String Escape / Unescape

What each syntax changes

JSON escape runs JSON.stringify and removes the first and last character, which are the quotes the serializer added. A double quote becomes a backslash and a quote. A backslash is doubled. A newline, carriage return, or tab becomes a backslash escape. Other control characters become \u plus four hex digits. Ordinary text stays, including an apostrophe and the letters in café. The result is the inside of a JSON string. If you need a complete JSON value, add the quotes yourself. JSON unescape wraps the field in quotes and parses it, so \u0041 becomes A and a backslash-n pair becomes a real newline.

JavaScript escape doubles backslashes first, then prefixes a backslash to ' and to ", then replaces a real newline, carriage return, and tab with \n, \r, and \t. it\'s is the JavaScript spelling of it's. A backtick and a ${ sequence are not escaped. SQL escape replaces each ' with '' and then doubles backslashes. O'Brien becomes O''Brien. A double quote is unchanged. A newline stays a newline, so a SQL string that contains a line break is not folded into \n. SQL unescape collapses '' to ' first, then collapses paired backslashes.

Escape, Unescape, and the syntax menu

The mode buttons are Escape and Unescape, in a group labeled Escape mode. Syntax is a menu with JSON, JavaScript, and SQL. The placeholder in Escape is a sample with a quote and a newline hint. The placeholder in Unescape shows a backslash form. Placeholders are not loaded into the field. The field starts empty, and Run on an empty field succeeds with an empty result in every syntax and both directions.

The result label follows the mode: Escaped output or Unescaped output. Copy output copies that box. There is no download. The status line is the only place a failure is described. JSON is the syntax that can fail on unescape. JavaScript and SQL unescape are sequences of replacements, so they do not throw when the escapes are unbalanced. They still report Unescaped successfully.

Jobs for a quoted literal

Use JSON when the next paste is the inside of a JSON string in a fixture or a log. A full document, with indent, belongs on the JSON formatter after you have a complete value. Nested JSON that is still wrapped as a string belongs on JSON unescape, which decodes a JSON string value rather than only the escape rules in this field. This page will not pretty-print braces.

HTML entities such as " belong on HTML encode / decode. A \u escape of every character, including letters that JSON would leave alone, belongs on Unicode escape. JSON escape of café stays café. The Unicode tool would spell each character. A SQL statement that needs indenting, rather than a quoted literal, belongs on the SQL formatter. This page does not see SELECT or table names.

JSON errors and the JavaScript backslash order

JSON unescape of a raw quote fails because the added quotes no longer wrap one string. Unescape of He said "hello" in JSON clears the output and sets the status to Error: Unexpected non-whitespace character after JSON at position 10 (line 1 column 11). That sentence is the parser's message with Error: in front. A truncated \u or a stray backslash at the end fails the same way, with whatever message the parser returns. The previous success text is not kept.

JavaScript unescape applies \n, \r, \t, \", and \' before it turns \\ into a single backslash. A doubled backslash followed by the letter n is therefore read as a backslash plus a newline, not as a backslash plus n. Escaping a backslash and the letter n, then unescaping that result, does not return the original two characters. JSON does not have that ordering bug: its parser treats \\n as a backslash and the letter n. If the round trip must preserve a Windows path or a regex that contains \n as two source characters, use the JSON syntax, or check the JavaScript result before you paste it into code.

Rules and limitations

JSON escape is a JSON string body, without wrapping quotes. JSON unescape parses that body and accepts \u escapes. JavaScript escapes backslash, quotes, newline, carriage return, and tab. SQL doubles single quotes and backslashes only.

A failed JSON unescape clears the result and prefixes Error: to the parser message. JavaScript unescape can misread a doubled backslash before n. Empty input succeeds. Copy output copies the result. There is no download and no HTML mode.

Common problems

If SQL left a double quote untouched, that is the SQL rule. Only single quotes and backslashes change. Use JavaScript or JSON when the double quote must gain a backslash.

If a JavaScript round trip turned \n into a backslash and a real newline, the unescape order did that. Switch Syntax to JSON for a round trip that keeps the letter n.

Frequently asked questions

About this tool

Maintained by Toolbench. For large or deeply nested files, split the input into smaller batches and verify representative results before using them in an import or application. Report reproducible problems through Contact.