Base64 Decoder & Encoder Online — Free

Most online Base64 tools send your input to a server. That's a problem when you're decoding JWT tokens, API keys, or auth headers. decode64.com runs entirely in your browser using native JavaScript — nothing is ever uploaded. Paste your Base64 string and get the result instantly. → Decode Base64 to text → Encode text or any file to Base64 → Supports Base64URL (JWT tokens with - and _) → Drag & drop file support → Copy to clipboard, swap input/output