Base64 Encoder / Decoder

Base64 turns arbitrary bytes into a safe alphabet of letters, digits and a couple of symbols, which is why it shows up anywhere binary data has to travel through text-only channels: data URIs, HTTP basic auth headers, email attachments, JSON payloads, JWT segments and certificate files.

This tool converts in both directions instantly as you type. It handles full UTF-8 — emoji, accented characters, CJK scripts — correctly, where naive btoa() implementations break. The URL-safe variant (replacing + and / with - and _) is one toggle away, which is what you need when stuffing Base64 into query strings or working with JWTs.

Common uses: decoding an Authorization header to check credentials, embedding a small image as a data URI, inspecting an opaque API blob, or encoding configuration secrets for a Kubernetes manifest. Everything runs locally in your browser — nothing you paste here is ever transmitted, stored or logged anywhere.