macOS formula notepad

Like =SUM
but for language.

🔒 100% on-device. Nothing leaves your Mac.

Type =apfel("summarize this") in your markdown. Watch it stream inline. No API keys. No cloud.

Download free View on GitHub
MIT Open Source macOS 26 Tahoe Apple Silicon
apfelpad showing inline formulas rendered in a markdown document
See it in action

Write formulas. See results inline.

Rendered view
apfelpad rendered view with inline math and AI formula results

=math(365*24) becomes 8760. =apfel() calls stream AI text. Both render as green spans.

Source view
apfelpad source view showing raw formula syntax in markdown

Toggle to see raw markdown. Formula syntax is plain text. Open in any editor.

How it works

Three steps. No setup.

1

Write markdown

Headings, bold, lists — it all renders inline.

2

Drop in a formula

=apfel(summarize this) or =math(365*24) anywhere in your text.

3

See results inline

Pale green spans. Cached. Reproducible via seeds.

The formulas

Seven functions. One syntax.

=apfel(prompt, seed?)
On-device AI call. Seed makes output reproducible.
=math(expression)
Pure arithmetic. No model. Instant.
=ref(@anchor)
Insert content from a named heading or block.
=count(@anchor?)
Word count of a section or full document.
=date(format?)
Current date, optionally formatted.
=clip()
Clipboard snapshot at evaluation time.
=file(path)
Local file contents. Sandboxed.
Install

Get apfelpad

Free. Signed and notarised. Apple Silicon only.

Download

Unzip, drag to Applications, open.

Download free (arm64)

Signed and notarised. SHA-256 in each release.

After installing

  1. Open apfelpad from Applications
  2. A welcome document opens with examples
  3. Click a green span to edit its formula
  4. Type =math(2+2) and press Return
Other install options

Homebrew

brew install Arthur-Ficial/tap/apfelpad

Updates with brew upgrade apfelpad.

Curl installer

curl -fsSL https://raw.githubusercontent.com/Arthur-Ficial/apfelpad/main/scripts/install.sh | zsh

Build from source

git clone https://github.com/Arthur-Ficial/apfelpad.git
cd apfelpad && make install
Features

A spreadsheet for prose.

Inline rendering

Results appear right where you type. No output pane.

100% on-device AI

No API keys. No cloud. Nothing leaves your Mac.

Deterministic seeds

=apfel("prompt", 42) gives the same output every time.

Cached results

Re-opening shows results instantly. Change the prompt to re-evaluate.

Auto-quoting

Type =apfel(hello world). The parser adds the quotes.

Plain markdown

.md files on disk. Open in any editor.

Under the hood

Powered by apfel.

apfelpad launches apfel (an OpenAI-compatible server for on-device Foundation Models) on localhost:11450 at startup. All AI inference stays on your Mac. apfelpad handles formula parsing, caching, context resolution, and inline rendering on top.

Requirements

What you need

macOS 26 (Tahoe)
Apple Silicon (M1+)
Apple Intelligence enabled
apfel on PATH

=math() works without AI. Only =apfel() formulas need the on-device model.

Privacy

One network call. Not for inference.

Optional update check via api.github.com (togglable in settings). Every AI call goes to localhost. No telemetry. No accounts. No cloud inference. Ever.

Free and open source.

MIT-licensed. Use it, fork it, ship it.

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