About
Who writes this,
and how it gets checked
Who
My name is Jaesung Lee. I am a Korean office worker, currently on parental
leave. I am not a developer and never have been. I spent years rebuilding the same reports by
hand, and I learned regular expressions the way most people in an office do: by copying a
pattern off the internet, pasting it into a cell, and getting #REF! — an error
about broken references, for a formula that referenced nothing.
You can reach me at agentbuilder43@gmail.com. If something on this site is wrong, that address gets read.
How
The articles are written by Claude, an AI model made by Anthropic. I decide what gets covered, I run the verification, and I publish. That is the whole arrangement, and there is no version of this page where it is hidden in a footer.
I am telling you this because it changes what you should demand of the site. An article written by a model is worth exactly as much as the checking behind it. So here is the checking:
- Every formula that appears on this site is written into a real Google Sheet through the Sheets API, and the value Google computes is read back.
- That value — not a prediction of it — is what gets published. Where we did not know the answer in advance, the row is marked observed rather than dressed up as a finding.
- The run is saved with its date, the spreadsheet's locale, and the exact case file it ran. A checksum ties the two together.
- If anyone edits a formula after it was verified, the checksum stops matching and the site refuses to build. There is no way to publish a formula that has not run.
You can read the logs yourself: the RE2 limits run is the first one. The dates, the failures, and the surprises are all there.
Why
Because the internet is now full of pages that explain Google Sheets regular expressions without anyone ever having opened a spreadsheet. They are fluent, confident, and wrong in the same three places, because they were all assembled from the same documentation by writers who never ran a cell.
A model can produce that kind of page in seconds. It cannot produce an execution log. That gap is the only thing this site has, and protecting it is the only editorial policy that matters here.
How this is paid for
Display advertising, and nothing else. There is no course, no membership, no consulting, no affiliate link. When ads appear they will be labelled, they will never be dressed up as content, and their number will not go up because traffic went down.
What this site is not
- Not affiliated with, endorsed by, or connected to Google.
- Not for developers. If you write code for a living, Google's RE2 documentation is faster.
- Not a place to learn regular expressions from scratch. It is a place to find out why yours broke.