Guides to the formats behind the tools
8 reference pages, each answering one question: which UUID version, which hash, which cron dialect. Every number is either computed by a script, with the method stated, or read from the specification the page links to.
Last updated Published by Hyperdusk Ltd
UUID v4 vs v7: Differences and Which to Use
UUID v4 is 122 random bits with no order. UUID v7 starts with a 48-bit Unix timestamp in milliseconds, followed by 74 random or counter bits, so newer values sort after older ones. Use v7 for database keys that benefit from ordered inserts, and v4 when an ID must not reveal when it was created.
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UUID vs ULID vs Nano ID: Size, Sorting and Collisions
A UUID is a 128-bit identifier standardised in RFC 9562 and written as 36 characters. A ULID is also 128 bits, with a millisecond timestamp first, written as 26 characters. A Nano ID is a random string, 21 characters by default, carrying 126 random bits. UUID v7 and ULID sort by creation time; UUID v4 and Nano ID do not.
Related tool:UUID Generator
Password vs Passphrase: Which Is Stronger?
Neither is stronger by nature. Strength is the number of equally likely results the generator could have produced. A random 12-character password drawn from the 94 printable ASCII characters carries 78.7 bits of entropy; a random six-word passphrase from the EFF large wordlist carries 77.5. The passphrase is longer but easier to type and remember.
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MD5 vs SHA-1 vs SHA-256 vs SHA-512: Which Hash to Use
MD5 and SHA-1 are broken for collision resistance: different inputs with the same digest have been produced for both. SHA-256 and SHA-512 are NIST-approved, with 128 and 256 bits of collision resistance. Use SHA-256 for checksums and signatures. Use none of the four to store passwords, which needs a slow function such as Argon2id or bcrypt.
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Static vs Dynamic QR Codes: What Is the Difference?
A static QR code holds the final content itself, such as a full URL, so it works for as long as that content does and cannot be edited after printing. A dynamic QR code holds a short link run by a QR service. The link redirects to a destination you can change later, and the service counts scans.
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HEX vs RGB vs HSL vs OKLCH: CSS Color Formats Compared
HEX and rgb() say the same thing: amounts of red, green and blue in sRGB. hsl() rearranges those into hue, saturation and lightness, which is easier to adjust by hand. oklch() uses perceptual lightness, chroma and hue, so equal lightness values look equally light, and it can describe colors outside sRGB.
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Cron Syntax Compared: Unix, Quartz, AWS, GitHub Actions
Unix cron uses five fields: minute, hour, day of month, month and day of week. Quartz adds a seconds field at the start and an optional year at the end. AWS EventBridge uses six fields with the year last and no seconds. GitHub Actions uses the five-field form, in UTC by default. The dialects also number weekdays differently.
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HS256 vs RS256 vs ES256: JWT Signing Algorithms
HS256 signs a JWT with one shared secret, so every party that can verify a token can also create one. RS256 and ES256 sign with a private key and verify with a public key. RS256 uses RSA and produces a 256-byte signature with a 2048-bit key. ES256 uses the P-256 elliptic curve and produces a 64-byte signature.
Related tool:JWT Decoder & Encoder
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