Searching for a top-rated application modernization services company to future-proof your business? Our directory provides industry-leading experts specializing in transforming legacy systems. With insights from verified client experiences and success stories, we make it easy for you to compare options based on location, budget, and hourly rates to find your next agency partner. 

Best App Modernization Services Agencies

8 Companies-Rankings updated: September 03, 2026

All mobile app development firms on DesignRush have been assessed for their expertise, portfolio, and verified client reviews. Some listings may be paid.

Application Modernization Services × Crypto × $25,000 - $50,000 ×Clear Filters
  • Product Design & Engineering for Banks, Fintechs, and Enterprise Platforms

    Alty specializes in high-stakes mobile app development for fintech and banking, uniting strategy, design, and engineering under a single senior lead per engagement. A 4x Red Dot Award winner, it has built products used by 60M+ active users across 40+ markets...

    Top Services:

    • Mobile App Development
    • Design Services
    • Software Development
    • Web Design
    • UI/UX Design
    • Show more
    Location
    Cascais, Portugal
    Number of Employees
    50 - 99
    Average Hourly Rate
    $75/hr
    Minimal Budget
    $25,000 - $50,000
    Portfolios Count
    22 Projects Listed

    Alty Services

    • Mobile App Development
    • Design Services
    • Software Development
    • Web Design
    • UI/UX Design
    • Web Development
    • AI Development
    • Software Testing
    • Market Research
    • Product Design
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • VISA
    • Mastercard
    • Raiffeisen
    • Monobank
    • GTBank
    • PrivatBank
    • ABA Bank
    • CBH Bank
    • Renovite
    • Corezoid
    Data sourced from the agency's DesignRush profile

    Alty Reviews & Testimonials

    • Ewa Koltunczyk (Karabon)
      Ewa Koltunczyk (Karabon) Regulatory Specialist II at CID LINES, An Ecolab Company
      5.0

      Mobile App Development Review from Ewa Koltunczyk (Karabon)

      I recently had the pleasure of working with Alty to develop our mobile app. We needed a developer who was able to translate my vision and provide technical guidance. The experience has been nothing short of outstanding. From the initial consultation to the final product, Alty's professionalism, expertise, and dedication have exceeded my expectations. Alty has demonstrated a deep understanding of mobile app development and was willing to go the extra mile. Their ability to translate my ideas into a seamless, user-friendly, and visually appealing app is truly impressive

    • Adam Kubas
      Adam Kubas Director at Institute of Physical Chemistry PAS
      5.0

      Mobile App Development Review from Adam Kubas

      Alty did excellent work for our department. The team prepared a high-quality and easy-to-understand development roadmap for Virtual Academy of Bioinformatics. Their positive attitude and willingness to learn made them a pleasure to work with. Overall, I highly recommend Alty for any development role. They have the skills, dedication, and professionalism to excel. Thank you for developing our app.

    • Rajesh Kasturirangan
      Rajesh Kasturirangan Founder at Socratus
      5.0

      Web Development Review from Rajesh Kasturirangan

      The team at Alty is indeed filled with tech engineers and assiduous individuals with excellent software development skills! The end product work had minimal bugs. Alty has exceptional communication skills, identifies top talent, and goes above and beyond to ensure a smooth development.

    Reviews verified by DesignRush and sourced from the agency's profile View All Reviews
  • Mobile & Web Software Dev Team

    Kernelics is a boutique web and mobile software development firmfor startups and tech companies...

    Top Services:

    • Mobile App Development
    • Staff Augmentation
    • Product Design
    • Software Development
    • eCommerce Development
    • Show more
    Location
    London, United Kingdom
    Number of Employees
    50 - 99
    Average Hourly Rate
    $40/hr
    Minimal Budget
    $25,000 - $50,000
    Portfolios Count
    18 Projects Listed

    Kernelics Services

    • Mobile App Development
    • Staff Augmentation
    • Product Design
    • Software Development
    • eCommerce Development
    • IT Services
    • Web Design
    • Software Testing
    • Web Development
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • Small Business Industry
    • Fintech Industry
    • Marketing Industry
    Data sourced from the agency's DesignRush profile

    Kernelics Reviews & Testimonials

    • Dzmitry Novikau
      Dzmitry Novikau Co-Founder at Obsidian AI
      5.0

      Staff Augmentation Review from Dzmitry Novikau

      I worked with Kernelics on a crypto project where we needed help with both design and development. From the beginning, the team was easy to communicate with and clearly understood what we were trying to build.The designer improved our initial ideas by making the user experience more intuitive. They suggested better ways to structure the navigation and user flow, which helped reduce friction and made the product easier to use.We also brought in one of their developers, who worked alongside our existing team member. They collaborated well, completed the work on time, and handled some challenging parts of the exchange functionality without any issues.Overall, Kernelics delivered quality work, stayed within budget, and were professional throughout the process. I’d recommend them to others looking for a reliable design and development partner, especially for crypto or fintech projects.

    • Stsiapan Kolesau
      Stsiapan Kolesau CEO at Module Technology
      5.0

      Web Development Review from Stsiapan Kolesau

      I CEO at the construction company specializing in modular buildings and their components. With years of experience and multiple projects, we decided to expand our online presence beyond our two existing landing pages. We needed a corporate portal to showcase products, manage content easily, and dynamically calculate product costs.On a recommendation, we chose Kernelics, and their organized approach and clear task division impressed us from the start. They began with an in-depth analysis of our needs and a competitive review. For the design, we requested a minimalist style, and the results were spot on, requiring only minor tweaks to meet our expectations.For development, Kernelics selected React, Next.js, and TypeScript, with Strapi for the admin panel. They also integrated Google Sheets to handle dynamic price calculations, enabling instant updates on the site by simply modifying the spreadsheeta feature weve found incredibly useful.Now, two years later, the portal continues to support our growth, and were planning new developments for our main site.Kernelics stood out for their transparent approach and professionalism at every stage, and I confidently recommend them to anyone seeking a reliable web development partner.

    Reviews verified by DesignRush and sourced from the agency's profile View All Reviews
  • UK's #1 Mobile App Development Company

    We help clients achieve transformative digital experiences through App Development. Stakk’s unparalleled skills in iOS, Android, Flutter, and React Native consistently deliver impressive results for brands like LNER Trains and The British Museum. Let’s elevate your product with expert design, management...

    Top Services:

    • Mobile App Development
    • Software Development
    • AI Development
    • UI/UX Design
    • Show more
    Location
    London, United Kingdom
    Number of Employees
    Under 49
    Average Hourly Rate
    $50/hr
    Minimal Budget
    $25,000 - $50,000
    Portfolios Count
    6 Projects Listed

    Stakk Services

    • Mobile App Development
    • Software Development
    • AI Development
    • UI/UX Design
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • LNER
    • The British Museum
    • Safestyle
    • Sotheby's
    • MyCoach
    • Nivoda
    • Gigl
    • Lapland
    • Tracker
    • Volopa
    Data sourced from the agency's DesignRush profile

    Stakk Reviews & Testimonials

    • Natasha Beavis
      Natasha Beavis Founder at Flash Learning
      5.0

      Mobile App Development Review from Natasha Beavis

      We worked with Stakk to develop our mobile revision app for both iOS and Android, and we couldn't be happier with the results. From the first meeting, their team demonstrated exceptional professionalism, technical expertise, and a genuine commitment to bringing our vision to life.They took the time to understand our goals, offered valuable insights to improve user experience, and delivered a sleek, high-performance app that exceeded our expectations. Communication was seamless throughout the entire process, updates were timely, feedback was welcomed and implemented quickly, and every milestone was met on schedule.Post-launch, they've continued to be a reliable partner, providing support and updates as needed.If you're looking for a top-tier mobile app development company, look no further than Stakk. They're a rare find in the tech world and we would highly recommend them.

    • Manfred Olbrich
      Manfred Olbrich CEO at Education Technologies Limited
      5.0

      Software Development Review from Manfred Olbrich

      Stakk has delivered a high-quality product that we are pleased with. Their hybrid model offers great value for money and grants clients to strong technical capacity but also direct contact with management in the UK which really helps with transparency, communication, and ensuring the project is being delivered on thime. The team suggests improvements and meets most deadlines.At the start of the project, I drafted a huge product requirements document that included all the user journeys, my vision for the brand, including the colors and the rest of the brand, and the desired functionalities. I gave this document to Stakk, and they've executed the requirements.

    • Ben Smith
      Ben Smith CEO at Itsfine
      5.0

      Mobile App Development Review from Ben Smith

      We partnered with Stakk to build the mobile platform for #itsfinea unique, flexible weight loss concept launched pre-seed. From the outset, their team, led by Girish and Vikas, brought impressive technical and creative capabilities to the table. Communication was smooth throughout, whether through shared Slack channels or direct contact with the project manager.We collaborated closely with their UX/UI designer in daily stand-ups, and bi-weekly check-ins with the PM ensured the project stayed tightly aligned with our goals. Their process-driven approach matched ours wellevery phase was mapped out clearly, and any changes we needed to make along the way were actioned quickly and without fuss.Stakks professionalism, attention to detail, and focus on client success stood out. Their structured way of working gave us real confidence in the final product. We strongly recommend them to any founder or team looking for a trusted, high-performing partner to bring their product to life.

    Reviews verified by DesignRush and sourced from the agency's profile View All Reviews
  • Software & Enterprise Solutions.

    Ultimate Systems develops dependable, custom-built backend systems, web, and mobile applications that enhance business operations worldwide. Our bespoke IT solutions are designed to meet your unique business needs, ensuring optimal performance and growth...

    Top Services:

    • UI/UX Design
    • eCommerce Development
    • Software Testing
    • AI Development
    • Blockchain
    • Show more
    Location
    Krakow, Poland
    Number of Employees
    Under 49
    Average Hourly Rate
    $35/hr
    Minimal Budget
    $25,000 - $50,000
    Portfolios Count
    4 Projects Listed

    Ultimate Systems Services

    • UI/UX Design
    • eCommerce Development
    • Software Testing
    • AI Development
    • Blockchain
    • Mobile App Development
    • Software Development
    • Big Data Analytics
    • DevOps Consulting
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • Kamaz
    • Regamet
    • Academy of Fine Arts in Krakow
    • Polin Museum of the History of Polish Jews
    • Schulz Brand Friendly
    • Uniprofil
    • Znak
    • Free Walkative Tour
    • Matras
    Data sourced from the agency's DesignRush profile

    Ultimate Systems Reviews & Testimonials

    • michaÅ‚ czeluÅ›niak
      michał czeluśniak Review from Google
      5.0

      michał czeluśniak's Review Sourced from Google

      We had the pleasure of partnering with Ultimate Systems to bring our vision to life for Fabryka Magika's online presence. As a company dedicated to spreading positivity and appreciation through unique gadgets, it was crucial for us to find a web development partner who could effectively convey our message to our audience. Ultimate Systems exceeded our expectations by delivering a visually stunning and user-friendly website that perfectly encapsulated Fabryka Magika's ethos. Their expertise in implementing advanced functionalities ensured seamless transactions and an enhanced shopping experience for our customers. Additionally, Ultimate Systems' commitment to understanding our brand values and translating them into innovative design elements and interactive features truly set them apart. We couldn't be happier with the results of our collaboration, and we highly recommend Ultimate Systems to anyone looking for a reliable and creative web development partner.

    • Hadrian
      Hadrian Review from Google
      5.0

      Hadrian's Review Sourced from Google

      Ultimate Systems delivered outstanding results in developing our financial system. Their innovative approach, commitment to inclusivity, and track record of success set them apart from competitors. Throughout the project, they demonstrated exceptional project management, timely delivery, and proactive responsiveness. Their dedication to promoting financial inclusivity was particularly impressive. Although there's room for improvement in transparency, Ultimate Systems' exceptional services made them invaluable partners in our project.

    • Dv Hacv
      Dv Hacv Review from Google
      5.0

      Dv Hacv's Review Sourced from Google

      We had the pleasure of working with Ultimate Systems to develop an exceptional e-commerce solution for our company, Animille. From the initial consultation to the final implementation, Ultimate Systems demonstrated unparalleled expertise and professionalism. Their team meticulously crafted a visually stunning website that perfectly showcased Animille's diverse product range. The integration of secure payment processing functionalities was seamless, ensuring our customers' transactions were safe and efficient. Additionally, their expertise in backend systems resulted in smooth inventory management and order fulfillment processes. The final product exceeded our expectations, offering users a seamless shopping experience with streamlined navigation and optimized product listings. We highly recommend Ultimate Systems for any e-commerce project!

    Reviews verified by DesignRush and sourced from the agency's profile View All Reviews
  • Web, Mobile and IoT solutions. Made easy.

    We are CimpleO, an award-winning production studio that delivers on time and budget. Since 2012.We develop custom software, complex web services, desktop applications, client-server systems, elegant web, and mobile apps as well as IoT solutions that are made to scale...

    Top Services:

    • eCommerce Development
    • Web Development
    • Web Design
    • IoT
    • Software Development
    • Show more
    Location
    Phuket, Thailand
    Number of Employees
    Under 49
    Average Hourly Rate
    $50/hr
    Minimal Budget
    $25,000 - $50,000

    CimpleO Services

    • eCommerce Development
    • Web Development
    • Web Design
    • IoT
    • Software Development
    • Mobile App Development
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • Redsqware
    • HP
    • Century21
    • W1
    • Shout Factory
    • CEIC
    • JOC
    • IHS
    • POD10
    Data sourced from the agency's DesignRush profile
  • We Design, Develop and Deliver.

    At Cinnova, we treat your business as our own, combining design-thinking, engineering, and business acumen to solve complex challenges. Our flexible engagement models ensure tailored solutions that drive growth and efficiency...

    Top Services:

    • Web Development
    • Mobile App Development
    • Software Development
    • UI/UX Design
    • Web Design
    • Show more
    Location
    Cincinnati, Ohio
    Number of Employees
    100 - 249
    Minimal Budget
    $25,000 - $50,000

    Cinnova Technologies LLC Services

    • Web Development
    • Mobile App Development
    • Software Development
    • UI/UX Design
    • Web Design
    • SEO
    • Big Data Analytics
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • University of Cincinnati
    • HP
    • ProCamps Worldwide
    Data sourced from the agency's DesignRush profile

    Cinnova Technologies LLC Reviews & Testimonials

    • Kyle Neely
      Kyle Neely Review from Google
      1.0

      Kyle Neely's Review Sourced from Google

      Sketchy method of cold calling to get leads by claiming they talked to someone else at my org that they did not in fact talk to. Called on my personal cell phone. Would not do business with them if the engage this this type of misleading lead generation.

    • First
      First Review from Google
      1.0

      First's Review Sourced from Google

      Sketchy people would be a polite way to put it.Kept sending advertisements to a general email box, I responded asking to unsubscribe, they started sending those advertisements to the email from which I responded.I wouldn't trust these people to do anything.

    Reviews verified by DesignRush and sourced from the agency's profile View All Reviews
  • Empowering Innovation, Driving Change.

    DuckMa is a seasoned mobile app development agency that elevates businesses to new heights through innovative digital solutions. With over a decade of experience, DuckMa employs a unique method that transforms visionary ideas into reality, delivering advanced software and mobile applications. The agency...

    Top Services:

    • Digital Services
    • Product Design
    • Digital Strategy
    • IoT
    • AI Development
    • Show more
    Location
    Rezzato, Italy
    Number of Employees
    Under 49
    Average Hourly Rate
    $149/hr
    Minimal Budget
    $25,000 - $50,000

    DuckMa Services

    • Digital Services
    • Product Design
    • Digital Strategy
    • IoT
    • AI Development
    • Mobile App Development
    • Software Development
    • Blockchain
    • Wearables
    • Cloud Consulting
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • RIB
    • arriva
    • amiko
    Data sourced from the agency's DesignRush profile

    DuckMa Reviews & Testimonials

    • niccolò calandri
      niccolò calandri Review from Google
      2.0

      niccolò calandri's Review Sourced from Google

      Unfortunately we didn't find ourselves in terms of development methodology and results. The work was not only late but was not even complete.When asked to do the bare minimum, they asked us for more money.After loud complaints, they restarted the development and completed the guaranteed minimum. Edited review.

    Reviews verified by DesignRush and sourced from the agency's profile View All Reviews
  • Accelerating Software Innovation With AI-Native Engineering

    Engenious is an AI-native quality engineering partner helping startups and enterprise teams build and deploy software with confidence. We specialize in advanced QA automation, AI model validation, and mobile quality engineering, enabling organizations to accelerate release cycles while reducing risk. From...

    Top Services:

    • Mobile App Development
    • Web Development
    • AI Development
    Location
    Las Vegas, Nevada
    Number of Employees
    Under 49
    Average Hourly Rate
    $75/hr
    Minimal Budget
    $25,000 - $50,000

    EnGenious Services

    • Mobile App Development
    • Web Development
    • AI Development
    Data sourced from the agency's DesignRush profile, its website, and other relevant accounts
    • Phoenix Life Sciences
    • Grammarly
    • Sage Company
    • Weedar
    • Pango
    • Superhuman
    • Forte Group
    • Elite Fleet Group
    • Emerge
    • GoChamp
    Data sourced from the agency's DesignRush profile

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