Legichain 0.2.0

Legichain .NET SDK

Official .NET client for the Legichain AML, KYC and Travel Rule API.

dotnet add package Legichain --version 0.1.0

• .NET 8 + .NET Standard 2.0 (works on .NET Framework 4.6.1+)
• System.Net.Http.HttpClient + System.Text.Json — no third-party deps on net8
• Typed LegichainException carries the full RFC 7807 problem body
• HMAC-SHA256 webhook verifier (constant-time compare)

Get an API key

Sign up at https://legichain.com — the Free plan ships with 1 RPS and 300 monthly credits, no card required. Once signed in:

panel.legichain.com → Settings → API Keys → New key

Keys look like lc_live_<22>.sk_live_<44> (production) or lc_test_<22>.sk_test_<44> (test mode — never spends credits, safe in CI). Store the secret half in your secret manager — the Argon2 hash means a lost key can't be recovered. See the full API guide for plans, rate limits and reference docs.

Quick start

using Legichain;
using Legichain.Models;

using var lc = new LegichainClient(Environment.GetEnvironmentVariable("LEGICHAIN_API_KEY")!);

try
{
    var r = await lc.ScreenPersonAsync(
        new PersonQuery("Vladimir Putin", Country: "RU", BirthDate: "1952-10-07"));

    switch (r.Summary.Recommendation)
    {
        case Recommendation.Block:  DenyOnboarding(customerId);                       break;
        case Recommendation.Review: QueueForCompliance(customerId, r.ScreeningId);    break;
        case Recommendation.Clear:  ApproveOnboarding(customerId);                    break;
    }

    Console.WriteLine($"{r.CostCredits} credits spent; {r.CreditsRemaining} remaining");
}
catch (LegichainException e)
{
    // RFC 7807 — branch on stable codes
    switch (e.Code)
    {
        case "BIL_001_INSUFFICIENT_CREDITS": TopUp();           break;
        case "RL_001_RATE_LIMITED":          await Backoff();   break;
        case "AUTH_002_INVALID_TOKEN":       RotateKey();       break;
        default:                             Log(e.Status, e.Detail); break;
    }
}

Company + crypto wallet

var company = await lc.ScreenCompanyAsync(
    new CompanyQuery("Rosneft Oil Company", Country: "RU"));

var wallet = await lc.ScreenCryptoAsync(
    new CryptoQuery("0x098B716B8Aaf21512996dC57EB0615e2383E2f96"));

Batch (sync + async)

var items = new object[]
{
    new PersonQuery("Acme Trading GmbH"),
    new CryptoQuery("TVj7RNVH...", "tron"),
    new PersonQuery("Maria Lopez", "ES"),
};

// up to 200 items synchronously
var results = await lc.ScreenBatchAsync(items);

// async — result delivered to your webhook
var job  = await lc.ScreenBatchAsyncJobAsync(items, webhookUrl: "https://you.example.com/webhooks/legichain");
var done = await lc.GetJobAsync(job.JobId);

PDF reports

byte[] pdf = await lc.ReportWalletAsync(new CryptoQuery(
    "0x6c0bD2BB04Fda9CBfeBb8DC1208Db32a0F8a4Edd", "eth"));
await File.WriteAllBytesAsync("wallet.pdf", pdf);

Idempotency

await lc.ScreenPersonAsync(
    new PersonQuery("Maria Lopez"),
    idempotencyKey: "onboarding-2026-05-20-7f3c");
// Re-running the same key within 24h returns the cached response.

Webhook verification (ASP.NET Core)

using Legichain;

app.MapPost("/webhooks/legichain", async (HttpContext ctx) =>
{
    using var ms = new MemoryStream();
    await ctx.Request.Body.CopyToAsync(ms);
    var body = ms.ToArray();

    var ok = Webhooks.VerifySignature(
        body,
        ctx.Request.Headers["Legichain-Signature"]!,
        Environment.GetEnvironmentVariable("LEGICHAIN_WEBHOOK_SECRET")!);

    if (!ok) return Results.Unauthorized();
    // ... handle the event
    return Results.Ok();
});

Configuration

using var lc = new LegichainClient(
    apiKey: key,
    baseUrl: "https://staging.api.legichain.com",
    requestTimeout: TimeSpan.FromSeconds(60),
    defaultHeaders: new Dictionary<string, string> { ["X-My-App"] = "billing-svc" });

Inject your own HttpClient (e.g. one that goes through a corporate proxy or uses IHttpClientFactory):

var handler = new HttpClientHandler
{
    Proxy    = new WebProxy("http://proxy.bank.tr:8080"),
    UseProxy = true,
};
var http = new HttpClient(handler);

using var lc = new LegichainClient(key, httpClient: http);

Reference

Versioning & support

• Tracks API v1. Breaking changes ship on /v2/ with ≥ 6 months overlap.
• Status: https://legichain.com/status
• Email: contact@legichain.com
• GitHub: https://github.com/legichain/legichain-dotnet