Plain-text notes you'll still be able to open in 2040

If you want your notes to be readable in 2040, the answer is boring and reliable: keep them as plain-text files in an open format — which today means Markdown. Not because it’s fashionable. Because plain text is the only document format with a fifty-year record of outliving every tool that ever wrote it.

Apps are mortal. Your notes shouldn’t be.

Every notes app you’ve ever loved will eventually be acquired, pivoted, subscription-walled, or quietly shut down. That’s not cynicism, it’s just software economics. The question that matters isn’t which app survives — nobody knows — it’s what happens to your notes when one doesn’t.

If your notes live in a proprietary database, the answer depends on an export button working correctly, before the servers go dark, in a format something else can actually read. That’s three conditions, and you control none of them.

If your notes are .md files in a folder you own, the answer is: nothing happens. You open them with whatever exists in 2040.

What actually makes a format survivable

Three properties, and Markdown has all of them:

1. It’s just text. A Markdown file is bytes any text editor since the 1970s can display. There is no importer, no runtime, no “supported version.” We tested exactly this claim: the same .md file, read by three unrelated programs — cat, vim, and a two-line Python script. Identical content, zero translation. file reports it as what it is: plain text.

2. It’s openly specified. Markdown isn’t one company’s file format — it’s a public, versioned specification (CommonMark, currently 0.31.2, CC-licensed with a full archive back to 2014). Anyone, forever, can write a compliant reader from the spec alone. No vendor has to survive for the format to.

3. It’s too widespread to rot. Markdown is the format of virtually every README on earth — hundreds of millions of them on GitHub alone — most developer documentation, and, increasingly, what AI assistants read and write natively. Formats die from abandonment. This one is load-bearing for the entire software industry.

The receipts

Claims about durability should be checkable today, so here’s the two-minute version you can run yourself:

$ file notes.md
notes.md: ASCII text

$ git diff          # after changing one word
-Markdown stays readable in modern editors.
+Markdown stays readable in any editor.

$ git diff --stat
 notes.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

One word changed, one line in the diff. Your edit history stays legible for as long as you keep the folder — which is also why plain text is the only note format that genuinely works with version control. (If you’ve ever watched an editor rewrite your whole file to change one word, that’s the other half of this story: your Markdown editor shouldn’t rewrite bytes you didn’t touch.)

How the formats compare

	Plain-text Markdown	Proprietary app format	Word-processor file
Readable without the original app	Yes — any text editor	Rarely (needs export first)	Partially (needs compatible software)
Openly specified	Yes (CommonMark)	No	Nominally, but enormous
Meaningful `git diff`	Yes — line-level	No	No
Survives the vendor disappearing	Yes	Only if you exported in time	Usually, with degradation

Moving your notes toward 2040

You don’t need to migrate everything this weekend. Directionally:

Keep new notes as .md files in a folder you control — local disk, synced however you like. The folder is the database.
Prefer tools that store notes as files rather than inside an opaque library you’d need to export from someday.
Test your current app’s export today, while it’s alive and you’re calm. If what comes out isn’t plain text you can open and diff, you’ve learned something important early.

Constly’s part in this is deliberately small: it’s a free Mac editor that renders your Markdown beautifully while it stays exactly what it was on disk — plain text, in your folder, yours. If your notes ever outgrow us, they walk away intact. That’s the point. Download it free, or start even simpler: make a folder, create 2040.md, and write the first note you’ll still be able to open when it matters.