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URL / Base64 / HTML Encoder

Six encoding formats, instant two-way conversion: **URL** (encodeURI), **URI component** (encodeURIComponent), **Base64** (standard padding), **Base64URL** (JWT / OAuth), **HTML entities**, **Unicode escape** (`\uXXXX`). Pure frontend.

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›How to use
  1. Choose Encode or Decode, then pick one of 6 formats.
  2. Type / paste a string on the left — the right side updates instantly, no button to click.
  3. Hit ↕ Output → input to flip the result back into the input — perfect for round-trip sanity checks (encode → decode = original).
  4. Copy the output to clipboard, ready to paste into curl, Postman, or a URL bar.
Tips
  • URL vs URI component — encodeURI preserves :/?#&=, use for full URLs; encodeURIComponent escapes everything, use for query-string values.
  • Base64 vs Base64URL — JWT, OAuth state and URL-safe cookies use Base64URL (+/= → -_ with no padding). Mail attachments use standard Base64.
  • HTML entities decoder accepts named (&), numeric (') and hex (中) forms; encoder only escapes the canonical 5 (& < > " ') to avoid over-escaping.
  • Unicode escape auto-picks BMP (\u4e2d) vs astral plane (\u{1f30d} for emoji).

💡 Pure functions over the built-in browser APIs — no extra deps, zero bundle increase. Works offline.

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