Adyen is a global payments platform that provides APIs and infrastructure to accept, process, and manage payments across multiple channels (online, in-person, and mobile).

From a developer perspective, Adyen is not just a payment gateway—it combines:

Payment processing
Risk management
Authentication (e.g., 3D Secure)
Payment method orchestration
Reporting and lifecycle events (via webhooks)

All of this is exposed through a set of APIs and client-side components.

Core Concept

At its core, integrating Adyen means:

Collecting payment details (securely, usually via Adyen UI components or hosted solutions)
Sending a payment request to Adyen’s API
Handling the response (synchronous or asynchronous)
Reacting to lifecycle events via webhooks (e.g., payment captured, failed, refunded)

Key Building Blocks

When working with Adyen, you will interact with the following core elements:

1. Payments API

Used to create and manage payments.

Example request (simplified):

POST /payments

{
  "amount": {
    "currency": "EUR",
    "value": 1000
  },
  "reference": "ORDER-12345",
  "paymentMethod": {
    "type": "scheme",
    "number": "4111111111111111",
    "expiryMonth": "03",
    "expiryYear": "2030",
    "cvc": "737"
  },
  "returnUrl": "https://yourapp.com/redirect"
}

This request:

Creates a payment
Triggers authentication if required (e.g., 3DS)
Returns a result that determines the next step

2. Client-Side Components (Drop-in / Components)

Adyen provides prebuilt UI elements to securely collect payment details.

Instead of handling sensitive card data yourself, you typically use:

Drop-in → all-in-one UI
Components → individual payment method UIs

This helps:

Reduce PCI scope
Ensure compliance
Speed up integration

3. Sessions vs Advanced Flow

Adyen supports two main integration patterns:

Sessions Flow (recommended)
Backend creates a session → frontend handles most of the flow
Advanced Flow
Full control over /payments and /payments/details calls

Your choice affects:

Complexity
Control over UX
Backend responsibility

4. Webhooks (Notifications)

Not all payment outcomes are immediate.

Adyen sends webhook events to notify your system about:

Authorizations
Captures
Failures
Refunds

Example event:

{
  "eventCode": "AUTHORISATION",
  "success": "true",
  "pspReference": "123456789",
  "merchantReference": "ORDER-12345"
}

Your system must process these events to:

Update order status
Trigger business logic

Payment Flow (High-Level)

A typical online payment flow looks like this:

Frontend collects payment details (Drop-in / Components)
Backend sends payment request to Adyen
Adyen returns:
- Authorised → success
- Refused → failure
- RedirectShopper → requires action (e.g., 3DS)
Customer completes any required actions
Adyen sends final status via webhook