Top 20 C# Developers in Seattle
The Best of December 2025Looking for a top C Sharp software development company in Seattle?
The programming language C Sharp (C#), is general-purpose and used for web and mobile apps. It has a number of advantages: It's object-oriented, has automatic garbage collection, functions across platforms, has backward compatibility, and integrates well with other platforms and services.
To assist you in your search for a partner, we’ve compiled this list of the top C# developers in Seattle. Browse descriptions, feedback, and awards to find which can best suit your company’s needs.
List of the Best Seattle C Sharp (C#) Software Development Companies
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1$10,000+250 - 999 employeesBellevue, WARead More
Affirma Consulting is a custom software development firm established in 2001. Their midsize team is in Bellevue, Washington; Ahmedabad, India; Dublin, Ireland and Fayetteville, Arkansas. The firm focuses on Custom Software Development, AI Consulting, Generative AI, Mobile App Development, and more.
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MicrosoftIndustries
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2$50,000+10 - 49 employeesSeattle, WAATOMICUS, a custom software development firm, was launched in 1999. They are in Seattle, Washington and Gdańsk, Poland and have a small team. Their services include custom software development.Read More
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BRUKER CAMECA AMETEK Hitachi High-TechIndustries
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3$5,000+250 - 999 employeesKirkland, WAEstablished in 2005, UKAD is an IT staff augmentation company. Their midsize team is located in Kirkland, Washington; Kraków, Poland; Kharkiv, Ukraine and Cesson-Sévigné, France and focuses on IT staff augmentation, E-Commerce Development, Low/No Code Development, Custom Software Development, and more.Read More
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AJ Produkter Ginza TargetAid EntitledToIndustries
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4$5,000+10 - 49 employeesStockholm, SwedenRead More
Slashdev is a small custom software development firm based in Winter Park, Florida; London, England; Stockholm, Sweden and San Diego, California. They specialize in Custom Software Development, Web Development, Mobile App Development, IT staff augmentation, and more and were founded in 2020.
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5$25,000+2 - 9 employeesSeattle, WARead More
Lunarbyte.io is a development agency based in Seattle. Since 2019, the 3-person team has built websites, custom software, and mobile apps for predominantly small businesses.
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DDM ImportsIndustries
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6$10,000+50 - 249 employeesKirkland, WARead More
Founded in 2013, AccelOne is an artificial intelligence firm. They are headquartered in Kirkland, Washington; Buenos Aires, Argentina and Mission Viejo, California and have a midsize team. The firm offers Artificial Intelligence, Generative AI, IT managed services, IT staff augmentation, and more.
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XapoIndustries
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7$10,000+50 - 249 employeesBellevue, WARead More
Virtuosity Consulting, a custom software development firm, was launched in 2008. They are located in Bellevue, Washington and Navi Mumbai, India and have a midsize team. Their services include custom software development, IT managed services, enterprise app modernization, web development, and more.
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8Undisclosed50 - 249 employeesSeattle, WANTSprint LLC is a software development company. They are located in Seattle, Washington and have midsize team of experts. Their services include Custom Software Development and Web Development.Read More
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9$10,000+50 - 249 employeesSeattle, WADevblock is a software development company. Based in Seattle, Washington and Ho Chi Minh, Vietnam, the company offers Custom Software Development and Web Development.Read More
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10$10,000+10 - 49 employeesSeattle, WAPalador is a small custom software development firm headquartered in Seattle, Washington and Yogyakarta, Indonesia. Their services include Custom Software Development and Enterprise App Modernization.Read More
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11$10,000+50 - 249 employeesChicago, ILDMC, Inc., a custom software development firm, is based in Chicago, Illinois and Somerville, Massachusetts. The team provides Custom Software Development and CRM consulting and SI.Read More
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3MIndustries
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12$75,000+50 - 249 employeesSeattle, WATangoTeams, a midsize website development company, is in Seattle, Washington. Their services include Web Development and Mobile App Development.Read More
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13$50,000+50 - 249 employeesWoodinville, WAEstablished in 1996, Redapt is a cloud consulting & SI company. The agency focuses on cloud consulting & SI and BI & big data consulting & SI, and is midsize.Read More
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14$10,000+250 - 999 employeesBellevue, WAConfiz, an IT staff augmentation company, is in Bellevue, Washington and Dubai, United Arab Emirates. Launched in 2005, the team offers IT staff augmentation and ERP consulting and SI.Read More
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15$10,000+10 - 49 employeesSeattle, WAAmberteq is a small Enterprise App Modernization company. Founded in 2018, the team offers Enterprise App Modernization and cloud consulting & SI.Read More
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16Undisclosed10 - 49 employeesKirkland, WAJetstream Software, Inc., a software development company, provides Custom Software Development and AR/VR development. The agency is located in Kirkland, Washington.Read More
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17$1,000+10 - 49 employeesKent, WAEstablished in 2021, DigiCorders is a social media marketing firm. The team provides Social Media Marketing and Content Marketing.Read More
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18Undisclosed10 - 49 employeesSeattle, WALaunched in 2017, Diatomic Product Development is a Product Design company. The company focuses on Product Design and Custom Software Development.Read More
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19Undisclosed10 - 49 employeesSeattle, WACloud consulting & SI company Marici Technology Solutions provides cloud consulting & SI and ECM consulting and SI. They are headquartered in Seattle, Washington.Read More
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20Undisclosed10 - 49 employeesGig Harbor, WAAtaira Analytics Inc. Is a small big data company launched in 2015. Their team provides BI & big data consulting & SI and cloud consulting & SI.Read More
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21Undisclosed10 - 49 employeesFederal Way, WAKarma Consulting, Inc. Is an UX design agency. They are in Federal Way, Washington. Their team provides UX/UI Design and cloud consulting & SI.Read More
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22UndisclosedFreelancer employeesEverett, WAMystic Engineering / Mystic Industries is a small Product Design company located in Everett, Washington. Their services include Product Design and Custom Software Development.Read More
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23$10,000+250 - 999 employeesBellevue, WASOUTHWORKS is a midsize custom software development firm. They offer Custom Software Development and cloud consulting & SI and were launched in 2004.Read More
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