The Person Who Knows Excel built a custom ERP for one department

“We'll migrate it eventually.”— Jens, The Person Who Knows Excel

Reason:

Officially because the integration works unless it is Monday. With 2 tests, all skipped.

Built by:

Jens, an analyst

Build time:

8 evenings

Built with:

an AI agent with shell access

Database:

the production database, directly, with write access

Authentication:

the logout button refreshes the page

Deployment:

deployed from a Git commit nobody has pushed

Responsible:

a contractor invoicing €738/day through a third party

Documentation:

a Confluence page linking to another Confluence page

Security situation:

there is one shared admin account

Future disaster:

It will stop working after someone renames a column.

Age: 4.8 years · originally expected to last 3 weeks · 1 owner so far · survived 1 reorganisation · last meaningful change 823 days ago

Rated common mostly because: alive 84x longer than intended, direct production access, 29 users.