Engineering Services
WooCommerce Payment Gateway Integrations Built for the Payments That Fail.
We build and integrate payment gateways for WooCommerce: a gateway plugin for a provider that has none, extra logic on top of an existing one, or several gateways working together at checkout. The focus is what happens when a payment is declined, delayed or reported twice, because that is where most gateway problems start.
The Problems We Solve
Engineering Solutions for Complex Payment Gateway Integrations Challenges.
A gateway demo shows one successful card payment. Real stores also get declines, timeouts, customers who close the tab, and confirmations that arrive late or twice. The problems below are what we plan for in every gateway integration.
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Orders in the wrong status
After a decline or a timeout the order can sit in a status that does not match what happened, so stock, emails and reports disagree with the payment.
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Paid orders stuck on pending
The payment succeeds at the provider but the order never moves on, usually because the confirmation webhook did not arrive or was rejected.
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Duplicate or missing webhooks
Providers send the same event twice, out of order, or not at all. An endpoint that assumes otherwise will double-process or miss payments.
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Payment fields that do not load
Card fields or wallet buttons that disappear at checkout because of a script conflict, a theme change or a missing setting.
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Refunds that do not sync
Full and partial refunds made in WooCommerce or in the provider dashboard that never show up on the other side.
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Several gateways, one checkout
Rules for which gateway appears where, by country, currency, cart or customer, that become tangled as more are added.
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Provider API changes
Expiring credentials, retired endpoints and changed response formats that break a gateway that worked for years.
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Test mode mixed with live
A gateway left in test mode on a live store, or live and test keys mixed up, so real orders are not really paid.
What We Do
Our Payment Gateway Integrations Services.
Gateway work ranges from fixing one webhook to building a gateway plugin from scratch. The services below cover the shapes it usually takes.
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Custom Gateway Plugin Development
A WooCommerce payment gateway plugin built against the provider's API and WooCommerce's payment gateway and order-status architecture.
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Existing Provider Integrations
Connecting a provider's API or SDK to WooCommerce where the official plugin does not fit, or does not exist.
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Hosted Fields and Redirect Flows
Where the provider offers them, we use hosted fields or redirect pages so card details go to the provider, not through your site.
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Webhook Receivers
Endpoints built for duplicate, late and out-of-order events, with verified signatures and a log of what arrived.
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Refunds, Captures and Voids
Refund and capture flows that stay in step between WooCommerce and the provider.
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Multi-Gateway Checkout Logic
Rules that decide which gateways a customer sees, by country, currency, cart contents or customer, kept readable and testable.
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Multisite and Multi-Currency Setups
Gateways for WordPress Multisite networks and for stores selling in more than one currency.
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Gateway Audits and Troubleshooting
A review of an existing gateway setup: statuses, webhooks, logs and settings, with written findings.
Featured Case Studies
Real Payment Gateway Integrations Engagements.
Payment engineering from our Case Studies: a unified multi-gateway checkout engine, and a payment gateway built for WordPress Multisite.
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40% E-Commerce / Retail
Bespoke Checkout & Payment Gateway Engineering
A unified WooCommerce checkout and multi-gateway payment engine, written in custom code without third-party gateway plugins — reduced checkout latency by 40%.
Result: 40% reduction in checkout page latency (figure from the project's internal documentation)
Read Case Study -
Network-Wide Agencies / Multisite Networks
Multisite-Compatible Network Payment Gateway
A payment gateway engineered for WordPress Multisite (WPMU), centralising billing across the whole network, with no fixed limit on the number of sub-sites, instead of configuring payments per site.
Read Case Study
Our Engineering Process
How We Deliver.
Most gateway faults are found at the boundary nobody tested: the declined card, the late confirmation, the repeated webhook. Our process surfaces those cases before launch.
Discovery
Which provider, which payment methods, which countries and currencies, and what the order should do at every stage.
Design
The order-status map, the webhook events to handle and the failure cases, written down before any code.
Build
The gateway built to that design, following WooCommerce's own payment and order APIs.
Sandbox Testing
Declines, timeouts, repeated and out-of-order webhooks and refunds tested in the provider's sandbox.
Go-live
A supported launch with the live credentials checked, a real low-value payment and the checkout tested end to end.
Support
Ongoing help as the provider and WooCommerce change, and watching for failures once the gateway is live.
Technologies We Use
The Stack Behind the Work.
Gateway engineering is API and order-flow work. These are the standards and tools involved.
Payments
Protocols
Platform
Background Work
Infrastructure
Related Engineering Articles
From the Engineering Journal.
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KODENZO Commerce Health
Is your store as fast and healthy as you think?
Find out in a few minutes, free. Then let PRO watch checkout for you in the background.
- Read-only checks across configuration, cache, database and updates
- A health score with plain-language next steps
- Nothing changes on your site, and no data is sent to us
Free on WordPress.org. Nothing in the free plugin is locked.
- Measures real-visitor checkout speed (LCP, INP and CLS) in the background
- Watches payments, checkout errors and plugin changes
- Emails you when something needs attention
PRO tells you what it finds. It does not fix problems for you.
Why KODENZO
Engineering Partner, Not Just a Developer.
A payment integration is judged by what it does when something goes wrong. This is what that standard changes about how we build.
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Failure First
We design the declined, delayed and duplicated cases before the happy path.
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Order-Status Discipline
Every payment outcome maps to a clear WooCommerce order status.
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Reliable Webhooks
Receivers that cope with repeats, delays and bad signatures.
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Card Data Stays With the Provider
Hosted fields or redirects wherever the provider supports them.
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Tested Before Live
Sandbox testing of failures, not only successful payments.
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Written Handover
What was built, how it is configured and how to check it.
FAQ
Questions, Answered.
Questions we hear before a payment gateway project starts.
Yes. We build against the provider's API and WooCommerce's payment gateway and order-status architecture. Whether it is practical depends on the provider's API, which we check first.
We design around the provider's hosted fields or redirect pages wherever the provider offers them, so card details go to the provider. We do not make compliance claims for your store: that depends on how you integrate and on your provider's requirements.
Usually the confirmation never reached the store: the webhook did not arrive, was rejected, or points at the wrong address. We check the provider's event log, your store's logs and the webhook settings.
Yes. We look at the logs and a staging copy first, then either fix it or tell you plainly that replacing it would be cheaper.
We build gateways to work with both the classic and the block checkout, and say up front if a provider's SDK limits that.
Your provider's dashboard shows its side. Commerce Health PRO tracks failure rate and confirmation time for each gateway from your real orders and emails you when they slip. It reports problems; it does not fix them.
It depends on the provider and the scope. After reading your brief we give a written estimate. A free store audit is a good way to start if you are not sure what is wrong.
No questions match your search.
Need Experienced Payment Gateway Integrations Engineers?
Whether you're building a new commerce platform, optimising an existing store, or solving a complex engineering challenge, KODENZO can help.