Product Founding Engineer
An app idea, shipped end to end
Newsletter system
A newsletter should not
cost you a day.
Curating the links, writing the summaries, wrestling the email template, checking it survives Outlook. Open-source, self-hosted, and running end to end on European infrastructure for about €5 a month.
The idea
What a newsletter looks like when the assembling is done for you
This one was not built for a client. It started as an ordinary problem, the hours that vanish into a weekly issue, and became a template anyone can run. Forty seconds:
The problem
A weekly issue eats a working day
Reading everything worth reading. Deciding what makes the cut. Writing a line on each so people understand why it matters. Then building the email, then checking it does not fall apart in Outlook. The interesting part, having something to say, turns out to be the smallest part of the day.
Curation
From reading everything to reading what matters
Before
Mornings disappear into a scroll through dozens of feeds, tabs left open all day, and the nagging feeling that the good one got missed anyway.
After
A job at five in the morning reads every source on the list, translates anything published in another language, sorts it into sections and scores it against the beat. By the time you sit down, the shortlist is waiting, and reading is back to being the enjoyable part.
Voice
It learns how you write, in plain English
Before
Generic AI copy that sounds like every other automated newsletter, with no way to fix it short of rewriting each issue by hand.
After
Every time you ask for a redraft, you leave a note. On Sunday night those notes are distilled into permanent editorial rules: ordinary sentences in a file you can open and edit. No fine-tuning, no black box. After a month or so, it sounds like you.
The editorial loop · interactive
Watch a week of notes turn into permanent rules
Every regenerate note written during the week feeds a Sunday job that distills the lot into editorial rules: plain English, in a Markdown file you can read and edit.
This week · 5 regenerate notesnotes-2026-w25.txt
- Too US-centric: we cover EU regulation primarily.
- Lead with the regulation angle, not the company name.
- Avoid hyperbolic words like "unprecedented".
- Section names should describe the area, not the abstract idea.
- Keep editorial notes under two sentences.
Editorial ruleseditorial-rules.md
Empty until Sunday 23:00.
Rules accumulate over time: readable, editable, yours.
Rules accumulate over time: readable, editable, yours.
A live mock of the real Sunday job. Plain-English rules, stored in a Markdown file you can read and edit.
A day in the life
Four crons, one editorial loop
Once the guided setup has run, the system works four scheduled jobs on its own. You press one button per issue, on the days you feel like it.
05:00
Daily fetch
Pulls every RSS feed on your list. Mistral translates anything outside your newsletter's language, categorises each article into your sections, and scores it for relevance to your beat.
Mistral · RSS07:00
Draft preview
Composes the issue (subject line, intro, glossary, and a one-line editorial note per article) and emails a preview to you with three buttons: Regenerate, Send Now, or Discard.
MJML · 3-button preview08:00
Dispatch
If you clicked Send Now, the issue goes out immediately. If you didn't click anything, the dispatcher auto-sends an hour after the preview. The system never sends without your button or that timeout, and never sends twice.
Brevo · idempotentSun 23:00
Editorial distill
Reads the week's regenerate notes and distills them into permanent, plain-English editorial rules. Stored in a Markdown file you can read and edit. After four to six weeks, the newsletter sounds like you.
Markdown · permanentWho builds it
Crystallized Intelligence
An AI consultancy in Luxembourg run by Aisling McCaffrey. EU-based and GDPR-first by default, so your data and your subscribers' data stay on sovereign, EU-hosted infrastructure. For the wider picture, see the practical guide to AI in Luxembourg.
More work
Other things built end to end
A newsletter you own outright.
The template is free after a fifteen-minute conversation. Setup takes about an hour, most of it spent waiting on DNS and function builds.