Custom web applications

Upsilon is a web app development company that builds high-tech web-based solutions of any complexity - from two-sided marketplaces to AI/ML applications.

Our experts leverage superior market know-how and the best-in-class technologies for web application design and development. Our solutions will raise your brand awareness, increase conversions, boost customer engagement and help your digital business get ahead of competition.

Highlights of Our Custom Web Apps

We create impactful, efficient, and easy-to-use corporate and customer-facing web apps.

High performance

We make the most of performance engineering to ensure utmost performance of your web apps. Whether it’s a geo-based application set to support thousands of locations, or a multi-vendor marketplace, we’re here to enable glitch-free experiences.

Integration capabilities

By utilizing third-party integrations, we can add the best possible features to your software solution. Improve your web app with well-built microservices, video & text messaging, reporting and analytics functionality, and more.


Security is our priority in web app development. With end-to-end encryption, two-factor authentication, robust user access management implemented, all data, processes and operations within your web app will be maximally protected.


Using our vast experience across web application development projects, we will create a custom solution that will function without a hitch right after the deployment and in future, as your business grows.

we also build:

Custom web applications we build

Web Portals

Web Portals

Our long-term experience in web portal development helps us to deliver the best result for our clients. We apply the most effective technologies to develop enterprise-grade and customer-focused, partner/vendor, learning, healthcare and other types of web portals.

Our well-trained developers know how to implement all necessary functionality and represent it in a user-friendly format. Upsilon can also develop and test websites that can handle a huge number of user traffic and requests without system failures. Web portals with a high-load scalable architecture function smoothly and reliably allowing you to provide an engaging UX and increase ROI.

Progressive Web Applications

Introduced and promoted by Google, PWA is recognized by Gartner as the one to substitute more than 50% of mobile native apps. This technology makes it possible to combine the best features of browsers and mobile apps, i.e. PWAs offer an alternative way to target and engage users and increase conversions. Why PWAs instead of web apps?

  • They act as web pages but let you engage with customers through push notifications;
  • They work across platforms and deliver a native-like user experience;
  • They work when users have a weak or unstable Internet connection thanks to the Service Workers’ technology;
  • They sync in the background and receive over-the-air updates without user interaction.
Progressive web applications
Single-page Applications

Single-Page Applications

Tap into our single-page application development services to stay competitive on the web and uncover a host of benefits for your business. We utilize the latest technology to deliver fast, efficient and flexible applications with cross-browser compatibility.

Upsilon’s engineers will combine the best features of single-page applications (SPAs) to ensure excellent performance of your solution while providing end-users with a seamless web experience.

Technologies We Use for Web Application Development

We meticulously analyze all aspects of each business and offer the best-suited combination of programming languages, frameworks, libraries, and tools to complete clients’ requirements to the fullest extent possible.


Upsilon Python
Upsilon Django
Upsilon Node JS
Node JS
Upsilon FastAPI


Upsilon React
Upsilon Next JS
Next JS
Upsilon Gatsby


Upsilon Amazon EC2
Amazon EC2
Upsilon AWS CloudFront
AWS CloudFront
Upsilon Amazon S3
Amazon S3
Upsilon Amazon RDS
Amazon RDS
Upsilon AWS Lambda
AWS Lambda
Upsilon Google Cloud Platform
Google Cloud Platform

Our projects

View case studies

Agile Web App Development Process

We follow a low-risk web development process underpinned by continuous delivery and seamless integration into the client’s release cycle from the discovery phase through design, development, QA, and maintenance.

Discovery & Planning

This stage aims to analyze your project vision, identify potential risks and benefits, and define business goals.

Our specialists study and refine, if needed, project requirements to elaborate the best-suited tech stack, outline the project milestones, and opt for a most effective engagement model.


From sketching & wireframing to pixel-perfect user interface design - we provide a full range of services that will make your web solution stand out in the market. By collaborating with our clients in Figma, we provide real-time involvement in the design process.


We apply cutting-edge web development technologies and practices to create flexible, full-featured, and robust web software solutions for your business.


We take care of product quality and ensure 100% stability and error-free performance of your web solution. We offer a wide range of testing services, including UX/UI tests and automated tests for complex projects.


In this step, we transfer the project to the client’s hosting, connect the domain and test it on the production server. By combining the benefits of Docker containers and Kubernetes, we adhere to a well-established process of application deployment, scaling, and management.


Through continuous monitoring and troubleshooting, performance audit, and user feedback analysis, we accelerate new features implementation while speeding up the release cycle.


Iterative development creates the conditions for quicker improvements and faster releases, contributing to early value delivery while ensuring stable and error-free functioning of the web solution.

These Companies Trust Upsilon

ThoughtSpotLiveArtCargGoCollectriumMake it Donate
ThoughtSpotLiveArtCargGoCollectriumMake it Donate

They've been LiveArt's partners since our launch, growing with us from a handful of team members to over 20 cross-functional developers.

David Letourneau

David Letourneau

COO at LiveArt

As a non-technical founder, I searched for a tech partner I could trust. The Upsilon team was amazing and hands down the best specialists I could have asked for.

Paul Fallon

Paul Fallon

Founder & CEO at Impromptu Limited

Their team had an ease of communication, but the most impressive thing about them is each member's integrity and work ethic.

Matt Wong

Matt Wong

CTO, Civic Connect

We were excited to have a partner with strong coding skills who compiled everything according to the tech specifications.

Kenny R. Lienhard

Kenny R. Lienhard

CTO, Medignition Inc

Ready to get started?

Scale your product and move to the next stage faster with Upsilon.

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