The Lemnly Notebook

Field notes on memory, language, and building the tool we wanted.

Long-form essays, short observations, and the occasional engineering teardown. New issues every other Tuesday.

An open book on a wooden surface, warm side light
Methodology
The URL import workflow: how to mine your reading list for vocabulary
Methodology · 10 min read

The URL import workflow: how to mine your reading list for vocabulary

Most of us read more online than offline. Here is the exact workflow for turning the articles you already read into a quietly compounding vocabulary engine — using URLs as the primary input.

SW
Sebastian Walter
Founder, Lemnly
May 14, 2026
A leather-bound notebook beside a laptop, warm light from the side
Learning science
Why spaced repetition actually works — and how to use Lemnly to ride it
Learning science · 14 min read

Why spaced repetition actually works — and how to use Lemnly to ride it

Forgetting is not a bug. It is the signal a good scheduler needs to keep your vocabulary alive. Here is the science, the misconception most apps make, and the daily routine that turns SRS into a genuine superpower.

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Sebastian Walter
Founder, Lemnly
April 12, 2026
A pair of hands holding an open paperback book, soft daylight
Methodology
Reading is the cheat code. Here is how to use Lemnly to ride it.
Methodology · 12 min read

Reading is the cheat code. Here is how to use Lemnly to ride it.

Comprehensible input is the most underrated tool in second-language learning. A practical, step-by-step playbook for turning everything you read — books, news, Substack — into a vocabulary engine.

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Sebastian Walter
Founder, Lemnly
March 28, 2026
A wall of shelved books in a library, spines facing out
Research
How many words do you really need? The vocabulary thresholds, by language
Research · 14 min read

How many words do you really need? The vocabulary thresholds, by language

Fluency is not a number, but coverage is. A field guide to the vocabulary sizes that unlock conversation, reading and television in 12 languages — and a roadmap for getting there with Lemnly.

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Sebastian Walter
Founder, Lemnly
March 4, 2026
An open book with sunlight falling across its pages
Learning science
Reading the forgetting curve like a chart, not a verdict
Learning science · 8 min read

Reading the forgetting curve like a chart, not a verdict

A short essay on what the forgetting curve actually tells you — and the daily Lemnly routine that turns it from an enemy into an ally.

SW
Sebastian Walter
Founder, Lemnly
February 18, 2026
A stack of paperback books on a wooden surface
Product
Switching from Anki to Lemnly: an honest migration guide
Product · 11 min read

Switching from Anki to Lemnly: an honest migration guide

Anki is the gold standard for a reason. Here is when it makes sense to switch, what you keep, what you give up, and the exact 30-minute migration process — including how to import your URL backlog and your photo backlog in the same week.

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Sebastian Walter
Founder, Lemnly
January 22, 2026
A book and a cup of tea on a wooden table, warm afternoon light
Engineering
How a shared vocabulary cache makes AI labelling almost free
Engineering · 9 min read

How a shared vocabulary cache makes AI labelling almost free

Why the second person to import Il Gattopardo pays a fraction of a cent — and how that compounds across millions of articles, books, and URLs.

SW
Sebastian Walter
Founder, Lemnly
January 8, 2026

The article you’d normally skim?
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