Skip to content
Here Be Dragons

Here Be Dragons

Notes from the edges of the map, where software gets strange, complex, and occasionally bites.

Start with Topics for evergreen reference, or Posts for dated write-ups.

Where the name comes from

“Here be dragons” is a phrase used since the Middle Ages to mark regions of a map a cartographer didn’t understand. Its only confirmed historical appearance is on the Hunt–Lenox Globe (c. 1508), the third-oldest known terrestrial globe, inscribed near the eastern coast of Asia with the Latin “HIC SVNT DRACONES”, literally “here are dragons.” Earlier medieval maps used the related phrase “HIC SVNT LEONES” (“here are lions”) to mark uncharted territory.

The actual practice was less about mythical beasts than about honest humility: a cartographer drawing the known world had to decide what to do with the parts they hadn’t been to, hadn’t been mapped, or had only third-hand rumors about. Here be dragons was a way of saying: “I don’t know what’s here. Tread carefully.” The Hunt–Lenox Globe now lives at the New York Public Library; you can still see the phrase right where the mapmaker ran out of certainty.

Why software borrowed it

Programmers have picked up the phrase as a comment for the same reason:

# HERE BE DRAGONS
# This function is load-bearing in ways we don't fully understand.
# The three call sites below depend on the exact order of the
# side effects. Before refactoring, read the 2023 outage postmortem.

A here be dragons comment marks a region of a codebase where:

  • The logic works, but nobody fully understands why.
  • The next person will break it if they refactor without reading the history.
  • The constraint isn’t visible in the code itself; it lives in an incident report, a regulation, a race condition, or a performance cliff that doesn’t surface in tests.
  • Modifying it has unforeseen consequences that ripple into parts of the system the author doesn’t know about.

It’s the opposite of clean-code bravado. It’s a cartographer’s note: I mapped this as well as I could. Don’t assume the map is the territory.

What this site is

A place to sketch those parts of the tech landscape I’ve been wandering through, the ones that fit in textbooks, and the ones that only show up when a system is already running and something breaks.

  • Topics, evergreen, categorized reference entries. Things like Kubernetes, RAG, the vehicle-routing problem, SOLID principles, HIPAA compliance. Written to still be useful a year from now.
  • Posts, dated write-ups. What I learned this week, notes from a project, patterns pulled out of real code.

Plain markdown throughout, so the same source renders on GitHub, on this site, and in a cross-post on dev.to or LinkedIn.

The repo

Source and history at github.com/waggertron/tech-learning. Contributions, corrections, and dragons welcome.

Why the name "Here Be Dragons"?