around backend systems, cloud applications, and enterprise software. The company works across the Microsoft ecosystem, combining .NET development with Azure services, database technologies, API integrations, and frontend frameworks when full-stack delivery is required.

A notable part of Belitsoft's work involves helping organizations modernize software environments without rebuilding everything from scratch. They handle migrations, cloud adoption, performance optimization, testing, and support. The company also works with technologies such as ASP.NET Core, .NET MAUI, React, Angular, Docker, Kubernetes, and Azure-based services.

Key Highlights:

• Full-cycle .NET development

• Azure cloud expertise

• Application modernization services

• API and system integration

• Full-stack development capabilities

Services:

• .NET development

• ASP.NET Core development

• Azure development

• Full-stack development

• API development and integration

• Cloud migration

• Application modernization

• Database development

Contact Information:

• Website: belitsoft.com

• E-mail: [email protected]

• Facebook: www.facebook.com/Belitsoft

• Twitter: x.com/BelitsoftCom

• LinkedIn: www.linkedin.com/company/belitsoft-llc

• Address: 26/28 Hammersmith Grove, London W6 7HA

• Phone: +44 (20) 3318-18-53

13. Itransition

Itransition provides .NET outsourcing services through several engagement models, including dedicated teams, team augmentation, and full-project delivery. Their .NET specialists work on web, mobile, desktop, cloud, and IoT applications, covering both customer-facing software and internal business systems.

Beyond application development, Itransition places considerable attention on software maintenance, modernization, and integration. Their teams work with ASP.NET Core, Blazor, .NET MAUI, Azure services, and a range of cloud and DevOps technologies.

Key Highlights:

• Dedicated .NET development teams

• Team augmentation services

• Full-project outsourcing

• Cloud and SaaS expertise

• Software modernization support

Services:

• Web application development

• Mobile application development

• Desktop application development

• .NET development

• IoT development

• Microservices development

• SaaS development

Contact Information:

• Website: www.itransition.com

• E-mail: [email protected]

• Facebook: www.facebook.com/Itransition

• Twitter: x.com/itransition

• LinkedIn: www.linkedin.com/company/itransition

• Address: 160 Clairemont Ave, Suite 200, Decatur, GA 30030

• Phone: +1 720 207 2820

14. Gilzor

Gilzor services cover the entire path from idea validation and business analysis through development, testing, and ongoing maintenance. Alongside software engineering, the company also helps clients evaluate product ideas, refine requirements, and prepare products for market launch.

A distinctive part of Gilzor's offering is the combination of development and product-focused services under one roof. While .NET outsourcing may be part of a broader technology strategy, their teams also contribute to UI/UX design, quality assurance, research activities, and product growth initiatives. The company develops both web and mobile applications while supporting long-term product evolution after release.

Key Highlights:

• Custom software development

• Product idea validation

• Business analysis services

• UI/UX design support

• Research and development capabilities

Services:

• Web development

• Mobile development

• .NET development

• Custom software development

• Business analysis

• Quality assurance

Contact Information:

• Website: www.gilzor.com

• E-mail: [email protected]

• LinkedIn: www.linkedin.com/company/gilzor-softwaredevelopment

• Address: Poland, Warsaw, Office 58, street Adama Mickiewicza 37, 01-625

15. Andersen

Andersen provides .NET outsourcing services as part of a wider software engineering practice that covers enterprise applications, cloud systems, web platforms, and digital transformation initiatives. Their .NET teams work with both distributed and monolithic architectures, supporting businesses that need custom software, platform upgrades, integrations, or additional development capacity.

Andersen combines .NET expertise with architecture design, business analysis, quality assurance, DevOps, and consulting services. The company also develops solutions based on ASP.NET and works with technologies commonly used in enterprise environments.

Key Highlights:

• Custom .NET development

• Enterprise application expertise

• System integration support

• Migration and modernization services

Services:

• .NET development

• ASP.NET development

• Custom software development

• Enterprise application development

• System integration

• Software migration

• IT consulting

Contact Information:

• Website: andersenlab.com

• E-mail: [email protected]

• Facebook: www.facebook.com/AndersenSoftwareDev

• Twitter: x.com/AndersenLabs

• LinkedIn: www.linkedin.com/company/andersen-lab

• Instagram: www.instagram.com/andersen.global

• Address: 18 B3 Pokoju Ave., Kraków, 31-564, Poland

• Phone: +48 22 390 64 08

16. Net Devs

Net Devs focuses on enterprise software development with a delivery model that combines senior engineering oversight and AI-assisted execution. Their teams use AI tools to support development, testing, and documentation tasks, while architecture decisions, technical reviews, and quality control remain under the supervision of experienced engineers. .NET is one of several technologies they work with when building business applications and backend systems.

Net Devs supports cloud-native development across different platforms and environments. The company also handles discovery, architecture planning, deployment, and continuous improvements, keeping development, testing, and operational processes closely connected throughout the software lifecycle.

Key Highlights:

• Senior-led engineering teams

• AI-assisted development workflows

• Cloud-native architecture expertise

Services:

• Enterprise software development

• Cloud development

• Platform engineering

• .NET development

• AI engineering

• Frontend development

Contact Information:

• Website: net-devs.com

• E-mail: [email protected]

• LinkedIn: www.linkedin.com/company/net-devs

• Address: Obrzeżna 1D, 02-691 Warszawa, Poland

• Phone: +48 571 282 759

17. Nascenia

Nascenia provides .NET outsourcing services for companies that need external development support, software integration, cloud-based applications, or long-term maintenance. Their work covers both web and desktop applications, with additional focus on API connectivity and platform compatibility across different systems.

Alongside development, Nascenia offers consulting services to help businesses define technical requirements, timelines, and implementation approaches before a project begins. The company also maintains dedicated quality assurance, cybersecurity, and application development practices, allowing teams to support software throughout its lifecycle rather than only during the initial build phase.

Key Highlights:

• Software integration expertise

• Cloud application development

• API integration capabilities

• .NET consulting services

Services:

• Web application development

• Desktop application development

• .NET development

• Cloud development

• Technical consulting

• Quality assurance

Contact Information:

• Website: nascenia.com

• E-mail: [email protected]

• Facebook: www.facebook.com/nascenia

• Twitter: x.com/nasceniaIT

• LinkedIn: www.linkedin.com/company/nascenia-it

• Address: Mirza Hafiz House 23, Rapa Drive, Tarneit, Victoria 3029

• Phone: +61 451 459 259

18. Mobian

Mobian develops .NET applications for businesses that need custom software, web platforms, or cloud-based systems. Their approach combines .NET technologies with Azure services, focusing on secure and scalable applications that can adapt as requirements change over time.

Quality control is a visible part of Mobian's development process, with automated testing and code reviews integrated into delivery workflows. The company also contributes to the broader .NET community through open-source projects, which sets it apart from firms that focus only on client work.

Key Highlights:

• ASP.NET and .NET Core expertise

• Azure-based development

• Automated testing practices

• Open-source contributions

• Cloud platform experience

Services:

• Custom software development

• Web application development

• Cloud solutions

• Azure development

• .NET development

• Mobile application development

• Quality assurance

Contact information:

• Website: mobian.studio

• Email: [email protected]

• LinkedIn: www.linkedin.com/company/mobian-studio

• Address: Harju maakond, Tallinn, Kesklinna Linnaosa, Masina tn 22, 10113

19. ScienceSoft

ScienceSoft offers .NET outsourcing through several engagement models, ranging from full-project delivery to dedicated development teams and individual specialists. Their services extend beyond coding and include software planning, audits, cloud optimization, modernization, support, and developer training.

A notable aspect of ScienceSoft's .NET practice is the breadth of technologies and architectures they work with, including microservices, serverless environments, cloud-native applications, IoT systems, and SaaS platforms. The company also places considerable emphasis on project governance, with structured processes around documentation, reporting, change management, and knowledge sharing.

Key Highlights:

• Full-cycle .NET outsourcing

• Software modernization services

• Cloud migration expertise

• Application audit and review

• Developer training programs

• Structured project governance

Services:

• .NET development

• Software modernization

• Cloud migration

• Application maintenance

• Software audits

• Technical consulting

• DevOps services

Contact Information:

• Website: www.scnsoft.com

• E-mail: [email protected]

• Facebook: www.facebook.com/sciencesoft.solutions

• Twitter: x.com/ScienceSoft

• LinkedIn: www.linkedin.com/company/sciencesoft

• Address: 5900 S. Lake Forest Drive Suite 300, McKinney, Dallas area, TX 75070

• Phone: +1 214 306 6837

20. DevsData

DevsData works with companies that need software development, engineering support, and technical recruitment. Their .NET practice covers both enterprise systems and new product development, with teams involved in everything from application architecture to deployment and ongoing improvements. The company combines software engineering with expertise in cloud infrastructure, mobile applications, data science, and machine learning.

In addition to its internal engineering team, the company maintains a large network of vetted specialists and follows a structured screening process when assembling project teams. DevsData also emphasizes close collaboration with clients, using frequent feedback and iterative development to keep projects aligned with business goals.

Key Highlights:

• .NET development expertise

• Enterprise software development

• Technical recruitment services

• Cloud and DevOps capabilities

• Data science and AI experience

Services:

• Custom software development

• Enterprise application development

• Mobile app development

• Cloud infrastructure services

• .NET development

• AI and machine learning solutions

Contact Information:

• Website: devsdata.com

• E-mail: [email protected]

• Facebook: www.facebook.com/DevsData

• Twitter: x.com/devsdata

• LinkedIn: www.linkedin.com/company/devsdata/about

• Address: Al. Jerozolimskie 181B, 5th Floor, 02-222, Warsaw, Poland

Conclusion

Choosing a .NET development outsourcing company is not only about technical expertise. The way a team communicates, adapts to changing requirements, and fits into your workflow often has just as much influence on the success of a project. Some companies focus on dedicated development teams, others specialize in cloud migration, enterprise software, modernization, or long-term support. The best choice depends on what you need today and how you expect your software to evolve in the future.

The companies featured in this list offer a wide range of .NET services and outsourcing models, giving businesses plenty of options to explore. Taking the time to compare their strengths, delivery approaches, and areas of specialization can make the selection process much easier. Whether you are building a new application, expanding an existing platform, or looking for additional engineering capacity, the right outsourcing partner can help move the project forward while allowing your internal team to stay focused on core business priorities.