Technical diagnosis
Root-cause investigation of a specific problem, with a written technical report.
- Root-cause investigation
- Technical findings
- Recommended next steps and scope
Senior WooCommerce engineering
WooCommerce broken? Get a senior engineer on the problem.
Checkout failures, payment errors, broken orders, plugin conflicts, PHP errors, database problems and complex WooCommerce issues need more than another plugin or a quick workaround.
Urgent technical issues are assessed based on severity, availability and scope.
WooCommerce system status
Root cause found
- CHECKOUT
- custom-fees.php:142
- Error
- PAYMENT
- not reached
- OK
- ORDERS
- OK
- HPOS
- OK
- API
- unrelated
- Warning
00:00reproduce checkout · guest · card
00:03POST /?wc-ajax=checkout → 500
00:06check payment callback
00:07no gateway request · failure is before payment
00:11tail wp-content/debug.log
00:12PHP Fatal error: Uncaught TypeError: Unsupported operand types: string + float in custom-fees.php:142
00:14hook: woocommerce_cart_calculate_fees
Root cause found
A custom fee callback receives a string after the last plugin update. Checkout fails while calculating totals — before any payment request is sent.
next: fix → test on staging → document
Senior engineering
Direct technical communication. No account managers in between.
Root-cause first
We investigate before recommending fixes.
Production experience
Code, infrastructure, databases and integrations.
Documented
You know what was changed and why.
What we fix
What can go wrong?
Each area links to a technical guide: symptoms, likely causes, how the problem is diagnosed and when to involve an engineer.
Orders not completing
Endless spinner, Place Order failing, guest checkout broken after an update.
POST /?wc-ajax=checkout → 500/woocommerce/checkout/not-working/Gateway and callback failures
Customer charged but order failed, 3D Secure loops, webhooks not arriving.
payment: captured · order: pending/woocommerce/payments/customer-charged-order-failed/Missing or incorrect orders
Orders not created, wrong totals, statuses that never change.
sum(line_items) ≠ order_total/woocommerce/orders/missing/Fatal errors and white screens
Critical errors after plugin, theme or PHP version updates.
PHP Fatal error: Uncaught Error/woocommerce/errors/php-fatal-error/Broken front-end behaviour
Checkout scripts failing, blocked AJAX, cart fragments not refreshing.
ReferenceError: jQuery is not defined/woocommerce/errors/Conflicts and incompatibilities
Two extensions hooking the same flow, or an update that changed behaviour.
same hook · same priority · 2 plugins/woocommerce/errors/plugin-conflict/Slow checkout and admin
Slow queries, uncached requests, saturated PHP workers.
slow query · wp_postmeta · 3.2 s/woocommerce/performance/Order storage compatibility
Custom code still reading orders from wp_posts after the switch.
get_post_meta( $order_id ) → ''/woocommerce/hpos/custom-code/Broken integrations
REST API authentication errors, timeouts and malformed payloads.
401 woocommerce_rest_cannot_view/woocommerce/integrations/rest-api/Deliveries failing
Webhooks disabled after failed deliveries, payload or signature issues.
delivery → HTTP 500 · failed/woocommerce/integrations/webhooks/Infrastructure problems
PHP-FPM, Nginx, Cloudflare, memory limits and timeouts.
upstream timed out (110)/woocommerce/performance/Data and query problems
Locks, inconsistent data, Action Scheduler backlogs.
Deadlock found when trying to get lock/woocommerce/errors/How we investigate
We follow the failure through the whole stack.
A checkout spinner can be a PHP fatal error, a blocked script, a gateway timeout or a locked database row. We trace the request layer by layer until the failing one is isolated.
| # | Layer | Components | What we inspect | Result |
|---|---|---|---|---|
| L1Browser | checkout.js · AJAX | Network panel, console errors, request payloadPOST /?wc-ajax=checkout → 500 | Symptom | |
| L2Edge | Cloudflare · DNS · TLS | Cache rules, WAF events, redirects | Checked · clear | |
| L3Web server | Nginx · Apache | Access and error logs, upstream status | Checked · clear | |
| L4PHP runtime | PHP-FPM · OPcache | PHP error log, FPM slow log, limits | Checked · clear | |
| L5Application | WordPress · WooCommerce · plugins | Hooks, WooCommerce logs, recent changescustom-fees.php:142 · string + float | Fault isolated | |
| L6Data | MySQL · Redis · HPOS | Queries, locks, order data consistency | Checked · clear | |
| L7Background jobs | Action Scheduler · WP-Cron | Failed and past-due actions | Checked · clear | |
| L8External | Gateways · ERP · webhooks | Callbacks, signatures, API responses | Not reached |
Example trace. Same failure as the diagnostic session above: isolated in the application layer, before the payment gateway is reached.
Why senior engineering
Fix the problem.Not just the symptom.
A workaround makes the error disappear today. A root-cause fix explains why it happened, changes the right thing and keeps it from coming back after the next update.
| Quick workaround | Root-cause engineering |
|---|---|
| Deactivate the plugin that seems to cause the error. | Find the hook, the change and the condition that break the checkout request. |
Raise memory_limit until the fatal error goes away. | Profile what is consuming memory and why it started after the last deploy. |
| Manually mark stuck orders as processing. | Trace why the payment callback is not updating the order, and fix the handoff. |
| Install another caching plugin. | Measure where checkout time goes: PHP execution, queries or external API calls. |
Services
Start with a diagnosis. Stay for the engineering.
Three ways to engage. Prices shown are starting prices — complex WooCommerce problems are scoped after diagnosis.
Emergency fix
For urgent or complex production problems that need immediate investigation.
- Checkout, payment or order failures
- Fatal errors after updates
- Assessed by severity, availability and scope
Senior technical partner
Ongoing senior WooCommerce engineering for stores and agencies.
- Reserved engineering time
- Updates, reviews and technical decisions
- Escalation path for difficult problems
Specialist services
- Payment troubleshootingGateways, failed transactions, callbacks, webhooks, 3DS and order/payment mismatches. Scoped after diagnosis
- Checkout troubleshootingCheckout failures, AJAX problems, validation, guest checkout and payment handoff. Scoped after diagnosis
- WooCommerce performanceDatabase, PHP, caching, Action Scheduler, server and application performance. Scoped after diagnosis
- HPOS supportMigration, compatibility, custom code and order data issues. Scoped after diagnosis
- Custom developmentCustom functionality, integrations, APIs, webhooks and complex WooCommerce work. Scoped after diagnosis
Prices shown are starting prices. Complex WooCommerce problems are scoped after diagnosis.
Technical expertise
The whole stack. Not just the plugin layer.
WooCommerce problems rarely stay inside WooCommerce. The work covers the application, its data, the servers it runs on and everything it talks to.
Application04
- WordPress
- WooCommerce
- PHP
- JavaScript
Data05
- MySQL
- HPOS
- Redis
- Action Scheduler
- WP-Cron
Infrastructure04
- Nginx
- Apache
- PHP-FPM
- Linux
Network03
- Cloudflare
- DNS
- SSL/TLS
Integrations04
- REST API
- Webhooks
- Payment gateways
- ERP / CRM
Process
Diagnose. Explain. Fix.Test. Document.
-
01
Diagnose
Understand what is actually failing: reproduce, read the logs, isolate the layer.
output: reproduction + findings
-
02
Explain
Identify the root cause and explain it clearly before anything is changed.
output: root-cause explanation
-
03
Fix
Implement the appropriate solution in code, configuration or data.
output: scoped, reviewed change
-
04
Test
Verify the fix under realistic conditions — on staging first where possible.
output: verified flow
-
05
Document
Explain what happened, what was changed and how to prevent it.
output: written report
For agencies
Your senior WooCommerce technical partner.
Send the difficult client problems to an engineer who works at code, database and server level — without hiring another full-time developer. You keep the client relationship. We diagnose, fix and document.
- Client checkout broken
- Payment integration failing
- HPOS migration
- Custom plugin conflict
- Performance problems
- API integration
- Database issues
- Production emergency
Your agency
ClientWebsiteProjectProblem
WooRescue HQ
DiagnosisEngineeringFixDocumentation
The client relationship stays with your agency.
Knowledge base
Latest technical resources
- WooCommerce / Checkout WooCommerce Checkout Not Working: How to Diagnose the Root Cause First determine whether the failure happens before the checkout request, during it, or after the gateway response. The Network panel and PHP logs usually reveal which layer fails.
- WooCommerce / Payments WooCommerce Payment Failed but Customer Was Charged When the gateway captures the payment but the order stays pending or failed, look at the callback and webhook handoff before touching the order.
- WooCommerce / Orders WooCommerce Orders Missing or Incorrect Before assuming an order is lost, check every status, drafts and the payment provider. Incorrect totals usually come from tax settings, fees, coupons or recalculation.
- WooCommerce / HPOS WooCommerce HPOS: Common Problems With Custom Code Direct wp_posts queries, get_post_meta() on orders and other code that silently breaks once orders live in their own tables.
- WooCommerce / Performance WooCommerce Slow Checkout: What to Check Separate PHP execution time, database queries and external API calls before changing caching or hosting.
- WooCommerce / Errors WooCommerce Fatal Error: A Practical Troubleshooting Guide Read the fatal error properly — file, line, stack trace — and connect it to the change that triggered it.
FAQ
Questions before you send a problem
WooRescue HQ provides senior WooCommerce troubleshooting and engineering services for WooCommerce stores and WordPress agencies.
What does a WooCommerce technical diagnosis include?
A root-cause investigation of one specific problem. Where possible we reproduce the issue, review the relevant logs, code, plugins, configuration and data, and deliver written findings: what is failing, why, and the recommended fix with its scope. Diagnosis starts from €299.
Do I need to send passwords or server access?
No. Never send passwords, API keys, tokens or card data through the form. If access is needed once the problem is scoped, we agree on a secure method and the minimum access required.
How quickly can you work on an urgent problem?
Urgent technical issues are assessed based on severity, availability and scope. Describe the business impact in your request — for example, whether checkout is completely down — so it can be prioritised correctly.
Can you guarantee the problem will be fixed?
No honest engineer can guarantee a fix before understanding the problem. That is why work starts with a diagnosis: you get the root cause and a scoped recommendation before any larger fix is agreed.
Do you work with WordPress and WooCommerce agencies?
Yes. Agencies use WooRescue HQ as a senior technical partner for difficult WooCommerce work — checkout and payment failures, HPOS migrations, performance and integrations — while keeping their own client relationship.
Which WooCommerce problems do you work on?
WooRescue HQ diagnoses and fixes WooCommerce checkout, payment, order, HPOS, performance and integration problems, together with the PHP, JavaScript, database and server issues behind them.
$ describe the problem
Have a WooCommerce problem?Request a diagnosis.
Tell us what is failing, what changed recently and the business impact. We review every request and recommend the appropriate next step.
Request a diagnosis
See services and prices
Never send passwords, API keys or card data through the form.