Three defences for a small online shop, with tests and a plain handbook. Check every payment message with the payment company before you deliver, stop two simultaneous orders wiping each other out, and upload your site over encrypted FTP with a one command undo.

What you get

• 62 automated tests: 26 in Node, 20 in Python and 16 in PHP.
• A payment verifier that never believes a webhook: it asks the payment company what really happened and compares it with your price to the cent.
• An order file lock for Node and PHP, proven with 24 real processes hitting it at the same instant.
• An encrypted deploy runner with check, deploy, verify and rollback.
• A quick audit tool, 13 sample webhooks, 8 deliberately bad files and a plain handbook: 4 short chapters with copy and paste steps.

Good to know
The PayPal adapter is an example and has not been tested against live PayPal. The audit tool is a pattern check, not a security audit. The deploy runner uses FTP over TLS and cannot use SFTP. The file lock is for a single server. Tested on Node 24, Python 3.12 and PHP 8.3; Node 20 or newer is required for the Node parts.

These kits are guidance and tools. They are not a guarantee against every attack.

FAQ
Is this a subscription? No. One payment, no renewals.
Where do I get the files? They are in the Files area of this product once you have bought it.