Base64 Encoding Explained for Developers

Base64 encoding converts binary data into ASCII text using 64 printable characters. It's everywhere in web development — from data URIs to JWT tokens to email attachments.

When to Use Base64

- **Data URIs** — Embed small images directly in HTML/CSS. - **API authentication** — Basic auth headers use Base64-encoded credentials. - **JWT tokens** — Header and payload are Base64url-encoded JSON. - **File transfer** — Encode binary data for text-based protocols.

Base64 Is Not Encryption

This is critical: Base64 is encoding, not encryption. Anyone can decode a Base64 string instantly. Never use Base64 alone to protect sensitive data.

Encoding vs Base64url

Standard Base64 uses +, /, and = characters. Base64url (used in JWTs) replaces + with -, / with _, and often omits padding. StackSutra's JWT decoder handles both formats.

Try It

Use StackSutra's free Base64 Encoder and Decoder — all processing happens locally in your browser.