Mittens II : The Reckoning
Type in either the Normal Text or Encoded Text boxes - everything will update as you type.
If the Encoded Text is invalid, the box will turn red and the Normal Text will not update until the encoded value is correct again.
Note this tool treats the input as a URI component, not the entire URI. Therefore you should only put a parameter into this tool, not the entire address.
For more details, check out the post