Great question—this is a super common pain point with payment gateways, especially when dealing with user-initiated interruptions or network blips. Let’s break down the reliable fixes you can implement in your .NET MVC app with RazorPay to ensure you never miss a payment record:

The biggest flaw in relying solely on the user’s post-payment redirect is that the user can break that flow intentionally or accidentally. Instead, leverage RazorPay’s server-side webhook notifications—these are direct, automated requests RazorPay sends to your backend as soon as a payment’s status changes, regardless of what the user does.

Here’s how to set this up:

• In your RazorPay dashboard, configure a webhook URL pointing to a dedicated action in your MVC controller (e.g., https://yourapp.com/api/razorpay/webhook).
• In that controller action, first validate the RazorPay signature using the webhook secret from your dashboard—this prevents fake requests from malicious actors. You can use RazorPay’s .NET SDK to handle this easily with Utils.ValidateWebhookSignature().
• Once the signature is verified, check the payment status from the webhook payload. If it’s captured (success), update your database with the payment details.
• Add idempotency: Use the payment_id from the payload as a unique key in your database. Before inserting, check if a record with that payment_id already exists—this handles cases where RazorPay retries the webhook (which it will do if your server doesn’t return a 200 OK).

Webhooks are reliable, but they can fail if your server is down or there’s a network outage. To cover this gap, implement a scheduled polling job to check the status of pending payments in your database.

For .NET MVC, tools like Hangfire or Quartz.NET work perfectly for this:

• Mark orders as Pending when you first initiate the payment request.
• Create a recurring job that runs every 1–5 minutes (adjust based on your needs) to fetch all Pending orders.
• For each order, call RazorPay’s Fetch Payment Details API using the payment_id stored in your database.
• If the API returns a captured status, update the order to Paid and save the payment details. If it’s failed, mark it as such. After a set number of retries (e.g., 10 times over an hour), mark the order as Awaiting Review for manual follow-up.

Even with webhooks and polling, it’s helpful to give users a way to confirm their payment status if they notice the redirect failed. Here’s how:

• When RazorPay redirects users back to your return URL, load a page that automatically makes an AJAX request to your backend to verify the payment status.
• If the request fails (network error, or backend still sees it as pending), display a clear button like "Confirm My Payment" that triggers the same verification request again.
• Add a simple loading state and success/error messages to keep the user informed. This covers cases where the user clicked back or the redirect timed out.

When you send the initial payment request to RazorPay, include a custom idempotency_key (a unique string generated by your app, like a GUID tied to the order). This ensures that even if the user accidentally triggers multiple payment requests, RazorPay won’t charge them more than once.

In your backend, store this key alongside the order, so when processing webhooks or polling, you can tie the payment back to the correct order without duplication.

Key Notes to Avoid Headaches #

• Always validate signatures: Never trust webhook or API payloads without verifying the signature—this is non-negotiable for security.
• Log everything: Keep detailed logs of webhook requests, polling attempts, and payment status changes. This makes debugging a breeze when things go wrong.
• Alert on anomalies: Set up email/Slack alerts for orders that stay Pending longer than a threshold (e.g., 2 hours) so your team can follow up manually.

Putting it all together: Webhooks should be your primary mechanism, polling as a safety net, and client-side prompts to handle user-initiated interruptions. This combo ensures you don’t lose any payment records, no matter what happens during the user’s flow.

内容的提问来源于stack exchange，提问作者Oxygen