I have written many web applications for my own use, where I do not have to take the extra effort to bulletproofing applications for unintended use (validation

I have written many web applications for my own use, where I do not have to take the extra effort to bulletproofing applications for unintended use (validation and verification requirements etc). Three applications stand out: 1) a web application to manage customer Q-tagged VLAN Ethernet circuits within specific color-coded optical fibers of municipal fiber-to-the-home cables (12, 36, 48 and 96 fiber cables). The application enabled fiber optic physical plant to be optimized for customer Ethernet circuits, reducing the cost of implementing customers considerably below industry average. 2) a double-entry bookkeeping system optimized for the monthly US Bankruptcy Court Chapter 11 financial reporting requirements to manage the same company as debtor-in-possession when our largest customer(s) filed bankruptcy during the dot com bust (circa 2001), forcing us to also file for protection. This enabled us to successfully double our customer base, double our revenue and retire all debt while reorganizing in bankruptcy. 3) a general accounting web application emerged from these experiences specializing in multi-currency accounting of businesses specializing in asset management (features that Quickbooks etc just do not have). This built on my personal situation of being a citizen of more than one country. All 3 of these were developed using PHP/MySQL and I have refactored them over the decades up to PHP ver 8 / MySQL ver 8 running on the latest Ubuntu LTS server version. As I am the sole user (with a few personal assistants), I have been able to focus on the addition of features and capabilities rather than user support, security and general hardening of the applications.