Learn Base64

Published October 11, 2026

Base64 shows up in e-mail attachments, data URIs, JSON APIs, JWT tokens, certificates and configuration files. These short guides explain how it really works, with worked examples you can follow on paper.

Start with What is Base64?, then follow the algorithm step by step.

Saving data on metered mobile plans? Read Compress before Base64.

What is Base64? What Base64 encoding is, why it was invented, where it is used (e-mail, data URIs, JSON, JWT), why the output is 33% larger, and why it is not encryption. Base64 algorithm How the Base64 algorithm works: splitting bytes into 6-bit groups, the index table, padding with =, the output length formula and encoder/decoder pseudo-code. Base64 characters The 64 characters of the Base64 alphabet with decimal and 6-bit binary values, the padding character, and the Base64URL, IMAP and XML alphabets. More Background topics for understanding Base64: the ASCII table, related binary-to-text encodings (Base32, Base58, Ascii85, uuencode, hex) and how they compare. European character sets Decode Base64 text from Europe correctly: UTF-8 vs ISO-8859-1 (Latin-1), Windows-1252, ISO-8859-2 (Central Europe), ISO-8859-15 and Cyrillic sets. Fix mojibake like Ã©. AI agents How AI agents and MCP servers should encode/decode Base64, JWT and URL data. Principles to avoid LLM hallucinations, token bloat and double-encoding bugs. Bandwidth Why you should compress images and gzip text before Base64. Practical guide for Brazil, LATAM and anyone on prepaid data—plus private browser tools that never upload.

Comments (0)

Questions, ideas or a bug in “Learn Base64”? Leave a comment, rate the tool, or reply to others.

No comments yet. Be the first to share your feedback!