Before you add the SDK to your iOS app you will need to create a client token that can be used to authenticate the transaction.

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Install a server-side SDK

Use the package manager in your preferred programming language to install our server-side SDK. Token generation can only be done server side and we do not recommend doing this client side as it will expose your API key to your customers.

dotnet add package Gr4vy

Please always check and install the latest release of your preferred SDK.

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Initialize the SDK client

Next, initialize the SDK with the ID of your instance and the private key.

using Gr4vy;
using Gr4vy.Models.Components;
using System.Collections.Generic;

// Loaded the key from a file, env variable, 
// or anywhere else
var privateKey = "..."; 

var sdk = new Gr4vySDK(
    id: "example",
    server: SDKConfig.Server.Sandbox,
    bearerAuthSource: Auth.WithToken(privateKey),
    merchantAccountId: "default"
);

The Gr4vy ID is the unique identifier for your instance. Together with the environment (sandbox or production) it is used to connect to the right APIs.

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Generate a token

The next step is to create a new token for frontend authentication. The SDK comes with a helper function for exactly that purpose. It requires an amount and currency for the transaction to be created and additionally accepts either the ID of a buyer or your external identifier for a buyer to link the transaction to.

using Gr4vy;

// Loaded the key from a file, env variable, 
// or anywhere else
var privateKey = "..."; 

var sdk = new Gr4vySDK(
    id: "example",
    server: SDKConfig.Server.Sandbox,
    bearerAuthSource: Auth.WithToken(privateKey),
    merchantAccountId: "default"
);

var checkoutSession = await sdk.CheckoutSessions.CreateAsync()

auth.get_embed_token(
    privatekey,
    embedParams=new Dictionary<string, object>
    {
        ["amount"]: 1299,
        ["currency"]: 'USD',
        ["buyer_external_identifier"]: 'user-1234',
    },
    checkoutSessionId=checkoutSession.ID
)

This token can now be served to the frontend where it will be used by our SDK.

If you would prefer to generate the client token without using a server-side SDK, then please read our guide on manually generating a JWT.

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Checkout sessions

We recommend passing a checkout session ID to the Embed token function. This ID can be used to help identify multiple transaction attempts. This is useful to identify if one or more failed/declined transactions eventually result in a successful transaction. Checkout sessions can store also store cart_items, metadata, airline data, and more, removing the need to pass these values on the transaction request.

using Gr4vy;
using Gr4vy.Models.Components;
using NodaTime;
using System;
using System.Collections.Generic;

// Init SDK

var res = await sdk.CheckoutSessions.CreateAsync(checkoutSessionCreate: new CheckoutSessionCreate() {
    CartItems = new List<CartItem>() {
        new CartItem() {
            Name = "GoPro HD",
            Quantity = 2,
            UnitAmount = 1299,
            DiscountAmount = 0,
            TaxAmount = 0,
            ExternalIdentifier = "goprohd",
            Sku = "GPHD1078",
            ProductUrl = "https://example.com/catalog/go-pro-hd",
            ImageUrl = "https://example.com/images/go-pro-hd.jpg",
            Categories = new List<string>() {
                "camera",
                "travel",
                "gear",
            },
            ProductType = "physical",
            SellerCountry = "GB",
        },
        new CartItem() {
            Name = "GoPro HD",
            Quantity = 2,
            UnitAmount = 1299,
            DiscountAmount = 0,
            TaxAmount = 0,
            ExternalIdentifier = "goprohd",
            Sku = "GPHD1078",
            ProductUrl = "https://example.com/catalog/go-pro-hd",
            ImageUrl = "https://example.com/images/go-pro-hd.jpg",
            Categories = new List<string>() {
                "camera",
                "travel",
                "gear",
            },
            ProductType = "physical",
            SellerCountry = "GB",
        },
        new CartItem() {
            Name = "GoPro HD",
            Quantity = 2,
            UnitAmount = 1299,
            DiscountAmount = 0,
            TaxAmount = 0,
            ExternalIdentifier = "goprohd",
            Sku = "GPHD1078",
            ProductUrl = "https://example.com/catalog/go-pro-hd",
            ImageUrl = "https://example.com/images/go-pro-hd.jpg",
            Categories = new List<string>() {
                "camera",
                "travel",
                "gear",
            },
            ProductType = "physical",
            SellerCountry = "US",
        },
    },
    Metadata = new Dictionary<string, string>() {
        { "cohort", "cohort-a" },
        { "order_id", "order-12345" },
    },
    Buyer = new GuestBuyerInput() {
        DisplayName = "John Doe",
        ExternalIdentifier = "buyer-12345",
        BillingDetails = new BillingDetailsInput() {
            FirstName = "John",
            LastName = "Doe",
            EmailAddress = "john@example.com",
            PhoneNumber = "+1234567890",
            Address = new Address() {
                City = "San Jose",
                Country = "US",
                PostalCode = "94560",
                State = "California",
                StateCode = "US-CA",
                HouseNumberOrName = "10",
                Line1 = "Stafford Appartments",
                Line2 = "29th Street",
                Organization = "Gr4vy",
            },
            TaxId = new TaxId() {
                Value = "12345678931",
                Kind = "ar.cuit",
            },
        },
        ShippingDetails = new ShippingDetailsCreate() {
            FirstName = "John",
            LastName = "Doe",
            EmailAddress = "john@example.com",
            PhoneNumber = "+1234567890",
            Address = new Address() {
                City = "San Jose",
                Country = "US",
                PostalCode = "94560",
                State = "California",
                StateCode = "US-CA",
                HouseNumberOrName = "10",
                Line1 = "Stafford Appartments",
                Line2 = "29th Street",
                Organization = "Gr4vy",
            },
        },
    },
});

// handle response

Checkout session expiry

Checkout sessions expire after 1 hour by default. Updating a checkout session will not extend the time.

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Loading token in iOS

The token needs to be shared with your iOS application via your own API. We recommend you create a token per checkout and only use a token for a short amount of time.

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Summary

In this step you:

  • Created a signed JWT token using a server-side SDK.
  • Shared the JWT with your iOS application