Automation and systems integrations pay significant role in business efficiency and streamlining processes. One of the most powerful tool to use is REST API—a cutting-edge interface ensuring secure and efficient data exchange between apps. How it is leveraged every day to streamline processes? Let’s break it down.
In this article:
What is REST API and how it works?
REST API (Representational State Transfer Application Programming Interface) is one of the most widely used methods for enabling communication between IT systems. In simple terms, it allows different applications to “talk” to each other and exchange data quickly, securely, and in a standardized way—usually via the HTTPS protocol.
At its core, REST API relies on a set of straightforward methods:
- GET – retrieve data
- POST – add new data
- PUT – update existing data
- DELETE – remove data
These operations make it possible to manage information across systems without unnecessary complexity.
The biggest advantage of REST API is its lightweight design, platform independence, and ease of integration. This makes it ideal for environments where multiple tools need to work together—for example:
- Integrating ERP software with e-government services
- Connecting an accounting system with a document workflow platform
- Linking a mobile app to a central database
REST API typically uses JSON or XML for data exchange, which ensures compatibility and simplicity for developers and system integrators. By implementing REST API, companies can automate information flow between systems, eliminate manual tasks, accelerate every day processes, from customer service and document management to reporting and analytics.
Who may leverage REST API?
REST API is a solution that works for large enterprises as well as medium and small businesses focused on automation, system integration, and digital process development. It’s an interface that connects different applications, internal systems, and external tools in a fast, secure, and standardized way. Who benefits most from REST API?
- Companies with distributed IT infrastructure
Businesses that need smooth data flow between multiple systems such as ERP, CRM, DMS, or BI. - Organizations processing large volumes of data and documents
Where automation and eliminating manual data entry are key to efficiency. - Businesses developing their own applications
REST API makes it easy to integrate external functionalities like online payments, logistics, e-commerce, or invoice management. - Entities required to integrate with government systems
For example, KSeF, PUE ZUS, or ePUAP—where API is the only communication method.
REST API is a tool for companies that want to stay flexible, fast, and ready for further digital transformation. It enables seamless integration, accelerates workflows, and opens the door to innovation.
How a company of today will benefit from REST API?
In today’s world of digitisation and automation, the top priority for businesses is boosting operational efficiency. REST API fits perfectly into this vision, enabling seamless integration between the various systems and applications used within an organisation.
With REST API, data can flow in real time, eliminating the need for manual copying or juggling multiple disconnected tools.
By connecting systems, REST API accelerates workflows, reduces the risk of errors, and improves transparency.
Example: Integrating a document management system with accounting software allows invoices to be transferred automatically, statuses updated, and payments tracked—all without human intervention. This frees teams to focus on strategic tasks instead of repetitive manual work.
REST API gives companies the flexibility to:
- Implement new solutions quickly
- Expand existing systems with additional features
- Integrate with external services such as online banking, e-commerce platforms, or public administration systems (e.g., KSeF).
This integration power makes modern businesses more resilient to change and better equipped to adapt to evolving market demands.
REST API for digital workflow and integration with KSeF API 2.0
REST API is widely used in digital document workflows, especially in the context of data exchange with external public administration systems.
An example is the integration with API 2.0 of the National e-Invoicing System (KSeF), which allows companies to automate the process of sending, receiving and verifying structured invoices. By leveraging REST API, DMS or ERP systems can connect directly to the KSeF platform, which translates into faster document circulation, elimination of human error and real- time control over invoicing processes.
This type of integration is crucial for companies that want to operate efficiently and in accordance with regulations in the new reality of e-invoicing.
Security and control – how to implement API?
Wdrożenie REST API w firmie wiąże się z wieloma korzyściami, ale wymaga również przemyślanego podejścia do kwestii bezpieczeństwa i zarządzania dostępem. Źle zaimplementowane API może narazić organizację na wycieki danych, ataki z zewnątrz lub niekontrolowany dostęp do kluczowych zasobów. Dlatego, tak ważne jest, aby proces integracji przebiegał zgodnie z najlepszymi praktykami.
Podstawą jest uwierzytelnianie i autoryzacja – każda aplikacja lub użytkownik korzystający z API powinien być zidentyfikowany i posiadać odpowiednie uprawnienia. Powszechnie stosowanym standardem jest OAuth 2.0, który umożliwia bezpieczne udostępnianie zasobów bez konieczności przekazywania danych logowania.
Kolejnym krokiem jest szyfrowanie transmisji danych – połączenia API powinny odbywać się wyłącznie za pośrednictwem protokołu HTTPS, co chroni dane przed przechwyceniem. Dodatkowo warto zadbać o zabezpieczenie przed typowymi atakami, takimi jak SQL injection, cross-site scripting (XSS) czy brute force, np. przez wprowadzenie limitów żądań (rate limiting) i monitorowanie ruchu.
Ważnym aspektem jest także dokumentacja i wersjonowanie API. Jasno opisana struktura endpointów, parametrów i odpowiedzi to nie tylko wygoda dla programistów, ale też element kontroli nad tym, jak wykorzystywane są dane. Dzięki wersjonowaniu można wprowadzać zmiany bez ryzyka przerwania działania istniejących integracji.
Na końcu – logowanie i monitoring. Rejestrowanie operacji i alertowanie o nietypowej aktywności pozwala szybko reagować na potencjalne incydenty i zapewnia zgodność z regulacjami, np. RODO. Zautomatyzowane mechanizmy audytu umożliwiają też ocenę wydajności i bezpieczeństwa API w czasie rzeczywistym.
Dobrze zaprojektowane REST API to nie tylko funkcjonalność, ale również solidne zabezpieczenia, które chronią dane i procesy firmy.
REST API in digital strategy – key factors
Introducing REST API into your digitalisation strategy is one of the important steps toward process automation and and improving organizational efficiency. However, for the integration to be successful, it is necessary to plan the entire process carefully and take into account key technical and organisational aspects.
The first step is to define the business objectives that the API should support. Ask yourself the following questions: Which systems need to communicate? What data is to be exchanged? Which processes should be automated? Such an analysis allows you to determine the scope of integration and plan an API architecture that will be scalable and aligned with the organisational goals.
Next, select a trusted system or platform provider that offers well-documented REST APIs. Clear documentation, readable request and response structures, stable endpoints, and technical support are elements that facilitate implementation and ongoing maintenance.
From an IT perspective, testing and phased implementation are key. Use sandbox environment to avoid errors in production environment. Follow best programming practices: apply REST standards, implement proper error handling, and enforce security policies.
The involvement of the business team should not be forgotten either – an API is only a tool, and its real value comes from integration with specific processes: invoicing, reporting, document management or order flow.
Therefore, it is important that API-based digitisation is part of a broader digital transformation strategy, supported by all departments of the organisation.
