Base64 Encoder Online Free — Encode & Decode in Browser

Base64 encoding converts binary or text data into ASCII-safe characters. Developers use it for JWT payloads, data URIs, email attachments, and embedding small files in JSON. It is encoding, not encryption — anyone can decode it.

How to encode Base64 online for free

• Paste text into the Encode tab — Base64 output updates live
• Toggle URL-safe mode for JWT-style encoding (-_ instead of +/)
• Switch to Decode to reverse a Base64 string back to text
• Use round-trip to confirm encoding is correct before shipping

Standard vs URL-safe Base64

• Standard uses +, /, and = padding — fine for JSON and email
• URL-safe replaces + with - and / with _ — required in JWT segments and query strings
• JWT header and payload are URL-safe Base64 — not the same as standard

Common use cases

• Decode a JWT header or payload for debugging
• Encode credentials for HTTP Basic Auth
• Create data URIs for inline images in HTML/CSS
• Safely embed binary data in JSON APIs

Many online Base64 tools send your input to a server. For tokens, passwords, or proprietary data, use a client-side encoder instead — Utiliio processes everything in your browser.