Your payment processing just broke. Customers want to buy, but your checkout is throwing errors, webhooks are failing, and fulfillment has stalled. Every hour your payment gateway is down is unrecoverable revenue walking away. We run immediate diagnostics and get your cash register running before the day ends.
Payment gateway failures after a site update almost always come down to one of three things: an authentication token that broke, a payload structure that changed, or a webhook endpoint that stopped receiving events. We find which one — and fix it — fast.
You describe the symptom — the error message customers see, which checkout flow breaks, when it started, what changed on the site before it broke. We attempt to reproduce the failure in your environment and capture the exact API error response. Stripe and PayPal return specific error codes that tell us exactly which layer of the integration failed: card_error, api_error, authentication_error, invalid_request_error — each one points to a different part of the integration.
Most checkout failures are diagnosed in under 20 minutes. The error code and the recent change history almost always point to the same place.
We inspect the full integration layer: API key validity and scope, authorization header format, API version in use versus version expected, payload structure against the current API schema, webhook endpoint URL and signing secret, event handler registration, and idempotency key implementation. We also check your Stripe or PayPal dashboard logs directly — the gateway's own event log shows every request it received and what it returned, which tells us definitively whether the problem is on your side or theirs.
Gateway logs don't lie. If Stripe received a malformed payload, the log shows the exact field that failed validation. If your webhook endpoint stopped responding, the delivery attempts show the HTTP response it got — or didn't get.
We apply the specific fix: rotating and correctly scoping the API key, fixing the malformed payload field, updating the API version reference, correcting the webhook endpoint URL or signing secret, rebuilding the event handler for the correct event type. Then we run test transactions through the complete checkout flow — charge creation, payment intent confirmation, webhook delivery to your fulfillment system, and receipt confirmation — using Stripe's test mode or PayPal's sandbox before touching live transactions.
We do not declare it fixed until a test transaction completes end-to-end — from checkout form submission to successful charge creation to webhook delivery to your fulfillment system.
With test transactions confirmed, we run a live transaction to verify the full flow works in production — charge creates, webhook fires, fulfillment receives the order data, customer receives confirmation. We monitor the first several live transactions to confirm everything is stable before signing off.
You receive a written account of what the failure was, what caused it, and what we changed — along with a recommendation for how to prevent the same class of failure after future site updates. Your checkout is running. Your customers can pay. The revenue channel is open again.
Checkout failures after site updates follow predictable patterns. These are the failures we diagnose and fix most often.
Expired, incorrectly scoped, or misconfigured API keys causing authentication failures at the gateway level.
Malformed charge requests, missing required fields, or API version mismatches causing invalid_request_error responses.
Broken webhook endpoints, incorrect signing secrets, or missing event handler registrations causing fulfillment to stall after successful charges.
Order data flowing correctly to your fulfillment system, inventory platform, or order management tool — confirmed via end-to-end test transactions.
Gateway event log review identifying any charges that succeeded during the outage but whose webhook data was lost — so no orders fall through the cracks.
Once checkout is stable, a recommended path to proper revenue instrumentation, billing logic, and financial reporting dashboards.
Stripe, PayPal, Braintree, Square, Authorize.Net, and Shopify Payments. We also debug payment integrations built through WooCommerce, Webflow, and custom implementations using any of these gateways' APIs. If you're using a gateway not on this list, tell us — the debugging approach is the same regardless of the platform.
In order of frequency: an API key that was regenerated or not carried over during the update, a JavaScript file version that broke the payment form initialization, a Content Security Policy header that now blocks the gateway's scripts, a webhook endpoint URL that changed, or a plugin/dependency update that introduced an API version mismatch. We check all of these in the first 20 minutes.
We review the gateway's event log to identify any charges that succeeded before or during the failure period whose corresponding webhook events were never delivered to your fulfillment system. We can replay those webhook events or manually extract the order data so no paid order falls through the cracks. This is part of the standard fix, not an add-on.
Both. We verify the complete flow in test mode first to confirm the fix without touching real money. Once test transactions pass end-to-end, we run a controlled live transaction to confirm the production environment behaves identically. We monitor the first several live transactions before signing off.
We check Stripe's status page immediately as part of the initial diagnosis. If the failure is on the gateway's end — a degraded API, a regional outage — we document that, give you the Stripe status link to monitor, and recommend any client-side mitigation (graceful error messaging, retry logic). We do not charge for engagements where the root cause is confirmed to be the gateway provider, not your integration.
Yes. We document a checkout-integrity checklist specific to your stack — the exact things to verify after any site update that touches payment-related code, API keys, or Content Security Policy headers. Clients who want automated monitoring that catches payment failures the moment they happen, rather than when a customer reports it, can discuss that as a next engagement.
The cart is down right now. Submit the problem and we will have your payment gateway running and your checkout confirmed with live transactions before you close your laptop tonight.