Best US Cross-Platform App Development Companies

6 Companies - Rankings updated: September 06, 2026

DesignRush vets all agencies based on professional qualifications and verified customer feedback to help you choose confidently. Some featured agencies maintain paid sponsorships.

United States × Cross-Platform Mobile App Development × Legal × $50,000 & Up × Clear Filters
  • Azumo

    Verified Verified by the DesignRush team for authenticity and credibility.

    Build Intelligent Apps for Web, Mobile, Data, AI and Cloud

    Azumo has been building intelligent apps since 2016, offering expertise in custom native and cross-platform app development. It boasts a 150% client retention rate and a client portfolio of 100+ businesses, including Meta, Omnicon Media Group, and United Healthcare...

    Top Services:

    • AI Development
    • Software Development
    • Staff Augmentation
    • Mobile App Development
    • Big Data Analytics
    • Show more
    Location
    San Francisco, California
    Number of Employees
    100 - 249
    Average Hourly Rate
    $55/hr
    Minimal Budget
    $50,000 & Up
    Portfolios Count
    9 Projects Listed

    Azumo Services

    • AI Development
    • Software Development
    • Staff Augmentation
    • Mobile App Development
    • Big Data Analytics
    • DevOps Consulting
    • Cloud Consulting
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • Discovery Channel
    • Meta
    • Zynga
    • Jostens
    • Assembled Brands
    • NGL
    • NCSoft
    • Twitter
    • Horoscope.com
    • Bento
    Data sourced from the agency's DesignRush profile

    Azumo Reviews & Testimonials

    • Michael S.
      Michael S. Director at Software Development Company
      5.0

      Software Development Review from Michael S.

      We selected Azumo to develop our software. We transitioned from another development company, so Azumo was initially responsible for migrating our existing code and environments. We are currently still working with Azumo as our nearshore software development team on adding new items to our software.

    • Anonymous
      Anonymous CTO at Healthcare Company
      5.0

      UI/UX Design Review from Anonymous

      Azumo helped us migrate our existing UIs into a new framework, creating reusable components and the infrastructure needed for future development. The developer they assigned became a seamless part of our team, always punctual, responsive, and a great fit overall.

    • Anonymous
      Anonymous VP Product & Engineering at Sales & Mktg Software Company
      5.0

      Software Development Review from Anonymous

      Thanks to Azumo’s work, our product is now more scalable, optimized, and ready for a growing user base. Their team has managed the engagement effectively, keeping us updated and addressing any challenges along the way. We’ve appreciated their constant availability and proactive communication.

    Reviews verified by DesignRush and sourced from the agency's profile View All Reviews
  • We Make the Impossible Case Possible.

    Matellio is a leading software engineering studio, recognized globally for delivering intelligent solutions powered by Artificial Intelligence and Machine Learning. We specialize in developing customized AI solutions tailored to various needs of businesses under different industry verticals...

    Top Services:

    • AI Development
    • IoT
    • DevOps Consulting
    • Cloud Consulting
    • Mobile App Development
    • Show more
    Location
    Denver, Colorado
    Number of Employees
    250 - 499
    Average Hourly Rate
    $50/hr
    Minimal Budget
    $50,000 & Up
    Portfolios Count
    26 Projects Listed

    Matellio Inc. Services

    • AI Development
    • IoT
    • DevOps Consulting
    • Cloud Consulting
    • Mobile App Development
    • Software Development
    • Web Design
    • Web Development
    • Big Data Analytics
    • Staff Augmentation
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • Hewlett Packard Enterprise
    • Tracking Genie
    • Brideside
    • Air Fusion
    • vCard Global
    • Codexa
    • PTGI
    • INSPRO
    • NERVVE
    • GoShow
    Data sourced from the agency's DesignRush profile

    Matellio Inc. Reviews & Testimonials

    • Undisclosed
      Undisclosed CTO at V Card Global
      4.7

      Web Development Review from Undisclosed

      Matellio is one of the best organizations I have had a chance to work with. Their unique approach to becoming an integrated extension of our corporate programming staff provides us with the ability to design and implement solutions in an ever changing environment.

    Reviews verified by DesignRush and sourced from the agency's profile View All Reviews
  • Dont settle for off-the-shelf. Expertly crafted & custom-tailored software from the USA.

    K-Optional Software: where your success is our success. From secure solutions that scale to an uncompromising focus on return on investment, we're the company that delivers. Dont settle for off-the-shelf. Expertly crafted & custom-tailored software from the USA...

    Top Services:

    • Mobile App Development
    • Software Development
    • AI Development
    Location
    New York City, New York
    Number of Employees
    Under 49
    Average Hourly Rate
    $200/hr
    Minimal Budget
    $50,000 & Up

    K-Optional Software, LLC Services

    • Mobile App Development
    • Software Development
    • AI Development
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • Viapath Technologies
    • AllModular Systems
    • Assemplify
    • University of Arkansas
    • University of Texas Austin
    • Flowty
    • RepairDispatch
    Data sourced from the agency's DesignRush profile

    K-Optional Software, LLC Reviews & Testimonials

    • Michael Levy
      Michael Levy President at Flowty
      5.0

      Software Development Review from Michael Levy

      Flowty is a blockchain-based platform providing various transaction services around NFTs. K-Optional wears many hats in support of Flowty including Front End, Back End, business strategy, SEO and more. The K-Optional team has been incredible to work with. They are proactive, supportive, smart, thoughtful and, most importantly, fit seamlessly into our team and company culture. To put it succinctly, we tried to hire them full-time...and then tried to buy their company to acqui-hire them. Some of their strengths include: reliability, responsiveness and creativity. There are many groups out there that can perform some version of the work we are looking for. There are not many groups that are responsive at all hours of the day, deliver consistently and able to present data-backed business strategies.

    • Jane Smarovozova
      Jane Smarovozova Creative Director at McSwain
      5.0

      Software Development Review from Jane Smarovozova

      We collaborated with K-Optional to develop a custom inventory management dashboard tailored for real estate clients. We provided the creative vision and detailed designs, while their team focused on the software development, ensuring that every element was implemented perfectly. We worked hand-in-hand flawlessly, resulting in a sleek, user-friendly interface that not only looks great but functions seamlessly. The synergy between design and development allowed us to deliver a product that exceeded client expectations, combining aesthetics with powerful functionality.

    Reviews verified by DesignRush and sourced from the agency's profile View All Reviews
  • We deploy secure AI solutions that deliver positive ROI within weeks.

    NineTwoThree AI Studio is a Boston-based AI agency that builds secure, production-grade AI and ML solutions with measurable ROI. Founded in 2012, our Ph.D.-level engineers and certified product managers have delivered 150+ projects for enterprise brands and startups alike...

    Top Services:

    • AI Development
    • Mobile App Development
    • IoT
    • Software Development
    • DevOps Consulting
    • Show more
    Location
    Danvers, Massachusetts
    Number of Employees
    100 - 249
    Average Hourly Rate
    $99/hr
    Minimal Budget
    $50,000 & Up
    Portfolios Count
    5 Projects Listed

    NineTwoThree Services

    • AI Development
    • Mobile App Development
    • IoT
    • Software Development
    • DevOps Consulting
    • Wearables
    • Software Testing
    • Digital Strategy
    • Product Design
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • FanDuel
    • Consumer Reports
    • VSAC
    • Skylight
    • Raycon
    • K&L Wines
    • Prisonology
    • Dataflik
    • Wheels Now
    • Amerit Fleet
    Data sourced from the agency's DesignRush profile
  • Designing the Digital Future.

    A top custom software development firm dedicated to delivering bespoke digital products that drive innovation and help you achieve your brand goals. A full-stack developer with expertise in every major platform and language, we design and deliver custom applications and host and maintain the solutions we...

    Top Services:

    • Software Development
    • Mobile App Development
    • UI/UX Design
    • Software Testing
    • WordPress Website Design
    • Show more
    Location
    Spring, Texas
    Number of Employees
    Under 49
    Average Hourly Rate
    $150/hr
    Minimal Budget
    $50,000 & Up

    Espresso Moon Services

    • Software Development
    • Mobile App Development
    • UI/UX Design
    • Software Testing
    • WordPress Website Design
    • eCommerce Development
    • Web Development
    • AI Development
    • VR/AR
    • Cloud Consulting
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • DistributionNOW
    • Tesla
    • Nucor Steel
    • Everest Funeral Concierge
    • Flexitallic
    • Solvay Dental
    • Stream Realty
    • Wilson Perumal
    • Neuhaus Academy
    • SafeFleet
    Data sourced from the agency's DesignRush profile

    Espresso Moon Reviews & Testimonials

    • Bradley Collins
      Bradley Collins Review from Google
      5.0

      Bradley Collins's Review Sourced from Google

      Working with the guys at Espresso Moon (Scott, Doug, Tim and Dwayne) was truly a great collaboration and experience. They didn't just throw a website together for us, they helped us to reinvent ourselves. They go out of their way to get to know you and your business to the fullest extent, and that is a quality that is not often seen. If I were to recommend a web design/hosting company to anyone, Espresso Moon would be the one and only name I give. Thank you for your service and support!

    • Meredyth Jones
      Meredyth Jones Review from Google
      5.0

      Meredyth Jones's Review Sourced from Google

      I worked primarily with Scott, Tim and Doug to build a fairly complicated site: Paypal/credit card payments, video training modules, a graded quiz, and issuance of a completion certificate. They were the only website company that invited me to an in-person meeting and that was tremendously helpful in me understanding how they work and them understanding my goals. Large Animal Consulting & Education launched 2 days ago and the site is running smoothly. I'm very happy with the site they designed (they also designed my logos) and am looking forward to using them to support and add to the site down the road.

    • Caleb Schallert
      Caleb Schallert Review from Google
      5.0

      Caleb Schallert's Review Sourced from Google

      Doug Wheeler is the owner of Espresso Moon and he has provided my small business excellent IT technical support for our website. His team helped me out by removing malicious code that was affecting my site right after the Heart Bleed epidemic last year. He got my site back up and running so i could continue business and save my online reputation. I would recommend Espresso Moon LLC to anyone in need of a new website or mobile application because they follow through with what they promise to do, on time and on budget. They are truly a pleasure to work with!

    Reviews verified by DesignRush and sourced from the agency's profile View All Reviews
  • Active Bridge is a full-stack development partner responsible for developing.

    Active Bridge is a full-stack development partner responsible for developing and maintaining websites, mobile applications and software systems. We provide dedicated programmers who have extensive experience in Ruby on Rails development across a variety of industries for in-house teams...

    Top Services:

    • UI/UX Design
    • Staff Augmentation
    • Mobile App Development
    • Web Development
    • Show more
    Location
    Phoenix, Arizona
    Number of Employees
    Under 49
    Average Hourly Rate
    $30/hr
    Minimal Budget
    $50,000 & Up

    Active Bridge Services

    • UI/UX Design
    • Staff Augmentation
    • Mobile App Development
    • Web Development
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • UpStack
    • DaisyBill
    • EverSeat
    • Mediprocity
    • SplitPayment
    • FreeStak
    • Beatthread
    Data sourced from the agency's DesignRush profile

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