PayPal Auto Premium Upgrade Integration

I run a PHP-based, custom-built site with its own membership table. Right now, every time someone pays for the premium plan through PayPal I still need to flip the “premium” flag in the database by hand. I want that step to happen instantly and reliably.

The job is straightforward: connect my PayPal checkout flow to our membership logic so that, once PayPal confirms a successful payment, the user’s record is updated to premium, the transaction ID is stored, and PayPal’s verification safeguards (IPN or Webhook with REST API—whichever you prefer) are respected. Our database schema is simple: users.id, users.status (free / premium), users.paypal_txn. No third-party membership plugins are involved; everything is custom.

Deliverables
• PHP script(s) that receive and validate PayPal’s notification
• Secure update of the user’s status and storage of txn ID
• Success / failure logging I can read in plain text
• A brief README showing where to drop the files and which PayPal settings to enable

Acceptance criteria: after a sandbox test payment, the test account must automatically switch to premium without manual intervention, and the log should show the verified transaction details.

That’s it—clean, reliable, and easy for me to maintain.