WooCommerce & API Integration Developer

Freelance/Contract Role: WooCommerce & API Integration Developer (Stripe, QuickBooks, Automation)
Project Overview
We are looking for an experienced developer to rebuild and stabilise the checkout and post-purchase workflow for our WordPress/WooCommerce website.

Our current setup relies on a combination of WooCommerce, Stripe, and Zapier to handle digital delivery, bookkeeping, and CRM triggers. However, the current workflow is fragile, occasionally fails to sync, and lacks the robust error handling we need. We want to streamline this pipeline—potentially moving away from fragile multi-step Zapier Zaps toward direct API integrations or a highly reliable, webhook-driven architecture.

Current Tech Stack
CMS: WordPress + WooCommerce

Payment Gateway: Stripe

Accounting: QuickBooks Online

Automation/CRM: Zapier (currently used, open to better alternatives/direct webhooks)

Key Requirements & Workflow Logic
The successful candidate will implement and test a bulletproof system that executes the following workflow flawlessly upon every successful transaction:

1. Payment Processing (Stripe)
Process the transaction securely via Stripe through WooCommerce.

Ensure strict handling of payment success webhooks (payment_intent.succeeded or charge.succeeded) so subsequent actions only trigger on verified funds.

2. Digital Fulfillment (PDF Delivery)
Instantly generate/retrieve the purchased PDF document and email it to the client as an attachment or secure download link upon payment verification.

3. Automated Bookkeeping (QuickBooks Online Integration)
Create a line-item invoice/sales receipt in QuickBooks Online for the exact amount paid.

Accurately calculate and reflect VAT/sales tax as processed in WooCommerce.

Prevent duplicate invoice creation through robust item/customer matching logic.

4. Data Logging & Order Tracking
Securely record full purchaser details (Name, Email, Company, Billing Address) and order specifics (SKU, Date, Order ID, Revenue) into a centralized, easily filterable tracking system (either native WooCommerce logs or a dedicated database/CRM).

5. Post-Purchase Email Drip (Drip Marketing/Retention)
Trigger an automated, staggered follow-up email sequence to the purchaser:

Email 1: Sent exactly 7 days post-purchase.

Email 2: Sent exactly 14 days post-purchase.

Note: Please advise on whether it is best to handle this via cron jobs, Stripe/WooCommerce native scheduling, or a dedicated transactional email API (e.g., Mailgun, SendGrid) to guarantee deliverability.

Technical Priorities
Error Handling & Idempotency: The system must handle network timeouts or API downtime gracefully. If a QuickBooks sync fails, it must queue and retry without re-sending the PDF or breaking the checkout experience.

Data Consistency: The numbers in WooCommerce, Stripe, and QuickBooks must match perfectly on every single transaction down to the penny.

Maintainability: Code must be clean, commented, and adhere to WordPress/WooCommerce development best practices.

To Apply,

DO NOT contact me through any other medium other than PPH; otherwise, you will be instantly rejected.

Please Provide:
Examples of custom WooCommerce API integrations you have built (specifically involving QuickBooks or Stripe webhooks).

Your preferred architectural approach for this project (e.g., keeping Zapier but optimising it, writing a custom WordPress plugin, or using webhooks with a dedicated middleware/mailer).

Your estimated timeline and cost for implementation and testing.