# What is an API?

> What an API is: the contract that lets two pieces of software exchange data. Includes a worked example for a Quebec service SME and common mistakes.

Updated on October 15, 2026 · https://app.pilotiko.com/en/glossary/api

An API, or application programming interface, is a set of features and rules that a piece of software exposes so another program can interact with it automatically, without going through a person's screen. It works like a contract: you know what you can ask for, in what format, and what you will get back.

## In short
- APIs are for programs, not people: they replace manual re-entry.
- A precise request and a predictable reply make up the contract.
- You call an API; a webhook calls you.
- Every access should be scoped, identified and revocable.

## What does API actually mean?

MDN Web Docs, the reference documentation used by web developers, describes an API as a set of features and rules inside a piece of software that let other software interact with it, rather than through a user interface. MDN frames it as a simple contract between the software offering it and third-party software or hardware [1].

Browsers expose APIs for things like the camera or geolocation. Between businesses, an API is what lets a booking page read open slots from a calendar, or lets an accounting package receive invoices from a field-service tool [1].

## How does an API exchange work, step by step?

1. **The client program identifies itself** — It presents a key or token proving it may call the API. When it acts on behalf of a person, that token often comes from [OAuth](https://app.pilotiko.com/en/glossary/oauth).
2. **It sends a precise request** — For example: give me the March 12 appointments for the Saint-Jérôme crew.
3. **The software checks and answers** — It returns the data in an agreed format, often JSON, or a clear error message.
4. **The client uses the answer** — It shows the data, copies it into another tool or triggers a next step.

## API or webhook: which one do you need?

With an API, your program asks the question when it chooses. To find out whether something changed, it must keep checking, which GitHub's documentation calls polling. A [webhook](https://app.pilotiko.com/en/glossary/webhook) flips that around: the source system sends the data to you as soon as an event happens [2].

| Question | API call | Webhook |
|---|---|---|
| Who starts the exchange? | The program asking | The system where the event happens |
| When does data move? | When you ask | As soon as the event occurs |
| Typical use | Read a list, create a record, look up a customer | Get told about a payment or a new booking |
| Main risk | Asking too often for nothing | Accepting a fake message if the sender is not verified |

## How much time can an API connection save?

**Example: a 5-technician pest control company in Quebec City**

Assumption: every completed work order is retyped into the accounting software to produce the invoice. An API link would send the hours and products used directly.

- Completed work orders per week : 60
- Minutes of retyping per order : 4
- Weekly data entry (60 × 4 min) : 240 min, or 4 h
- Retyping errors found per month (assumption) : 6
- **= About 4 hours of weekly data entry that an API link could remove, provided both tools offer compatible APIs.**

## What mistakes should you avoid with APIs?

- Pasting an API key into an email or a shared document: whoever holds it can act as you.
- Giving an integration full rights when it only needs to read the calendar.
- Building an [automated process](https://app.pilotiko.com/en/glossary/process-automation) with no plan for what happens when the API returns an error.
- Assuming every [SaaS](https://app.pilotiko.com/en/glossary/saas) product has an API: NIST mentions access through a program interface as one option, not a requirement [3].
- Leaving a former vendor's access active after the contract ends.

## Does Pilotiko offer an API?

Pilotiko's capability register does not list a public API for customers, so we make no such claim here. If a specific integration matters to you, ask before your trial. Pilotiko's [AI agents](https://app.pilotiko.com/en/glossary/ai-agent) work from data already in the application, and anything that sends something out waits for a person's approval.

## Frequently asked questions

### Do I need to be a programmer to use an API?

To build one or call it directly, yes, you need some programming skills. Many automation tools, however, offer ready-made connectors that use the API for you. You then map the fields without writing code.

### Are APIs secure?

They are as secure as the way access is managed. Use a separate key per integration, limit rights to what is needed and revoke keys you no longer use. Never send a key by email.

### What is the difference between an API and an integration?

The API is the door a piece of software offers. The integration is the actual connection between two tools, built on one or more APIs. A product can have an API with no integration in place yet.

### What is a REST API?

It is a common style of web API in which each resource, such as a customer or an appointment, has its own address and standard HTTP methods are used to read or change it. For a small business, what matters most is clear, current documentation.

### Can an API cost extra?

Yes. Some vendors reserve API access for higher plans or cap the number of calls per day. Check those limits before building a process that depends on them.

## Sources

1. MDN Web Docs, « API (glossary) », https://developer.mozilla.org/en-US/docs/Glossary/API (accessed on 2026-10-15)
2. GitHub Docs, « About webhooks », https://docs.github.com/en/webhooks/about-webhooks (accessed on 2026-10-15)
3. NIST, « SP 800-145, The NIST Definition of Cloud Computing », https://csrc.nist.gov/pubs/sp/800/145/final (accessed on 2026-10-15)