Best C# Developers in the United States

11 Companies-Rankings updated: September 03, 2026

Every agency on DesignRush meets evaluation criteria around expertise and client feedback to empower informed choices. Some listings include paid partnerships.

United States × C# Development × Construction × $25,000 - $50,000 ×Clear Filters
  • Diffco

    VerifiedVerified by the DesignRush team for authenticity and credibility.

    Your trusted AI software development partner

    Diffco is a software development company that builds cross-platform mobile apps, bespoke SaaS portals, custom database architectures, and admin management panels. The studio deploys clean Python, Node.js, React, and Swift codebases alongside automated testing setups and CI/CD pipelines engineered for...

    Top Services:

    • AI Development
    • Software Development
    • Staff Augmentation
    • Mobile App Development
    • Web Development
    • Show more
    Location
    San Jose, California
    Number of Employees
    50 - 99
    Average Hourly Rate
    $110/hr
    Minimal Budget
    $25,000 - $50,000
    Portfolios Count
    31 Projects Listed

    Diffco Services

    • AI Development
    • Software Development
    • Staff Augmentation
    • Mobile App Development
    • Web Development
    • eCommerce Development
    • IoT
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • Mars
    • Food Rocket
    • FlashGrid
    • Nokia
    • Instreamatic
    • Quire
    • Legionfarm
    • Latoken
    • Genius One
    • Shift
    Data sourced from the agency's DesignRush profile

    Diffco Reviews & Testimonials

    • Oleg Sotnikov
      Oleg Sotnikov CEO at AppMaster
      5.0

      AI Development Review from Oleg Sotnikov

      Diffco built a complex, production-grade AI agentic system and backend for our client's fintech platform owning architecture, AI/ML components, and AI agents in a security- and compliance-sensitive environment. They delivered on time and within budget, communicated proactively, and operated like part of our own team, taking ownership and suggesting better solutions throughout. Deep AI/ML and senior backend expertise. We'd happily work with them again.

    • Julia Platova
      Julia Platova VP Strategic Partnerships at OVA Solutions
      5.0

      Mobile App Development Review from Julia Platova

      We partnered with Diffco for a comprehensive software development project aimed at delivering a mobile application and backend system for our client. The goal was to create a seamless, secure, and scalable solution within a 4-month timeline and $50k-$200k budget.Diffcos team was highly professional from start to finish. They handled everything: UI/UX design, backend architecture, API integration, and deployment.After the launch, they continued to support us with maintenance and performance optimization.The application received positive feedback and has proven stable and scalable.Were highly satisfied with Diffcos expertise, commitment, and ability to deliver real results.

    • Max Shmatkov
      Max Shmatkov Manager at Centerligh
      5.0

      Mobile App Development Review from Max Shmatkov

      As an advantage of working with this company I’d like to note that their Agile development method is amazing! Diffco earned my trust through such approach and the team’s professional attitude.

    Reviews verified by DesignRush and sourced from the agency's profile View All Reviews
  • Trusted IT Partner for SMBs & Enterprises Since 2001 | Dedicated Teams | Industry-Specific Solutions

    Altoros is a 350+ person strong IT consulting and development group. For over 20 years, we've been assisting Global 2000 organizations in getting software products to market faster and reducing the cost of R&D experiments to enable stable business growth...

    Top Services:

    • Software Development
    • Mobile App Development
    • Web Design
    • Web Development
    • Staff Augmentation
    • Show more
    Location
    Pleasanton, California
    Number of Employees
    250 - 499
    Average Hourly Rate
    $50/hr
    Minimal Budget
    $25,000 - $50,000
    Portfolios Count
    12 Projects Listed

    Altoros Labs Services

    • Software Development
    • Mobile App Development
    • Web Design
    • Web Development
    • Staff Augmentation
    • Software Testing
    • AI Development
    • IoT
    • Cloud Consulting
    • Big Data Analytics
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • Siemens
    • Toyota
    • Hitachi
    • Huawei
    • Denso
    • LikeFolio
    • Dealflo
    • iFit
    • Walmart
    • EQ Bank
    Data sourced from the agency's DesignRush profile

    Altoros Labs Reviews & Testimonials

    • Daria Stolyar
      Daria Stolyar Manager at Custom Software Development Company
      5.0

      Software Development Review from Daria Stolyar

      We hired Altoros engineers as an essential extension of our client-facing internal teams. This was a tough decision because our reputation as a brand depends on the overall efficiency of our processes and we needed to make sure all risks are mitigated when it comes to delivery. Altoros has not let us down.Together with Altorosians we successfully deployed a number of tough and technologically complex projects on time. So our collaboration is certainly set to continue.

    • Victoria Lewis
      Victoria Lewis Director at Equine Affairs Ltd
      3.5

      Software Development Review from Victoria Lewis

      We enjoy working with our team, Roman Yurkin, Tatyana Kobzar, Svetlana Kalchanka and Tatiana Anop. They bring expertise and immense value to our business with each piece of work they complete. They are a major part of our business development and delivery.

    • Greg Lipper
      Greg Lipper Managing Director at Happi Pte Ltd
      5.0

      Ruby on Rails Review from Greg Lipper

      In my 30 years in the software business, I have never had as positive an experience with an outsourced development services provider as I have with Altoros. Each Altoros engineer we have worked with has been strong technically, estimated development times accurately, completed projects on time, and delivered code and projects with high quality. Beyond that, they have helped improve our thinking and approach with suggestions and ideas that were better than the spec of instructions we supplied.

    Reviews verified by DesignRush and sourced from the agency's profile View All Reviews
  • Engineering for live products where mistakes are expensive.

    KITRUM is an engineering partner focused on building on top of live software products. We help them grow beyond their original design by modernizing architecture, adding new capabilities, and scaling systems without disrupting what already works...

    Top Services:

    • Software Development
    • Mobile App Development
    • Web Development
    • IT Services
    • AI Development
    • Show more
    Location
    Miami, Florida
    Number of Employees
    100 - 249
    Average Hourly Rate
    $50/hr
    Minimal Budget
    $25,000 - $50,000
    Portfolios Count
    11 Projects Listed

    KitRUM Services

    • Software Development
    • Mobile App Development
    • Web Development
    • IT Services
    • AI Development
    • Software Testing
    • Staff Augmentation
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • Mastercard
    • Airbnb
    • Ebay
    • Lulalend
    • PawSquad
    • FreightCenter
    • Turf Tank
    • StackSource
    • Proteus Motion
    • Ledgerset
    Data sourced from the agency's DesignRush profile

    KitRUM Reviews & Testimonials

    • Daniel Rondell
      Daniel Rondell CTO at Fintech Industry
      5.0

      Software Development Review from Daniel Rondell

      We are notably satisfied with the upshot. PMs and development team was very devoted to the tasks and encouraging. We had a stringent and fixed deadline. And we got it just in time! KitRUM helped us to create an entire software that absolutely meets our requirement. They had presented the system in a short-term after putting their hands on it. They also provide support after developing this software. We have a different project now and certainly will work with KitRUM again.

    • Adelina Romanova
      Adelina Romanova Manager at GR Business Networking / Groupe Reso International Corp.
      5.0

      Software Development Review from Adelina Romanova

      KitRUM expanded our team to shift software to a new platform. Using JavaScript and RESTful APIs, they improved interfaces and DevOps, and fixed bugs. The team has always been on time. Their ability to understand the business requirements and their communication was just perfect. I definitely will recommend KitRUM as a reliable partner.

    • Daisy Skot
      Daisy Skot Client Manager at Nicholas Financial Inc.
      5.0

      Software Development Review from Daisy Skot

      KitRUM made a variety of development services: conception, coding, and QA, which means almost a full software package for our company. We needed to develop a few tasks, for example, a desktop app for our store, a cloud app for administration and supervision, and a portable app for end customers. However, we had an in-house team, which is not enough for this project. So we had to find a dedicated team that could deliver all we needed. We found KitRUM as a top-notch software development company

    Reviews verified by DesignRush and sourced from the agency's profile View All Reviews
  • Leading Edge. Lasting Impact.

    Troy Web Consulting is a trusted guide for organizations, delivering high-quality, practical software solutionscustom web apps, mobile apps, and websiteson time and on budget. We specialize in solving business challenges through custom tailored software development...

    Top Services:

    • Software Development
    • Mobile App Development
    • eCommerce Development
    • AI Development
    • Software Testing
    • Show more
    Location
    Cohoes, New York
    Number of Employees
    Under 49
    Average Hourly Rate
    $155/hr
    Minimal Budget
    $25,000 - $50,000
    Portfolios Count
    27 Projects Listed

    Troy Web Consulting Services

    • Software Development
    • Mobile App Development
    • eCommerce Development
    • AI Development
    • Software Testing
    • Web Development
    • WordPress Website Design
    • Web Design
    • UI/UX Design
    • Design Services
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • Advantedge Education
    • Center for Internet Security
    • Davis Vision
    • MyEssentials
    • Etransmedia
    • FortOrangePress
    • GroundWater Protection Council
    • LeadingAge
    • NYSERDA
    • The Enneagram Institute
    Data sourced from the agency's DesignRush profile

    Troy Web Consulting Reviews & Testimonials

    • Mei Huang
      Mei Huang Review from Google
      5.0

      Mei Huang's Review Sourced from Google

      I had a fantastic experience working at Troy Web Consulting. The team is incredibly supportive and welcoming. I worked on real client projects that helped me grow my technical skills and confidence. The culture is awesome, flexible, collaborative, and fun. You truly feel like part of the team from day one. Highly recommend.

    • Stephen Higgins
      Stephen Higgins Review from Google
      5.0

      Stephen Higgins's Review Sourced from Google

      My relationship with Troy Web Consulting began in 2019, and I am very proud to say it still continues. Their experience and expertise is second to none, and their incredible customer service makes communication between you and your project manager and the team something you look forward to. It has truly been an enjoyable experience growing my company with the help and abilities of such a great group. A special thanks goes out to Anthony and Mark, two of the best to work with.

    • Caring Gene
      Caring Gene Review from Google
      5.0

      Caring Gene's Review Sourced from Google

      Troy Web took over the maintenance and service contract for our in depth healthcare career information and job posting website. Their ability to seamlessly take ownership, clean up and bring our site into a stable wordpress environment was done not only quickly, but also flawlessly. During our time with Troy Web, a number of updates and additional features were required to be built. They were not only able to build these aspects, but also to correct past build issues in the process making the site more reliable on a daily basis. In the last 6 months of their service we didn’t experience any unforeseen downtime with our website, which is extremely important to the function of our site for those that access and use it on a daily basis. Troy Web provides an exceptional service with a team that is always available and very knowledgeable.

    Reviews verified by DesignRush and sourced from the agency's profile View All Reviews
  • Powering Smart Digital Experiences Across Mobile, Software and Web

    8ration drives digital innovation with 10+ years of excellence. As a leading Web Design & Development Company in the USA, we deliver powerful digital solutions across Web Development, Mobile App Development, Blockchain, AI Innovations, and scalable SaaS Platforms...

    Top Services:

    • Software Development
    • eCommerce Development
    • Web Development
    • AI Development
    • Mobile App Development
    • Show more
    Location
    New York City, New York
    Number of Employees
    100 - 249
    Average Hourly Rate
    $100/hr
    Minimal Budget
    $25,000 - $50,000
    Portfolios Count
    29 Projects Listed

    8ration Services

    • Software Development
    • eCommerce Development
    • Web Development
    • AI Development
    • Mobile App Development
    • Blockchain
    • VR/AR
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • RC Event Hub
    • Circle Track Connections
    • Dots Travel
    Data sourced from the agency's DesignRush profile

    8ration Reviews & Testimonials

    • Thomas Garrett
      Thomas Garrett Review from Google
      5.0

      Thomas Garrett's Review Sourced from Google

      Our old Android app was slow and full of bugs, but 8ration rebuilt it from the ground up. The new version runs smoothly, loads instantly, and sports a modern, user-friendly design. Feedback from our customers has been overwhelmingly positive.

    • Ehsaan Azfar
      Ehsaan Azfar Review from Google
      5.0

      Ehsaan Azfar's Review Sourced from Google

      Hello Dear,I hope you're doing well.We provide SEO guest post experts .If you want to buy quality links to grow your online portal, we are with top websites based on tech, business, and fashion.We offer:1. SEO improves your website’s visibility and authority on search engines.2. It includes high-quality backlinks and permanent posts on tech, business, and fashion websites.3. This helps boost your rankings, authority score, and organic traffic for long-term growth.Your time and interest are highly valued.Now, could you please share your next plan for growing your business?Let me know what do you thinkThanks

    • David Cumbie
      David Cumbie Review from Google
      5.0

      David Cumbie's Review Sourced from Google

      I needed an iOS eCommerce app for my boutique store, and 8ration delivered exactly what I had in mind. The app is easy to navigate, secure, and the checkout process is seamless. Sales have gone up since launch.

    Reviews verified by DesignRush and sourced from the agency's profile View All Reviews
  • Vetted Devs On-Demand. Scale Team Fast, Risk-Free.

    Hivex is an outstaffing company that offers a full software development lifecycle, from discovery to quality assurance. Our team of experts focuses on technology-intensive industries and stays up-to-date with the latest IT trends, providing the best solutions for companies worldwide...

    Top Services:

    • Software Development
    • Staff Augmentation
    • DevOps Consulting
    • AI Development
    • Blockchain
    • Show more
    Location
    Miami, Florida
    Number of Employees
    100 - 249
    Average Hourly Rate
    $49/hr
    Minimal Budget
    $25,000 - $50,000

    Hivex Services

    • Software Development
    • Staff Augmentation
    • DevOps Consulting
    • AI Development
    • Blockchain
    • Mobile App Development
    • VR/AR
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • Legarithm
    • Equeum
    • Logicom
    Data sourced from the agency's DesignRush profile

    Hivex Reviews & Testimonials

    • Margaret N.
      Margaret N. Marketer at Elit-Web
      5.0

      Software Development Review from Margaret N.

      It was a pleasure working with Hivex. They quickly grasped the scope of our project and provided highly skilled developers within days. These engineers were efficient and integrated smoothly into our team. They built a robust remote work system that significantly improved our team's collaboration and productivity. The whole process was smooth, and the results were exactly what we needed.

    • Olena Shabunina
      Olena Shabunina CEO at BrandVox
      5.0

      Software Development Review from Olena Shabunina

      We needed to quickly expand our dev team to build out a new feature set, and Hivex helped us find and bring on skilled remote developers to make that happen. The devs hit every deadline we set, sometimes even early. If we needed changes or had questions, they were super responsive - usually got back to us within a couple hours.

    • Isammara Lourenço
      Isammara Lourenço HR Generalist at Snov.io
      5.0

      Software Development Review from Isammara Lourenço

      We had a temporary gap in our technical team due to some transitions, and we needed to keep our development momentum going strong. Hivex provided us with skilled developers who seamlessly integrated into our team. They had the expertise we needed and filled the gap until we made permanent hires. Our collaboration with Hivex made sure our projects kept going without delay, we didn't lose our development momentum, and there wasn't any disruption. It was a huge help during a challenging time.

    Reviews verified by DesignRush and sourced from the agency's profile View All Reviews
  • Transform your business ambitions into measurable outcomes

    Tech strategy advisor & delivery partner with 25+ years of experience. We deliver measurable results through a unique, AI-enabled advisory & delivery framework combining technological heritage with AI-driven optimisation to scale faster, with full governance and compliance...

    Top Services:

    • Software Development
    • Cloud Consulting
    • DevOps Consulting
    • Big Data Analytics
    • IT Services
    • Show more
    Location
    Plano, Texas
    Number of Employees
    500 - 999
    Average Hourly Rate
    $50/hr
    Minimal Budget
    $25,000 - $50,000
    Portfolios Count
    20 Projects Listed

    Future Processing Services

    • Software Development
    • Cloud Consulting
    • DevOps Consulting
    • Big Data Analytics
    • IT Services
    • Digital Strategy
    • Managed Services
    • AI Development
    • Cybersecurity
    • Product Design
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • HAS TECHNOLOGY GROUP
    • THE LINDE GROUP
    • ZEST
    • PARKEON
    • STEAMSHIP MUTUAL
    • TENNECO
    • VALEO
    • MARSTON HOLDINGS
    • KMD
    • 4FINANCE
    Data sourced from the agency's DesignRush profile
  • Let's Dev This

    247 Labs is one of the Top Software Development Companies in Canada, serving industries in Healthcare, Insurance, Finance, Retail and more. Our services include full custom software end to end development and AI...

    Top Services:

    • AI Development
    • Mobile App Development
    • Software Development
    • Web Development
    • WordPress Website Design
    • Show more
    Location
    New York City, New York
    Number of Employees
    50 - 99
    Average Hourly Rate
    $100/hr
    Minimal Budget
    $25,000 - $50,000
    Portfolios Count
    6 Projects Listed

    247 Labs Services

    • AI Development
    • Mobile App Development
    • Software Development
    • Web Development
    • WordPress Website Design
    • eCommerce Development
    • IT Services
    • Web Design
    • Wearables
    • ERP Consulting
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • Rogers
    • GM
    • Motorola
    • Loblaw
    • Ubisoft
    • Coles
    • Johnson&Johnson
    • Guard.me
    • YMCA
    • Gillette
    Data sourced from the agency's DesignRush profile

    247 Labs Reviews & Testimonials

    • Ethan Feltz
      Ethan Feltz Review from Google
      5.0

      Ethan Feltz's Review Sourced from Google

      247 Labs was great to work with. I would recommend them for any software development as they have the expertise to solve complex challenges and create great software.

    • Jesse Axelrod
      Jesse Axelrod Review from Google
      5.0

      Jesse Axelrod's Review Sourced from Google

      All I have to say Ali you’re amazing. Your company did great thanks for getting my business Up and running again I appreciate everything you have done Your patience with me is fantastic. I highly recommend this company to anybody who needs web work. These guys came through for me pulled me out of the gutter from previous web designers and web management. Always will recommend these guys. Thanks Ali to you and your team

    • Kate Ruscito
      Kate Ruscito Review from Google
      5.0

      Kate Ruscito's Review Sourced from Google

      If I could leave 10 stars, I would! Working with 247Labs on our website was one of the best decisions we made. From day one, their communication was clear, consistent, and easy to follow. We always knew what was happening, what was next, and where input was needed.Their team was responsive, open to feedback, and quick to turn ideas into improvements. They didn’t just execute, they brought smart suggestions that made the final product far better than what we initially envisioned.On the technical and design side, they’re INCREDIBLE. Our site is fast, clean, modern, and built with real attention to detail. Every element was expertly crafted and feels unique to us.What stood out most was how supportive they were throughout the entire process. They were patient, proactive, and genuinely invested in getting the best result for us.Absolutely use 247Labs if you need a website. They deliver, and then they go beyond that!

    Reviews verified by DesignRush and sourced from the agency's profile View All Reviews
  • Your Vision, Our Experts with Portal & Mobile Framework, Powerful Results!

    Why build from scratch! Our Portal, Mobile and AI framework provides 30-40% increased time to market. Built with Enterprise Security/Compliance for Azure/AWS clouds. ContentActive (Houston) provides Strategy, UI/UX, Web/Mobile/AI/Automation/IoT & DevOps. Your Vision, Our Experts, Powerful Results!...

    Top Services:

    • Software Development
    • Mobile App Development
    • AI Development
    • DevOps Consulting
    • Web Development
    • Show more
    Location
    Houston, Texas
    Number of Employees
    Under 49
    Minimal Budget
    $25,000 - $50,000
    Portfolios Count
    4 Projects Listed

    ContentActive, LLC Services

    • Software Development
    • Mobile App Development
    • AI Development
    • DevOps Consulting
    • Web Development
    • IoT
    • Big Data Analytics
    • ERP Consulting
    • UI/UX Design
    • Digital Strategy
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • AEI Energy
    • Abitibi-Consolidated
    • American Medical Writers Association
    Data sourced from the agency's DesignRush profile
  • AI & Automation Partner for Mid-Market Businesses

    Frogslayer is the custom software, AI, and automation partner for mid-market businesses in Texas. We work as a senior team on retainer AI consulting, strategy, automation, development, and implementation. Plans start at $2,500/month...

    Top Services:

    • Software Development
    • Mobile App Development
    Location
    College Station, Texas
    Number of Employees
    50 - 99
    Minimal Budget
    $25,000 - $50,000

    Frogslayer Services

    • Software Development
    • Mobile App Development
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • NCR
    • Wrigley
    • Texas A&M University
    • Microsoft
    • National Instruments
    • Lupl
    • Dunkin Donuts
    • AOPA
    • K2 Integrity
    • Schlumberger
    Data sourced from the agency's DesignRush profile

    Frogslayer Reviews & Testimonials

    • May Halpirn
      May Halpirn Review from Google
      1.0

      May Halpirn's Review Sourced from Google

      Curious about another reviewer who looked older, a job applicant, who didn't have his call returned. Frogslayer slung cliche pablum his way. Apparently they hire Jr. Devs but do they hire over a certain age? Do they know the law? Their Senior Dev is under 30 and was hired from being a student employee. Curious and curiouser. Maybe Frogslayer isn't as woke as they appear. Friend of mine went through the ringer with them was told they'd get feedback either way. Instead they got the standard blow off rejection after devoting way too much time on a company that might not value "employees over a certain age." Heads up Frogslayer. There are laws.

    • Jared L
      Jared L Review from Google
      3.0

      Jared L's Review Sourced from Google

      one of the only companies in town actively seeking real beginners/students to become junior level developers using all stacks and not focused on a particular one but most importantly not stuck with legacy tech debt.

    • Heath Phillips
      Heath Phillips Review from Google
      5.0

      Heath Phillips's Review Sourced from Google

      These guys are incredible at what they do. They helped me design a custom software that fit all of my companies needs. The time they spend understanding what my goals were was incredible. They also made tons of suggestions to control the cost. Highly recommend this team!

    Reviews verified by DesignRush and sourced from the agency's profile View All Reviews
  • We Engineer Enterprise AI Development

    Engineered in the US based, delivered by a global team with more than 9 years of enterprise engineering experience and 800+ production systems behind us...

    Top Services:

    • AI Development
    • Mobile App Development
    • Software Development
    • IT Services
    • Staff Augmentation
    • Show more
    Location
    Reston, Virginia
    Number of Employees
    250 - 499
    Average Hourly Rate
    $50/hr
    Minimal Budget
    $25,000 - $50,000
    Portfolios Count
    1 Project Listed

    TechTIQ Inc. Services

    • AI Development
    • Mobile App Development
    • Software Development
    • IT Services
    • Staff Augmentation
    • DevOps Consulting
    • Web Development
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • One Harvest
    • YPO
    • Voista
    • Standard Chartered
    Data sourced from the agency's DesignRush profile

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