API integrations in business — how automation connects systems and saves working hours

An API (Application Programming Interface) is the way two software systems communicate. When you fill in a form on Aliansa.rs and receive a quote from three insurers in 20 minutes — that is an API. When your online store automatically synchronises stock levels with warehouse software — that is an API. Without API integrations, data is entered manually, errors multiply, and working hours are wasted.

The most common business cases in Serbia: payment systems (NestPay, Corvus, Stripe for international transactions), email marketing (Mailchimp, Brevo — automatically adding customers from the site), CRM systems (Salesforce, HubSpot, domestic systems), ERP integrations (orders from the site directly into accounting), and industry APIs (insurance, logistics, banking).

What an API integration looks like from the inside: your site sends an HTTP request with data to an external system, the external system processes the request and returns a response (often in JSON format), your site displays the result to the user. All of this takes milliseconds. The complexity is not in the principle but in the details: authentication, error handling, rate limiting, and testing edge cases.

The cost of a custom API integration depends on complexity: a simple integration (e.g. a contact form into a CRM) from €500–1,500, moderately complex (payment system, email automation) from €1,500–4,000, complex (multi-system like Aliansa with three insurers) from €5,000 upward. Timeline: 1–6 weeks depending on the API provider's documentation and the number of systems.

When custom is better than off-the-shelf: when a ready-made integration (Zapier, Make) does not support your domestic system, when specific business logic is needed, or when transaction volume makes SaaS costs more expensive than development. Feather Studio has built API integrations for insurance, e-commerce, and B2B systems — see the Aliansa.rs case study or contact us for an assessment.