JSON Stringify Online - Escape JSON as a JS/JSON String
Updated
Properly escape a JSON document so it can be embedded as a single string value inside JavaScript or another JSON document. Fix quote and newline breaking—100% client-side, your data never leaves your browser.
Key Features
- ✅ Quote escaping
- ✅ Newline handling
- ✅ Double JSON.stringify() for nested-string embedding
- ✅ JavaScript safe strings
- ✅ Client-side only
How to Use
- Accept JSON input via textarea or file upload
- Parse JSON using JSON.parse() to validate
- Use JSON.stringify() to produce the base serialized form
- Apply a second JSON.stringify() pass to produce a JS/JSON string literal (no separate SQL-escaping mode exists)
- Handle Unicode and emoji correctly via UTF-16 surrogate pairs
- Show the escaped string, ready to paste into code
- All logic is client-side; no data leaves the browser
- Support copy/download of escaped output
Expert FAQ
- Isn't plain JSON.stringify() already escaped? Why does this add another layer?
JSON.stringify() produces valid JSON — its internal string values are already JSON-escaped. This tool's second layer is exactly one more JSON.stringify() pass, which is what you need to embed the whole blob as a JS string literal (JSON and JS double-quoted-string escaping are compatible). It does NOT perform SQL-style single-quote doubling, so the output is not made safe for a SQL string literal. - Does this actually prevent SQL injection?
No — this tool does not target SQL at all. It only performs JSON/JS-style backslash escaping (a second JSON.stringify() pass), which does not double single quotes the way a SQL string literal requires, so its output is NOT safe to concatenate directly into a SQL string. Always use parameterized queries/prepared statements with the unescaped JSON as the bound parameter for database code. - How does it handle Unicode characters and emoji inside the JSON values?
They're preserved correctly — JSON strings are defined over Unicode code points, and characters outside the Basic Multilingual Plane (many emoji) are represented as UTF-16 surrogate pairs per the JSON spec when escaped numerically; this tool follows that spec behavior rather than mangling multi-byte characters, which is a real failure mode in hand-rolled escaping code.
Technical Details
JSON.stringify() on its own produces valid, self-contained JSON — a string with correctly escaped internal quotes and control characters. The additional escaping this tool applies matters specifically when that entire JSON document needs to be nested as a single value inside a different host syntax: a JavaScript string literal in generated code, or a SQL string literal in a query. In both cases, the JSON's own already-escaped quotes need a second layer of escaping relative to the *outer* string's delimiter — this is legitimate double-escaping, not redundancy, and it's exactly the step a plain JSON.stringify() call doesn't perform because it has no concept of what context the result will be embedded in. This tool does not produce SQL-string-literal-safe output: it performs a second JSON.stringify() pass, which escapes quotes the JSON/JS way (backslash-escaping) rather than the SQL way (doubling a single quote), so dropping its output directly into a SQL string literal is not safe. Production database code should always pass the JSON as a bound parameter value via a parameterized query rather than concatenating escaped text into a query string. Unicode handling follows the JSON specification's own rules: code points outside the Basic Multilingual Plane (a large share of emoji) are represented as UTF-16 surrogate pairs when numerically escaped, matching how JSON.stringify() itself behaves in a spec-compliant engine — a detail that's easy to get wrong in hand-written escaping logic but is handled correctly here by relying on the platform's own JSON serializer as the base step. If you need to shrink the result further afterward for production use, the JSON Minifier or JSON to One Line are the next tools in the pipeline.