TextTools Online
Count words, change case, encode text, compare two versions, and create placeholder copy or passwords.
These tools work on text that has already been written. Most of them update the result as you type. Two of them create text rather than change it: placeholder copy for layouts, and passwords.
Password Generator is also listed with IT-Network Tools. JSON Formatter is also listed with the developer tools.
Text Tools
Word Counter
Counts words, sentences, and paragraphs, and estimates reading time.
Character Counter
Counts characters and lists the most frequent letters.
Word Scrambler / Descrambler
Mixes letters, and finds words that can be made from a set of letters.
Case Converter
Changes the capital letters in a passage.
URL Encoder / Decoder
Encodes characters that would break a web address.
Base64 Encoder / Decoder
Turns text or a file into plain characters, and back.
JSON Formatter / Validator
Checks and formats JSON. Also listed with Developer Tools.
Lorem Ipsum Generator
Produces placeholder copy by paragraphs, sentences, words, or bytes.
Password Generator
Produces strong passwords. Also listed with IT-Network Tools.
Markdown Previewer
Shows Markdown as it will appear, including tables and code.
Text Diff Checker
Compares two versions and marks each change.
String Reverse
Flips text by character, by word, or by line.