Developer Blog
Practical guides on JSON, UUIDs, timestamps, regex, QR codes, encoding, and other developer tools we build at RuMystic.
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Base64 vs Base64URL: what's the difference and when to use which
Base64 and Base64URL solve the same problem with two different alphabets. This guide explains the character differences, URL safety, padding rules, and when each encoding is the right choice.
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HSL vs HSV vs HSI: what's the difference and why it matters
HSL, HSV, and HSI are three color spaces that look similar but differ in how they compute lightness. This guide explains the math, shows when each is useful, and helps you pick the right one for your color picker or gradient tool.
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JSON5 vs JSON: what's the difference and when to use which
JSON5 extends JSON with comments, trailing commas, unquoted keys, and more. This guide covers the syntax differences, compatibility tradeoffs, and when JSON5 is the right choice over standard JSON.
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QR code error correction levels explained: L, M, Q, H
QR codes have four error correction levels — L (7%), M (15%), Q (25%), H (30%). This guide explains what they mean, when to pick which, and how they affect scannability and density.
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Regex lookahead and lookbehind: a practical guide with examples
Understand regex lookahead (?=) and lookbehind (?<=) with clear examples. Learn positive vs negative, fixed-width vs variable, and avoid the most common mistakes.
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Unix timestamp converter: seconds, milliseconds, microseconds explained
A practical guide to Unix timestamps — seconds vs milliseconds vs microseconds, how to convert between them, common bugs, and how to handle timezones when displaying them to users.
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UUID v4 vs v7: which one should you use in 2026?
A practical comparison of UUID v4 and UUID v7 — collision probability, sortability, database index impact, and when to pick which. Includes a free in-browser generator.