API

An API (short for "Application Programming Interface") is a set of rules that lets two programs communicate with each other without needing to know how the other one is built inside. It works like a contract: the system that offers the API publishes which requests it accepts and which responses it returns, and any other system can consume it by following that contract.

The classic analogy is the waiter in a restaurant: you do not go into the kitchen or know how each dish is prepared; you order from the menu through the waiter and they bring you the result. The API is that intermediary: it translates your request, takes it to the right system and returns the response in a predictable format. That is why it is the building block of any integration between modern applications.

In the Salesforce world, APIs are what let the platform talk to your ERP, your e-commerce store, WhatsApp or an invoicing system, instead of remaining a data island. Connecting those systems through APIs is part of the implementation work that Salesforce covers, where clean integration between platforms avoids duplicate data entry and intermediate spreadsheets.

How an API works in practice

An API exposes a set of endpoints (addresses you send a request to) and, for each one, defines the method, the input parameters and the response format. Most business APIs today are REST: they travel over HTTP, use verbs such as GET (read), POST (create), PUT/PATCH (update) and DELETE (delete), and return data in JSON. The system that makes the request is called the client and the one that responds is the server; only the contract travels between them, never the internal code.

A concrete example in Argentina: a consumer goods company takes orders through its online store and needs each sale to appear as an Opportunity in its CRM and to trigger electronic invoicing with ARCA (Argentina's federal tax agency, formerly AFIP). Instead of an employee copying data by hand three times, the store calls the CRM's API to create the record, and the CRM calls the tax system's API to issue the invoice. Everything happens in seconds and without human intervention. That chain of calls is what supports the idea of a single source of truth: data is entered once and flows on its own.

Why it matters for the business

A well-designed API is the difference between systems that talk to each other and systems that live in isolation. Its concrete benefits:

• It eliminates duplicate data entry: data moves from one system to another without being retyped, which reduces errors and hours of manual work.
• It enables automation: without an API there is no way for one process to trigger another across different platforms (for example, a confirmed payment updating stock).
• It lets you scale without rebuilding everything: you can add a new tool by connecting it to the existing ecosystem instead of migrating everything to a single piece of software.
• It provides access control: the API exposes only what is needed and requires authentication, so third parties use your data without seeing your entire database.

Authentication is usually handled with API keys (a secret token that identifies the caller) or, in more secure scenarios, with OAuth, which delegates permission without sharing passwords. And to avoid overloading the server, almost all APIs apply rate limiting: a cap on how many calls are accepted per minute.

API vs webhook: two ways to connect systems

This is the most common confusion. A traditional API works by request: your system asks ("are there any new orders?") and the other one answers. A webhook reverses the logic: the system notifies you on its own when something happens, without anyone asking. It is worth being clear on the difference before designing an integration.

In practice they are almost always used together: the webhook signals that something happened and the API is used to fetch the full details or execute the action.

Common mistakes when working with APIs

• Ignoring the platform's limits: in Salesforce, for example, governor limits restrict how many calls can be made; a poorly designed integration exhausts them and stalls the system.
• Not handling errors: an API can respond that a record does not exist or that the server is down, and the integration has to account for those cases instead of assuming it always works.
• Hardcoding keys: leaving an API key written in the code and pushing it to a repository is one of the most frequent security leaks.
• Treating the API as magic: an API does not clean or transform data on its own; if the source data is dirty, it arrives dirty at the destination.

The first step toward designing integrations that scale is understanding what an API is. It is not an isolated technical detail: it is the foundation on which any software ecosystem that works as a whole is built.