Base64 Encoder converts any text — plain ASCII, UTF-8, JSON, or emoji — into Base64 as defined by RFC 4648. Base64 encodes three bytes as four printable ASCII characters using the alphabet `A–Z a–z 0–9 + /`, with `=` padding, so binary data can travel through channels that only accept text (email headers, JSON strings, Data URIs, JWT payloads). We also support the URL-safe variant (`+` replaced with `-`, `/` replaced with `_`) used in JWTs and modern OAuth flows. Because the encoder uses `TextEncoder` under the hood, it handles UTF-8 correctly: multi-byte characters like `€` (3 bytes) or `😀` (4 bytes) round-trip cleanly, unlike older `btoa()`-only tools that break on non-ASCII input. Everything runs in your browser, so credentials, tokens, and confidential JSON never leave your device.
Free, fast, and runs entirely in your browser — no signup, no upload to a server.