.NET / C#

The Sanwo NuGet package provides ASP.NET Tag Helpers that render Sanwo checkout buttons and custom amount forms. Configure via dependency injection, use in any Razor view.

Installation

dotnet add package Sanwo

Configuration

Register Sanwo in Program.cs:

Inline

builder.Services.AddSanwo(options =>
{
    options.Provider = "paystack";
    options.PublicKey = "pk_test_xxxxx";
    options.Currency = "NGN";
});

appsettings.json

{
  "Sanwo": {
    "Provider": "paystack",
    "PublicKey": "pk_test_xxxxx",
    "Currency": "NGN",
    "Debug": false
  }
}

builder.Services.AddSanwo(builder.Configuration.GetSection("Sanwo"));

Register Tag Helpers

In _ViewImports.cshtml:

@addTagHelper *, Sanwo

Add the script

In your layout (_Layout.cshtml), before </body>:

<sanwo-scripts />

Checkout button

<sanwo-checkout
    amount="500000"
    email="customer@example.com"
    button-text="Pay ₦5,000" />

Available attributes

Attribute	Type	Required	Default	Description
amount	int	Yes	—	Amount in minor units (kobo, cents)
email	string	Yes	—	Customer email
button-text	string	No	“Pay Now”	Button label
button-class	string	No	“sanwo-button”	CSS class
provider	string	No	Config value	Provider name
public-key	string	No	Config value	Public key
currency	string	No	Config value	Currency code
description	string	No	—	Payment description
reference	string	No	Auto-generated	Transaction reference
first-name	string	No	—	Customer first name
last-name	string	No	—	Customer last name
phone	string	No	—	Customer phone
callback	string	No	—	JS callback function name
template-url	string	No	—	Custom provider template URL

Examples

Basic:

<sanwo-checkout amount="500000" email="user@example.com" />

With model data:

<sanwo-checkout
    amount="@Model.TotalInKobo"
    email="@User.Identity.Name"
    first-name="@Model.FirstName"
    button-text="Complete Purchase"
    description="Order #@Model.OrderId" />

Override provider:

<sanwo-checkout
    amount="500000"
    email="user@example.com"
    provider="flutterwave"
    public-key="FLWPUBK_TEST-xxxxx" />

Custom amount form

Let customers enter their own amount:

<sanwo-custom-amount
    email="donor@example.com"
    button-text="Donate"
    placeholder="How much would you like to give?"
    min-amount="500"
    max-amount="1000000" />

Custom amount attributes

Attribute	Type	Required	Default	Description
button-text	string	No	“Pay Now”	Button label
placeholder	string	No	“Enter amount”	Input placeholder
email	string	No	—	If omitted, email input is shown
min-amount	int	No	—	Minimum amount (major units)
max-amount	int	No	—	Maximum amount (major units)
provider	string	No	Config value	Provider name
currency	string	No	Config value	Currency code
callback	string	No	—	JS callback function name

Handling results

JavaScript callback:

<script>
    function onPaid(result) {
        if (result.status === 'successful') {
            fetch('/api/payments/verify', {
                method: 'POST',
                headers: { 'Content-Type': 'application/json' },
                body: JSON.stringify({ reference: result.reference })
            });
        }
    }
</script>

<sanwo-checkout
    amount="500000"
    email="user@example.com"
    callback="onPaid" />

DOM events:

<script>
    document.addEventListener('sanwo:complete', function(e) {
        if (e.detail.status === 'successful') {
            window.location.href = '/thank-you?ref=' + e.detail.reference;
        }
    });
</script>

Custom provider templates

Use any payment gateway — not just the built-in five — by providing your own provider template. See the custom providers guide for how to write templates.

Via template URL

Host your template HTML file and pass its URL:

<sanwo-checkout
    amount="500000"
    email="customer@example.com"
    provider="custom"
    public-key="pk_test_xxxxx"
    template-url="https://example.com/my-provider-template.html"
    button-text="Pay with My Gateway" />

Programmatic approach

For full control over provider options, use Sanwo.create() with a custom template:

<sanwo-scripts />

<button id="custom-pay">Pay with My Gateway</button>

<script>
    var sanwo = Sanwo.create({
        provider: 'custom',
        publicKey: 'pk_test_xxxxx',
        templateUrl: 'https://example.com/my-provider-template.html',
        providerId: 'my-gateway',
    });

    document.getElementById('custom-pay').addEventListener('click', async function() {
        var result = await sanwo.checkout({
            amount: 500000,
            currency: 'NGN',
            customer: { email: 'customer@example.com' },
        });

        if (result.status === 'successful') {
            window.location.href = '/thank-you?ref=' + result.reference;
        }
    });
</script>

Source code

Sanwohq/dotnet on GitHub.