Integrating PayPal payments into a Unity project involves several steps, and can be a little complicated for those unfamiliar with REST APIs. I chose to write this tutorial because back when I decided to monetize one of my games(add a small micro-transaction of 5$ in exchange for a life-time booster code) I looked up tutorials and scripts to integrate paypal with unity, but couldn’t find any that didn’t use a paid sdk from the unity store. Since there are few if any free alternatives to making your own implementation, here is what managed to figure out by reading documentations and using chatgpt a little.
I hope this helps you in future projects!
Step 1: Set Up a PayPal Developer Account
- Go to the PayPal Developer website and create a developer account if you don’t have one already.
- Log in to your PayPal Developer account and create a new application to obtain API credentials.
Step 2: Obtain API Credentials
- In the PayPal Developer Dashboard, navigate to the “Apps & Credentials” section.
- Create a new app and select the appropriate environment (sandbox for testing, live for production).
- Obtain the Client ID and Secret key for your app. These credentials will be used to authenticate your Unity app with PayPal.
Step 3: Unity Implementation
- Create a C# script:
Open your Unity project and create a new C# script (e.g.,PayPalManager.cs). - Implement PayPal Integration:
Use Unity’sUnityWebRequestto interact with PayPal’s REST API. Below is a simplified example:
using UnityEngine;
using UnityEngine.Networking;
using System.Collections;
public class PayPalManager : MonoBehaviour
{
private string clientId = "YOUR_CLIENT_ID";
private string secretKey = "YOUR_SECRET_KEY";
private string apiUrl = "https://api.paypal.com/v1/payments/payment";
void Start()
{
StartCoroutine(MakePaymentRequest());
}
IEnumerator MakePaymentRequest()
{
string accessToken = yield return GetAccessToken();
if (!string.IsNullOrEmpty(accessToken))
{
// Implement logic to create a payment request
string paymentRequestBody = "YOUR_PAYMENT_REQUEST_JSON_HERE";
UnityWebRequest request = UnityWebRequest.Post(apiUrl, paymentRequestBody);
request.SetRequestHeader("Authorization", "Bearer " + accessToken);
request.SetRequestHeader("Content-Type", "application/json");
yield return request.SendWebRequest();
if (request.isNetworkError || request.isHttpError)
{
Debug.LogError(request.error);
}
else
{
// Parse the payment response to get the approval URL
PaymentResponse paymentResponse = JsonUtility.FromJson<PaymentResponse>(paymentRequest.downloadHandler.text);
string approvalUrl = paymentResponse.links.Find(link => link.rel == "approval_url")?.href;
if (!string.IsNullOrEmpty(approvalUrl))
{
// Redirect the user to the PayPal approval URL
Application.OpenURL(approvalUrl);
}
else
{
Debug.LogError("Failed to obtain PayPal approval URL");
}
}
}
else
{
Debug.LogError("Failed to obtain access token");
}
}
IEnumerator GetAccessToken()
{
string authString = clientId + ":" + secretKey;
string base64Auth = System.Convert.ToBase64String(System.Text.Encoding.GetEncoding("ISO-8859-1").GetBytes(authString));
UnityWebRequest request = UnityWebRequest.Post(tokenEndpoint, "grant_type=client_credentials");
request.SetRequestHeader("Authorization", "Basic " + base64Auth);
request.SetRequestHeader("Accept", "application/json");
request.SetRequestHeader("Content-Type", "application/x-www-form-urlencoded");
yield return request.SendWebRequest();
if (request.isNetworkError || request.isHttpError)
{
Debug.LogError("Error obtaining access token: " + request.error);
yield return null;
}
else
{
// Parse and return the access token from the response
AccessTokenResponse response = JsonUtility.FromJson<AccessTokenResponse>(request.downloadHandler.text);
yield return response.access_token;
}
}
[System.Serializable]
private class AccessTokenResponse
{
public string access_token;
// Add additional fields if present in the actual response
}
}- Replace Placeholder Values:
ReplaceYOUR_CLIENT_ID,YOUR_SECRET_KEY,YOUR_PAYMENT_REQUEST_JSON_HERE
Here is an example of a payment request json:
{
"intent": "sale",
"payer": {
"payment_method": "paypal"
},
"transactions": [
{
"amount": {
"total": "10.00",
"currency": "USD"
},
"description": "Your payment description"
}
],
"redirect_urls": {
"return_url": "https://yourwebsite.com/success",
"cancel_url": "https://yourwebsite.com/cancel"
}
}You may read more about paypal’s REST API here.
The way this works is: Using your client ID and Secret, we make an REST call to paypal to get an access token. Using it, we ask paypal to generate a URL and then open it in the user’s default browser in order to process the payment. After the payment, based on the url given in the request json, the user will be redirected to either the “return_url” in case of success, or “cancel_url” in the case of failure.
Step 4: Test in the PayPal Sandbox
Before going live, test your implementation with PayPal sandbox credentials. PayPal provides sandbox credentials for testing, and it should work by basically replacing the actual production API credentials by the sandbox ones.
With it, you’ll be able to make a “fake request” and check if the whole system works. Keep an eye on the “Event Logs” tab while you try it out, there you’ll see any errors and/or what is going on behind the scenes.
