Regex without guesswork
The Regex Tester lists every match with its index and capture groups, using the same JavaScript engine your browser code runs on. That makes it easy to confirm a pattern before putting it in a validator or a search-and-replace.
Seeing changes clearly
Text Diff compares line by line and marks additions and removals. It is useful for comparing two versions of an environment file or spotting what changed in a pasted log.
