Custom Web App Development Services

Upsilon is a web development company that covers the complex of the most diverse web solutions: from one-page landings to enterprise-grade web applications.

Being accomplished in both back-end and front-end sides of the professional web development services, we ensure your software's high performance, scalability, portability, and security.

Web Development Services We Offer

Upsilon Back-end development

Back-end development services

Leverage Upsilon’s web app development services for building back-ends that perform fast, provide secure and reliable data storage, and scale on demand to meet your business needs.

Drawing on our experience in Python, Django, and other programming languages and development frameworks, we will help you design the core of your web-based application — with an eye for availability, robustness, and great new features.

Whether your project needs a custom API, be it GraphQL or REST - our architects and senior engineers will get you covered.

Front-end development services

Our front-end developers deliver visually rich and highly interactive custom web development solutions that attract, engage, and convert.

We can help you balance the stunning UI equal to the market-leading software products with the business logic of your web, mobile, and SaaS applications.

With React JS in the core of our custom web development services, we deliver high-performing apps without compromising your users' experiences.

Upsilon Front-end development


Types of Custom Web Applications We Build

Leverage our web development services to develop cutting-edge B2B and B2C web solutions with outstanding UX/UI design, robust architecture, increased scalability, and advanced functionality.

Internal Web Applications

As a company providing custom web app development services, we deliver software that helps businesses streamline internal processes and operations: project, resource, and financial management, workflow automation, communication within and between teams, and more.

SaaS Applications

Take advantage of the SaaS flexibility and scalability powered by Upsilon’s web application development services and boost your business’ bottom line with a robust subscription-based platform.

Whether you need to develop specific SaaS components like APIs or implement integrations like Stripe, our SaaS developers are at your service.

Two-sided Marketplace Systems

If you need to develop a feature-rich two-sided marketplace system - we will get you covered. By leveraging our expertise in this domain, businesses can receive tangible benefits from the network effects created through the commercial interaction between sellers and buyers.

AI/ML Web Applications

Drawing on our experience in NLP/NLU, we deliver AI-based and machine learning web solutions, including intelligent chat apps for logistics and supply chain management, banking and finance, e-learning, healthcare, and other business domains.

Decentralized Applications (DApps)

By offering a full spectrum of custom web application development services, we help businesses unfold the potential of blockchain technology.

Our blockchain developers are proficient in leveraging the Ethereum and web3.js technology capabilities to build a solution that will help your company stay on the competitive edge in the decentralized applications world.

Location-based Web Applications

From applying GPS and iBeacon technologies and mapping service integrations to developing complex route-planning, geofencing, or navigation apps, we help our clients implement location-based technologies into their web products, services, and business processes.

Our Featured Case Studies in Web Development

Turn to Upsilon’s web development services to create best-in-class software solutions that perfectly fit your business needs. The results we deliver to our clients are reflected in our projects. Check them out.

View case studies

Looking for a company to fulfill your needs in web app development services?

Upsilon has more than 50 software engineers, QA experts, designers, data scientists, and DevOps who are ready to lend a helping head in the web development process, empowering your business.

Let’s talk

Technologies We Use for Web Development

As a leading web development company, Upsilon utilizes the most cutting-edge front-end and back-end technologies.

We meticulously analyze all aspects of each business and offer the best-suited combination of front-end and back-end technologies to fulfill your project requirements.


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

Advantages of Our Top-notch Web Development Services

Have web development initiatives on your company roadmap? Count on Upsilon’s custom web development services to strengthen your competitive edge by implementing and propelling to market the most advanced web-based software.

Upsilon knows how critical it is to fulfill clients’ requirements. Whether you need a turnkey, optimized, and visually stunning web app or need a fault-tolerant server solution and fast API to empower an existing solution, we will bring our professional web development services to the table.

Rich Features

Keeping in sync with each project’s specific, we are ready to deliver an unparalleled solution craftly tailored to your business needs and equipped with features of any complexity: from push notifications and social media integration to in-app payments, custom big data analytics, and AI-based functionality.

Superior User Experience

Whether it’s a web app or website development, UX and UI are central pillars the user experience rests on. For UpsilonIT, delivering a top-class design means increasing user satisfaction and advancing their usability, accessibility, and efficiency with the website or app.

Flawless Integrations

Using a wide variety of integration tools and APIs, we enrich the functionality of web applications while accelerating time-to-market and reducing costs. With our web development services you will seamlessly connect your application with leading third-party software, be it ERP, CRM, payment, or analytical systems.

100% Security

We ensure your web solution protection at all levels: from user access and payment to digital signatures and data encryption. Our custom web app development services include code analysis and thorough testing that guarantees that your product will comply with all the industry's security standards.

Build a custom web application with Upsilon

Within its portfolio of custom web development services, Upsilon offers:

  • Business analysis for a well-rounded and in-depth understanding of the goals, scope, and limitations
  • Intuitive and responsive design to improve customer retention and loyalty
  • Stable, lightning-like, and error-free performance of your web solution
  • Regular updates to keep your product up to date and keep it competitive
Get a free consultation
Web Application with Upsilon

Agile Web 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.

Why Choose Our Custom Web Application Development Services

Benefits of choosing Upsilon as a web app development company:
35+ highly-qualified developers, flexible and adaptable in terms of innovation and cooperation
QA engineers, ensuring superior software quality during the whole project lifecycle
PMs with more than 3-5 years of commercial experience, guaranteeing on-time & on-budget delivery
UX/UI designers to ensure the best user experience with the combination of design trends and brand recognition
Agile web development services and processes to provide ongoing support and maintenance
More than 20 custom software solutions delivered through the deep focus on technology


What are the web development services?

Web development services encompass a set of tasks associated with creating web-based solutions working via intranet or the internet.

More broadly, web development implies a certain sequence of activities and operations required to design, build, deploy, maintain and update a website or a web app to ensure user-friendliness, stability, and error-free performance.

What does a web development company do?

To build a web app or a website from scratch, a web development company typically completes the following scope of work:

  • Ideation and product concept development;
  • Choosing the best-suited technologies to deliver a web app according to the requirements;
  • Building a solution architecture;
  • Back-end web development: coding and programming:
  • Integration with 3rd party software: media, payments, video, etc.;
  • Publication of content and its optimization;
  • Front-end web development: UX and UI design;
  • Testing the app before it goes live (beta testing);
  • Identification of problems and bug fixing;
  • Implementing improvements and deployment;
  • Product maintenance and regular updating.

How much does it cost to build a custom web application?

The cost of web development services can vary greatly and mostly depends on two main factors: the complexity of web functionality and the hourly rate of developers (you may choose between having an in-house team or hiring an outsource tech partner).

A professional web app with medium functionality (landing pages, admin panel, user management, third-party integrations, database integration, etc.) can be developed within the range of $15,000-50,000.

The price for complex enterprise-grade web systems that need to maintain big data, handle thousands of users simultaneously and provide 360° security can go up to $100,000 and higher. Each complex solution is custom-made to meet the client’s requirements. 

What are the best technologies used in web application development services?

Programming languages and frameworks used for web application development services can be divided into back-end technologies and front-end ones.

Python, Java, PHP, and C# are the most popular back-end languages. Among the front-end technologies, the leading positions are occupied by JavaScript, React, Angular, Vue.js. 

While considering what programming language to choose for web development, consider the size and complexity of the application, extensibility, time, money, and team available. All projects are unique and require different tech stacks.

What Our Clients Say

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

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

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