Notes from the people building Slip

Occasional writing about receipts, categories, and the parts of a money app that turn out to be harder than they look.

Notes from the people building Slip

Occasional writing about receipts, categories, and the parts of a money app that turn out to be harder than they look.

5 min

Reading crumpled paper

A drawer in the Lisbon office holds 4,182 receipts, one jar of them left in a car through a summer. 214 of them can no longer be read by anybody, which is a fact the reader has to live with.

Rui Cavaleiro

·

Machine learning engineer

6 min

Three days of watching people file receipts

Fourteen kitchen tables, one biscuit tin kept since 2011, and a shutter button in the wrong half of the screen. Most of what changed after the June visits had nothing to do with reading paper.

Nadia Okonkwo

·

User researcher

5 min

Running the reader on the phone

380 ms on an iPhone 14, 3.4 s on a Galaxy A13, and an import that Android kept killing at receipt 60. What it took to keep the reading on the device, and what it costs.

Marek Dudek

·

Mobile engineer

5 min

How we priced Slip

In March the price went from EUR 19 a year to EUR 29 and 1.9% of subscribers left. The reasoning behind both numbers, and the offer we turned down in 2025.

Elif Karabulut

·

Co-founder

4 min

No red numbers

A total set in red, an arrow pointing up, and a comparison against a month with a week away in it. Taking the judgement out of the interface was more work than putting it there had been.

Yuki Tanabe

·

Design lead

5 min

Sorting a supermarket receipt into one box

The first release had 41 categories and an “Other” bucket that swallowed 22% of everything within two months. What we changed, and the part no two households will agree on.

Priya Raghunathan

·

Product engineer

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