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APIs and integrations

| Article: 3 min read | Business systems

An API (application programming interface) is a set of rules and capabilities inside a program through which another program can interact with it, as opposed to a human interface. It is a "contract" between the program that offers the API and third-party programs or devices (MDN). An integration is a connection between two systems through such a contract, so that they exchange data without manual transfer.

In plain words

When you search for a Nova Poshta branch on a store's website, the site doesn't dig into the carrier's database. It sends a request to a special "window" (the API) and gets an answer: a list of cities and branches. In the same way, the site can pass an order to a CRM, and an accounting system can send back stock levels.

An integration is the work that uses an API: someone configures which data to send, when, and in which direction.

How systems exchange data

There are several ways. All of them occur in a store.

  • Request by request (API). One system itself calls another: "give me the stock", "create a waybill". The rules of the request are described in the API documentation. There are standards for describing APIs: the OpenAPI specification is at version 3.2.1 of 10 September 2026 (OpenAPI Initiative).
  • Webhook. A system itself notifies another when something has happened: an order was paid, a status changed. According to Wikipedia, these are "user-defined HTTP callbacks": on an event the source sends a request to an address you set, and the receiver doesn't have to poll the system constantly (Wikipedia, Webhook).
  • Files. Exporting a spreadsheet or XML, as in product feeds. Simple, but slow and without instant updates.
  • Ready-made module or connector. The vendor has already built a link between two popular services; you just switch it on and enter a key.

Why a store needs it

Without integrations, data between systems is moved by hand: orders from the site to the CRM, stock to the accounting system, waybills to the delivery service. This is slow and causes errors.

Typical links in a store:

When you need it

When you notice that someone moves data between systems every day, or that stock on the site diverges from the warehouse.

When it is too early

When there are two or three systems and the exchange is a few orders a day. Then a ready-made module, or even manual transfer, is enough. Don't build a complex link for an order you don't yet need.

Security and reliability

  • API keys are "passwords" between systems. Don't send them around in messengers and don't publish them.
  • Webhooks should be verified: Wikipedia lists common ways to authenticate incoming requests (a shared secret, a digital signature, an HMAC signature in a header) and checking the request time against replays (Wikipedia, Webhook).
  • What happens on failure: the integration should retry sending and show errors, otherwise an order "hangs" unnoticed.
  • Who is responsible: the service vendor or your integrator. It is worth knowing before launch.
  • Customers' personal data moving between systems falls under the personal data protection law. This is not legal advice.

Common mistakes

  • A one-way integration while data changes in both systems: discrepancies.
  • No single order key across systems.
  • Nobody monitors exchange errors.
  • A closed system with no API: later nothing can be connected to it. Before choosing a service, ask whether there is an open API and data export (SaaS).

FAQ

What is an API in plain words? A way for one program to ask another for data or an action under rules described in advance.

What is an integration in an online store? An automatic connection of systems: the site passes an order to the CRM or accounting, the delivery service returns a status.

How is a webhook different from an API? With an API, you request the data yourself. With a webhook, the system notifies you when something has happened.

Do you need a programmer for an integration? For a ready-made module, usually not; for a non-standard link, yes. It depends on the systems you are connecting.

Sources

For the specific capabilities of the Nova Poshta API, see its documentation (developers.novaposhta.ua).

There is no fresh data on how Ukrainian stores integrate their systems.

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