C# and .NET SDK for KYC, AML and Transactions

The official Didit library for C# and .NET. It targets .NET 8 and .NET Standard 2.0, and every API method is async. On .NET Framework, use C# 11 or later. See the server SDKs overview for what every SDK shares.

Install

dotnet add package Didit

For ASP.NET Core dependency injection, also add Didit.Extensions.DependencyInjection and register the client with services.AddDidit(). The packages are Didit and Didit.Extensions.DependencyInjection on NuGet. Their source and changelog are in didit-protocol/sdk-dotnet on GitHub.

Configure the client

new DiditClient() reads DIDIT_API_KEY from the environment. Pass DiditClientOptions to override it, or to set the organization and application ids that application-scoped calls (cases, networks, regulatory reports) need. Create one client and reuse it.

using System;
using Didit;

using var client = new DiditClient(new DiditClientOptions
{
    ApiKey = Environment.GetEnvironmentVariable("DIDIT_API_KEY"),
    OrganizationId = Environment.GetEnvironmentVariable("DIDIT_ORGANIZATION_ID"),
    ApplicationId = Environment.GetEnvironmentVariable("DIDIT_APPLICATION_ID"),
    Timeout = TimeSpan.FromSeconds(30),
    MaxRetries = 2,
});

// Options for a single call.
var decision = await client.Sessions.RetrieveDecisionAsync(
    "11111111-2222-3333-4444-555555555555",
    requestOptions: new RequestOptions { Timeout = TimeSpan.FromSeconds(5), MaxRetries = 0 });
Console.WriteLine(decision.Status);

Required request properties are required, so a missing one fails to compile. Optional ones you leave unset are not sent.

Create a session

Create a verification session for a workflow and send your user to its URL.

using System;
using Didit;

using var client = new DiditClient();

var session = await client.Sessions.CreateAsync(new SessionsCreateParams
{
    WorkflowId = "11111111-2222-3333-4444-555555555555",
    VendorData = "user-123",
    Callback = "https://example.com/verification/done",
});
Console.WriteLine(session.Url);

Read the decision

When the user finishes (or when the webhook arrives), read the decision. Every feature result is a list with one entry per workflow node.

using System;
using Didit;

using var client = new DiditClient();

var decision = await client.Sessions.RetrieveDecisionAsync("11111111-2222-3333-4444-555555555555");
Console.WriteLine(decision.Status);
foreach (var verification in decision.IdVerifications ?? Array.Empty<SessionDecisionIdVerifications>())
{
    Console.WriteLine(verification.Status);
}

Verify a webhook

Pass the raw body, exactly as received, and a way to read the request headers. DiditWebhooks.Verify throws WebhookVerificationException for anything that is not a valid, fresh delivery, and returns a typed event otherwise.

using System;
using Didit;

var secret = Environment.GetEnvironmentVariable("DIDIT_WEBHOOK_SECRET") ?? "";

int HandleWebhook(string rawBody, Func<string, string?> header)
{
    try
    {
        var evt = DiditWebhooks.Verify(rawBody, header, secret);
        if (evt is SessionStatusUpdatedEvent updated)
        {
            Console.WriteLine($"{updated.SessionId} {updated.Status}");
        }
        return 200;
    }
    catch (WebhookVerificationException error)
    {
        Console.WriteLine($"rejected: {error.Reason}");
        return 400;
    }
}

In an ASP.NET Core minimal API, read the body with a StreamReader and pass name => request.Headers[name].FirstOrDefault(). While you rotate the secret, pass both: new[] { newSecret, oldSecret }. See Webhooks for the events and the signature scheme.

Screen a transaction

Submit a payment, withdrawal or crypto transfer to transaction monitoring; the response carries its status and risk score.

using System;
using Didit;

using var client = new DiditClient();

var transaction = await client.Transactions.CreateAsync(new TransactionsCreateParams
{
    TransactionId = "txn-1001",
    TransactionCategory = "finance",
    TransactionDetails = new()
    {
        Direction = "outbound",
        Amount = 1500,
        Currency = "EUR",
    },
    Subject = new()
    {
        EntityType = "individual",
        VendorData = "user-123",
        FullName = "Maria Garcia",
    },
});
Console.WriteLine($"{transaction.Status} {transaction.Score}");

Verify Authentication tokens

Authentication checks the access tokens your Authentication issuer signs, in your backend, without calling Didit for each request. It also exchanges codes, refreshes tokens, checks and revokes sessions, and runs step-ups.

Token verification makes the checks in Verify a token on your server, against your application’s issuer and signing keys.

using System;
using System.Threading.Tasks;
using Didit;

// The publishable key (pk_live_... or pk_test_...) carries your issuer URL.
var auth = Authentication.FromPublishableKey("pk_live_...");

async Task<string?> CurrentUserAsync(string accessToken)
{
    try
    {
        var claims = await auth.VerifyAccessTokenAsync(accessToken, audience: "your-application-id");
        return claims.Subject;
    }
    catch (TokenVerificationException error)
    {
        Console.WriteLine($"rejected: {error.Reason}");
        return null;
    }
}

Errors

using System;
using Didit;

using var client = new DiditClient();

try
{
    await client.Sessions.RetrieveDecisionAsync("11111111-2222-3333-4444-555555555555");
}
catch (NotFoundException)
{
    Console.WriteLine("no such session");
}
catch (ApiStatusException error)
{
    Console.WriteLine($"{error.StatusCode} {error.RequestId}");
}

Lists and files

using System;
using Didit;

using var client = new DiditClient();

// Lists page through every result.
await foreach (var session in await client.Sessions.ListAsync(new SessionsListParams { Status = "Approved" }))
{
    Console.WriteLine(session.SessionId);
}

// Uploads take FileUpload.FromPath, FromBytes or FromStream.
var result = await client.IdVerification.VerifyAsync(new IdVerificationVerifyParams
{
    FrontImage = FileUpload.FromPath("id-front.jpg"),
    BackImage = FileUpload.FromPath("id-back.jpg"),
});
Console.WriteLine(result.IdVerification?.Status);

Server endpoint pages of the API reference have a .NET sample for their operation, except for the endpoints and fields that no 1.0.1 release has yet, named in the overview.

Guides

Authentication

Model Context Protocol (MCP)

Web SDKs

Native SDKs

Server SDKs

Integrations

C# and .NET SDK for KYC, AML and Transactions

Install

Configure the client

Create a session

Read the decision

Verify a webhook

Screen a transaction

Verify Authentication tokens

Errors

Lists and files

​Install

​Configure the client

​Create a session

​Read the decision

​Verify a webhook

​Screen a transaction

​Verify Authentication tokens

​Errors

​Lists and files

Install

Configure the client

Create a session

Read the decision

Verify a webhook

Screen a transaction

Verify Authentication tokens

Errors

Lists and files