Why URLs Contain %20: Encoding, Decoding and Other Everyday Mysteries

A copied URL full of %20, Chinese text turned into boxes, developers saying Base64 and UUID — these 'encodings' look arcane but each solves one small, concrete problem.

URL Encoding: Making Special Characters Travel Safely

Spaces, Chinese characters and & have special meaning inside URLs, so they get rewritten as % followed by hexadecimal: a space becomes %20, and 'zhong' becomes %E4%B8%AD. A wall of percent signs is usually just encoded Chinese — nothing is broken.

Number Bases: Computers Only Know 0 and 1

• Binary (0/1) is the machine's native tongue; hexadecimal (0-9/A-F) is the human shorthand — one hex digit maps to exactly four binary digits.
• Colors like #FF5733, memory addresses and MAC addresses are all hexadecimal under the hood.
• Converting between binary, octal, decimal and hex is a daily debugging move.

Garbled Text: Writer and Reader Used Different Dictionaries

Text is stored as numbers; which code table (encoding) translates it decides what you see. A file written in one encoding and opened with another produces mojibake — those boxes. Converting the characters to Unicode code points reveals the original instantly.

Two Frequent Supporting Actors

• Base64: turns any data into plain ASCII for safe transport; often ends with '='. It is encoding, not encryption — zero secrecy.
• UUID: a 128-bit random identifier like 550e8400-e29b-41d4-a716-446655440000. Collision chance is negligible — ideal for database keys and test fixtures.

FAQ

Can I store passwords in Base64?

Absolutely not — anyone can decode it; it equals plaintext. Passwords need proper one-way hashing.

Does Morse code still matter?

Rarely for daily use, but SOS (···---···) remains an international distress signal, and ham radio keeps it alive. A translator is handy for learning and games.