Belitsoft > API Integration Services | Custom API Development Company

API Integration Services | Custom API Development Company

Belitsoft is an API development and integration company with a development center in Eastern Europe. We have been providing top-quality API development and API integration services since 2012.

API Development Services

Custom API development

We create custom APIs to improve the existing software, making it easier to share data in real time and automate workflows. If you're looking for custom application development companies to handle your API development and integration tasks, consider hiring a dedicated development team of experienced API specialists from Belitsoft.

API consulting

We will analyze your current processes and architecture, assist in strategizing and planning, and help identify and mitigate potential issues. With our extensive experience, we can guide you in selecting API management and API integration solutions that cater to all your needs. Our recommendations are developed based on rigorous analysis, considering code, processes, security and architecture.

Mobile API development

We create APIs that enable payments, appointments, geolocation services, and more, to enrich your mobile applications. Get seamless integration of data from multiple sources like servers, databases, GPS, messaging systems, and LDAP repositories right into your mobile app. We secure your data and implement the capability to mash it up with other data sources. We make this integrated data readily available to your development team, empowering them to build versatile applications.

Web API development

Our team specializes in creating user-friendly and secure web APIs. Comprehensive documentation details every class, method, and possible API response, making it easy for API users to get started. With a changelog available for every API version, users will know exactly how to upgrade seamlessly. Our APIs can support JSON, YAML, and XML and more. We employ token-based authentication and OAuth 2, all of which are reinforced with SSL to ensure that your data remains secure. We use language-specific libraries that are compatible with a wide range of programming languages. Whether it's Node, PHP, Python, Ruby, or even specialized languages like Erlang or Haskell, our APIs are designed for easy adoption.

REST API Development

We build RESTful APIs across an array of languages, platforms, and frameworks. We are capable of designing your REST API from scratch.

In the context of the rising demand for cloud-based services and microservices, our RESTful APIs offer an efficient way to access and organize web services. REST calls are stateless, enabling easy redeployment and scalability.

Our team is experienced in tackling common REST API challenges such as maintaining endpoint consistency, managing API versioning, minimizing long response times and excessive data errors, enhancing security, handling authentication, and ensuring comprehensive API testing.

Hire us to build robust, efficient, and future-ready API solutions tailored to your needs or to perform API modernization for your current solution.

API integration

Cloud API Development

Cloud computing uses APIs to connect different platforms and services. PaaS APIs provide access and functionality for a cloud environment, including integration with databases, messaging systems, portals, and storage components. SaaS APIs connect the application layer with the cloud and underlying IT infrastructure. IaaS APIs help control specific cloud resources and their distribution, such as the rapid provisioning or de-provisioning of cloud resources, network configurations, and workload management. Cross-platform and cloud provider APIs allow for greater cross-platform compatibility and provide the ability to access resources from multiple cloud providers and platforms, saving time and development effort.

AWS API Development

Our API design focuses on scalability, capable of handling a few requests to millions within a short period. We employ Amazon API Gateway to create, publish, maintain, monitor, and secure your REST APIs. In case you require merging data from diverse sources into a unified endpoint, we can establish a GraphQL API using Amazon AppSync. Additionally, we configure API Gateway usage plans, allowing you to present them as product offerings to your clients with customized API quotas and access controls. We can use language-specific frameworks to build and host your APIs on AWS with AWS Compute and Elastic Load Balancing techniques.

For SaaS API delivery models, we implement a multi-tenant API design. To guarantee a seamless migration, we suggest hosting both new and older API versions for a while. Simultaneously hosting multiple API versions on one platform can meet budget constraints, but separating them is recommended for smooth performance.

Azure API Development

In Azure cloud-native development, API development is often essential due to the prevalence of microservices-based architectures; however, during an Azure cloud migration, API development may also become necessary for integrating existing services or adding new functionalities.

Leveraging Azure's features, we enhance your API security with Azure Active Directory, OAuth, or social sign-on. Our strategy incorporates API protection using keys, tokens, and IP filtering. We manage API traffic and quotas by deploying API gateways across Azure, other clouds, and on-premises environments. We also improve API performance through response caching, which optimizes latency. To accelerate app development, we can transform legacy services into REST-based APIs, allowing front- and back-end teams to work independently. We provide a customizable Azure developer portal for all your APIs to foster collaboration among internal teams, external partners, and customers. Additionally, we integrate your API with your preferred version control system to streamline code changes.

Successfully build APIs of high performance

We successfully build APIs of high performance and security for any industry and right for your specific requirements. Our developers use modern methods to provide data processing in different programming languages. We focus on your needs and always meet customers’ expectations.

Contact us today to get professional IT consultation on your API development/integration idea.

Our API specialists, who have extensive experience in providing API development and integration services, using C, C++, Java, Python, and PHP, create powerful, secure, and easily maintainable APIs.

API Integration Services

Integrating an API can help quickly and cost-effectively develop products or implement new features, and seamlessly interface with other systems. API integration means setting smooth communication between diverse software components, technologies, and programs: medical software integration, integration with Google, Yahoo!, PayPal, Amazon, Skype, Facebook and Twitter; integration with JS, XML, RESTful APIs; integration with Oracle web services and much more. With our help, you can implement or connect internal and external API services for mobile, platform, or web apps.

Healthcare API Integration & Development

Our API integration and development services, along with software development for healthcare, aid in powering a new wave of healthcare applications, serving as a reliable bridge for providers, payers, and partners. We integrate APIs that ensure seamless access to patient information, promoting interoperability between data sources. This allows for real-time access to clinical documents, leading to improved risk management, better HEDIS scores, and accurate, quick adjudication of payments. We can also integrate or develop APIs that simplify transactions, handling eligibility verification, claims submission, and payment processes efficiently.

SaaS API Integration & Development

With expertise in SaaS software development, we particularly specialize in creating custom SaaS API integration solutions with real-time data-sharing capabilities that can listen to third-party apps for specific events. We can also develop a unified platform for API management to easily expose data to and from SaaS applications. Additionally, we build API-based SaaS software that enables end-users to integrate your software with other apps. Out-of-the-box connectors, integration templates, and a drag-and-drop environment make SaaS connectivity quick and easy.

IoT Integration Services

Our IoT integration services are designed to seamlessly connect your IoT devices, data, platforms, and applications with your existing IT assets. We understand the complexity of integrating new IoT components with legacy systems, business applications, mobile platforms, and SaaS. Our service offering includes creating a cohesive ecosystem where all these elements work harmoniously, enabling the successful implementation of end-to-end IoT business solutions. As part of a rapidly growing IoT integration market, we provide the capabilities you need to ensure smooth, efficient, and effective IoT project implementation.

Custom API integration

A custom API is necessary when a suitable ready-made API is not available or does not fit your needs or you want to integrate your application with an interface of an existing API. A custom API allows for sharing your product data and capabilities. Our expert developers will bridge the gap between your platform or app and the critical information and data you need to succeed. With our secure API communication, you can rest easy knowing your business is in good hands. We will help you find, develop, or review the API services for your unique needs. We're experts in various API services including REST and GraphQL and we've got experience in programming high-speed, large-scale API projects.

E-commerce API Integration

Our API experts help you synchronize your e-commerce services with inventory management systems, product feeds, order management, international shipping, gift card loyalty services, ERP/CRM systems, cart management and more. You can connect your app to external services, take orders with custom payment gateways, share sales data with your accounting system, send orders to your warehouse for fulfillment, provide chat and support tickets, track deliveries in real-time, integrate with Google and Apple services, and synchronize your retail POS customers. We can help expand your e-commerce capabilities to support platforms such as Shopify, Magento, and more.

CRM API integration

By utilizing a CRM API, sync all information into one central location, eliminating issues of multiple data sources. Get the ability to manage leads directly from your email, like Gmail or Outlook, for more effective email marketing and to not miss important notifications. Syncing your web-based calendar with your CRM ensures that you stay up-to-date and never schedule a call with a sales prospect in your CRM and forget to add it to your calendar. Connect platforms like Facebook, Instagram, Twitter, and LinkedIn to your CRM. Sync data gained from surveys (like SurveyMonkey and Typeform) with the contact data in your CRM. Integrate your CRM with communication platforms like Slack, Microsoft Teams, Zoom.

ERP API integration

APIs can greatly enhance the functionality of your ERP system, maximizing the return on your ERP investment. Third-party vendors provide APIs that enrich ERP data in several ways. For example, they enable communication with mobile applications, integrate with e-commerce platforms to automate inventory management, order tracking, shipping, and more. They also ensure accurate and synchronized inventory data across all sales channels, allow automatic import of orders and the insertion of shipping tracking information into e-commerce stores. Plus, they support dashboard visualizations for business intelligence, analytics, and reporting, offering a comprehensive view of business operations and resource allocation.

Logistics API integration

For third-party logistics companies, it's vital to ensure seamless information exchange between shippers and carriers, as well as facilitate connections with cloud providers. APIs like JSON or XML enable smooth integration with ERPs, TMS, WMS, and financial systems. Replace the EDI-based load-tender-to-invoice process with real-time APIs, get real-time updates on location and route tracking through connections with electronic logging device aggregators and visibility providers. Moreover, you can access accurate spot rate information, automate freight matching, determine the most cost-effective routing options, and integrate back-end applications, such as SaaS and legacy systems, into your supply chain processes.

Payment API integration

API-based payment integration can greatly enhance the checkout experience for both merchants and customers. Payment APIs enable businesses to seamlessly incorporate payment processing capabilities into their existing software and mobile apps. With payment APIs or payment API gateways, eCommerce and retail vendors can issue refunds for online payments, enable recurring payments for subscription-based or SaaS businesses, integrate various local and global payment options, track orders and access real-time data on transactions, and easily reach customers in international markets.

API integration testing

Our expert team will execute thorough API testing, harnessing the power of our automated software testing services to confirm aspects like functionality, performance, reliability, and security. We will adapt our automated testing methods to cater to your specific needs, ensuring that your APIs are strong and ready for real-world challenges. Our versatile API testing solutions easily merge with your current CI/CD pipeline and development tools, facilitating smooth cooperation and quick deployment, simplifying the task of creating and implementing high-quality APIs. testing solutions

Why Choose Belitsoft API Development Company


Our API specialists, who have extensive experience in providing API development and integration services, using C, C++, Java, Python, and PHP, create powerful, secure, and easily maintainable APIs. API masters from a business software development company Belitsoft has technical expertise in working with the most popular APIs such as Google APIs, Yahoo APIs, Social Media APIs (Twitter, Facebook, LinkedIn, Instagram), Marketplaces APIs (eBay), other APIs, and mashups.


Hire API developers from Belitsoft for significant cost savings. Why? First, the overall cost of your project will be far lower than developing the same project in the USA. Second, our skilled developers, with their hands-on experience in utilizing the latest technologies and adhering to best practices, build secure and high-performance APIs. This approach reduces the need for extensive support and maintenance, saving you both time and money.


We successfully build APIs of high performance and security for any industry and right for your specific requirements. Our developers use the SOAP / REST API methods for data processing in different programming languages. We document all the APIs using tools like Swagger for improved usability.

Frequently Asked Questions

API (Application Programming Interface) is a set of certain protocols, specific standards, and tools, which are used by a programmer to integrate different applications. APIs enable access to another app or platform. Due to APIs, applications can interact with each other. Use of API not just simplifies programming, but it also enhances user experience, increasing the popularity of your application and facilitating user’s control over different applications. Today, all advanced applications are being improved by specialized APIs.

There are different types of APIs. They vary depending on what programming language is used – procedural, object-oriented etc.: for applications (Google Maps API, Facebook API, Twitter APIs, LinkedIn API); for a web-based system or a website (Amazon, eBay); for operating systems (POSIX is for Linux and Berkeley Software Distribution, Microsoft Windows API); for a database system; for computer hardware; for a software library.

Also, there three main policies for releasing APIs: private (for internal use), partner (for business partnerships), and public (for public use).

As for API’s design, it aims at providing only those tools, which end users expect. The principle of information hiding is used here not to bother users with unnecessary for them complex implementation details.

Each API goes with documentation where all the information on what the services API offers and how to use them is given. API documentation is also necessary for developers because it includes the description of classes and methods, typical usage scenarios, code snippets etc.

Integration with third-party apps, which provide real-time functionality or manage computations, without needing to write your own complex algorithms (this is true for e-commerce, finance and other industries).

Empower your lead generation or CRM apps with social insights (by matching email addresses against social media profiles).

Integration web/mobile apps with a cloud storage of files.

Integration mobile apps with a remote backend to push files and retrieve data.


EHR CRM Integration and Medical BI Implementation for a Healthcare Network
EHR CRM Integration and Medical BI Implementation for a Healthcare Network
The significance of this achievement has garnered the attention of the US government, indicating an intent to deploy the software on a national scale. This unique integration allows for pulling data from EHRs, visualizing them in a convenient and simple way, then allows managing the necessary data to create health programs, assigning individuals to them, and returning ready-to-use medical plans to the EHRs of health organizations.
API Integration for Digital Transformation of a Freight Management Company
API Integration for Digital Transformation of a Freight Management Company
Our Client, a US-based freight management company, needed a custom core business app to optimize their workflows.
100+ API Integrations for Data Security Management Company
100+ API Integrations for Data Security Management Company
Our Client, the US data management company that sells software for managing sensitive and private data in compliance with regulatory laws, needed skilled developers for building API integrations to the custom software.
Mobile Applications for a Sports IoT devices Manufacturer
API to connect IOS and Android Apps to backend services (AWS database/IoT)
Our client is a successful manufacturer of an innovative sports IoT device named Sportstation. We developed IOS and Android applications which can communicate with it. We also made Integration with several third-party systems, e.g. with the system of the children’s football camp of Real Madrid.
Instant Payment App Development for Mobile Banking
Open Banking API Gateway Platform for a fintech startup
Belitsoft was contacted by the founders of a startup from one of the EU Member States. They wanted to create a mobile app that would support SEPA Instant Credit Transfer (SCT Inst) scheme to make real-time payments.
Customization of ready-to-use InsurTech Software for individual needs of particular insurance organizations
Microservice-based APIs for a large product company
Our client is a global insurance custom software development company (1.6M+ EUR in revenues in 2016) with the teams in the USA, the UK, Estonia, Latvia, Lithuania, and Poland. The Client asked us to enlarge his team with dedicated software developers to speed up the process of maintaining his system and adding new complex custom features to it.
Sports Team Communication App Development
Full Stack API Development
A convenient platform for sports clubs, amateurs, and professionals.

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