String Escape & Unescape — JSON, JS, HTML, URI, SQL

JSON when embedding a value into JSON. JS for template strings or inline strings in code. HTML for content injected into a page. URI for query params or path segments. SQL when building a literal by hand (though you should really use parameterized queries).

This tool only doubles single quotes — enough for a literal string in most SQL dialects, but NOT a substitute for parameterization or prepared statements in application code. Use it for one-off ad-hoc queries only.

JSON mode preserves Unicode as-is (JSON.stringify does not escape by default). JS mode does the same. HTML entity encoding covers the reserved 5 chars only; add numeric character references (&#…;) if you also need to encode arbitrary code points.