Adyen

The Adyen SDK for .NET provides access to the Adyen REST APIs from .NET applications.

The A2A payments API provides endpoints for A2A payment flows, enabling issuers to facilitate direct payments through Adyen for users with an Adyen business account.

With these endpoints, you can:

• Retrieve payment details: Retrieve transaction information for specific payments.
• Confirm payments: Confirm payments with Strong Customer Authentication (SCA).
• Cancel payments: Cancel pending transactions.

Authentication

Each request made to the A2A Payments API must be signed with an API key. Generate an API key in your Customer Area.

To connect to the API, add an X-API-Key header with the API key as the value, for example:

curl
-H "Content-Type: application/json" \
-H "X-API-Key: YOUR_API_KEY" \
...

Roles and permissions

To use the A2A Payments API, your API credential must have the following roles:

• Role for A2A Issuer payments - API

Reach out to your Adyen contact to set up these roles.

Going live

When going live, generate an API key in your live Customer Area. You can then use the API key to send requests to https://balanceplatform-api-live.adyen.com/a2aissuer-api/v{version}/payments.

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Installation

Add the .NET SDK as a project reference into your solution:

dotnet add reference <path-to-sdk>/Adyen.csproj

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Quick Start

Dependency Injection

Register the client with IServiceCollection and resolve it from the container. The HttpClient is managed by IHttpClientFactory. Configure the client's behavior through AdyenClientOptions.

services.AddAdyenClient(options =>
    {
        options.BasicAuth =
            new BasicAuthCredentials
            {
                Username = "YOUR_USERNAME",
                Password = "YOUR_PASSWORD",
            };
        options.ApiKeyAuth = "YOUR_API_KEY";
        options.ClientKey = "YOUR_API_KEY";
        options.Environment = ServerEnvironment.Production;
        // TODO: configure more client options here
    });

Direct Instantiation

Create the client by passing an HttpClient you manage yourself. Configure the client's behavior through AdyenClientOptions.

var httpClient = new HttpClient();
// TODO: configure more client options here
var options =
    new AdyenClientOptions
    {
        BasicAuth = new BasicAuthCredentials
        {
            Username = "YOUR_USERNAME",
            Password = "YOUR_PASSWORD",
        },
        ApiKeyAuth = "YOUR_API_KEY",
        ClientKey = "YOUR_API_KEY",
        Environment = ServerEnvironment.Production,
    };
var client = new AdyenClient(httpClient, options);

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Usage

For code examples and error responses, see API Reference.

Best Practices

Tip

Use a single AdyenClient instance for the lifetime of your application and reuse it across all requests. Creating a new instance per request might exhaust the connection pool.

License

This SDK is distributed under the MIT License.

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Support

Refer to the API reference for detailed information on available operations with code samples.

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