Mono.Core

A .NET client library for the Mono API — Connect, DirectPay, Disburse, Lookup (BVN / NIN / CAC / TIN / watchlist), Prove KYC, and a webhook controller with signature verification.

Targets netstandard2.0 — works on .NET Framework 4.6.1+, .NET Core 2.0+, .NET 5+, and Mono/Xamarin.

Install

dotnet add package Mono.Core

Configure

using Mono.Core;

services.AddMono(options =>
{
    options.BaseUrl = "https://api.withmono.com/v2";
    options.SecretKey = "your_secret_key";       // from app.mono.co/apps
    options.WebhookSecret = "your_webhook_secret"; // recommended
});

Need product-scoped keys (DirectPay + Disburse + Prove are separate apps on Mono's dashboard)? See docs/configuration.md.

Use

Inject any interface, every method returns MonoStandardResponse<T>:

public class OnboardingService
{
    private readonly IMonoCustomers _customers;

    public OnboardingService(IMonoCustomers customers) => _customers = customers;

    public async Task<string> CreateAsync(string bvn)
    {
        var response = await _customers.CreateIndividualCustomer(new CreateIndividualCustomerModel
        {
            FirstName = "Ada",
            LastName = "Lovelace",
            Email = "ada@example.com",
            Phone = "+2348012345678",
            Identity = new CustomerIdentity { Type = "bvn", Number = bvn },
        });

        if (!response.Success) throw new InvalidOperationException(response.Message);
        return response.Data.Id;
    }
}

Documentation

Guide	What it covers
Getting started	10-minute walkthrough — install → call → webhook
Configuration	Per-product keys, base URLs, webhook secret, DI registration
Error handling	MonoStandardResponse<T>, when things fail, what to log
Webhooks	Signature verification, full event reference, idempotency
Connect	IMonoAccounts + IMonoCustomers (account linking, balance, statements, transactions)
DirectPay	One-time payments, mandates, refunds, payouts, sub-accounts
Disburse	Outbound payouts to one or many recipients
Lookup	BVN, NIN, CAC, TIN, drivers-license, mashup, credit history
Watchlist	Sanctions / PEP / adverse-media screening + monitoring
Prove	Full-stack KYC verification (tier 1/2/3)
Migration guide	Upgrading from an earlier version
Changelog	Per-release notes

Interfaces at a glance

Service	Purpose	Mono product
IMonoAccounts	Account linking, balance, statements, transactions	Connect
IMonoCustomers	Customer modeling, list/CRUD, linked-account enumeration	Connect
IMonoAuthorization	Authorize / reauthorize / sync linked accounts	Connect
IMonoDirectPay	One-time payments, mandates, refunds, payouts, sub-accounts	DirectPay
IMonoDisburse	Outbound payouts (source accounts → batches → distributions)	Disburse
IMonoLookUp	BVN, NIN, CAC, TIN, drivers-license, address, mashup, credit history	Lookup
IMonoWatchlist	Sanctions / PEP screening, ongoing monitoring	Lookup
IMonoProve	Full-stack KYC verification	Prove
IMonoMiscellaneous	Coverage, unlink account	misc

Contributing

Issues + PRs welcome. For substantial changes, open an issue first so we can align on the approach. Keep PRs focused — one product surface or one bug per PR makes review tractable.

Run the test suite locally:

dotnet test

The suite has four layers — unit, JSON contract, Refit HTTP wire, and optional sandbox integration. The sandbox layer is gated behind environment variables and skips automatically when they're not set:

export MONO_SANDBOX_KEY="test_sk_..."
export MONO_SANDBOX_LOOKUP_KEY="test_sk_..."  # optional, for Lookup endpoints
export MONO_SANDBOX_ACCOUNT_ID="..."           # optional, for account-data tests
dotnet test

License

MIT