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The IO Tools Journal

Guides, deep dives and field notes on the tools, formats and protocols developers use every day.

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CryptographyFeatured

The Playfair cipher: why pairing letters actually worked

Caesar, Atbash and ROT13 all fall to counting letters. Playfair's one change — encrypting two letters at a time instead of one — was enough to make that attack useless. Here's the grid, the rules, and where it still breaks.

Sep 5, 20267 min
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Cryptography

The Vigenère cipher: the code that called itself unbreakable

Sep 2, 2026 · 7 min
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Databases

UUID versions explained: v4, v7, and ULID

Sep 1, 2026 · 4 min
close-up of blurred Python code on a dark terminal screen
Configuration

YAML vs JSON vs TOML: which config format should you actually use?

Sep 1, 2026 · 3 min
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Databases

Snowflake IDs: how Twitter and Discord pack a sortable ID into 64 bits

Aug 31, 2026 · 8 min
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Naming

Fáfnir, Smaug and Ao Guang Are Not the Same Kind of Name

Aug 24, 2026 · 5 min
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Naming

Almost Every Dwarf Name You Know Comes From One Norse Poem

Aug 24, 2026 · 6 min
three gold combination luggage locks with number dials on wooden surface
Naming

Harry Potter Names Are Latin Homework in a Cloak

Aug 24, 2026 · 5 min
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Naming

How Japanese Names Actually Work (And Why the Order Flipped Back)

Aug 24, 2026 · 6 min
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Naming

Skyrim Names by Race: What Actually Makes a Nord, Elf, or Khajiit Name Sound Right

Aug 24, 2026 · 6 min
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Naming

Where Surnames Come From (And Why Yours Is Newer Than You Think)

Aug 24, 2026 · 6 min
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Sports

Beyond batting average: unlocking advanced baseball stats

Aug 10, 2026 · 6 min
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Gardening

DIY landscaping: accurate area calculations for your garden

Aug 10, 2026 · 5 min