JSON Multiline Strings: Newlines, Escaping, and Alternatives

Standard JSON has no triple-quoted or raw multiline string syntax. A literal line break inside a quoted JSON string is invalid. Encode the line break as \n, or choose a different data shape.

Valid JSON:

{
  "message": "First line\nSecond line\nThird line"
}

After parsing, the message value contains real newline characters. The JSON source contains the two-character escape sequence \n.

Why a raw multiline string fails

This is not valid JSON:

{
  "message": "First line
Second line"
}

JSON strings must escape control characters. A parser will report an unterminated string, an invalid control character, or another syntax error near the line break.

Common newline escapes

Escape	Meaning
\n	Line feed; the usual newline
\r	Carriage return
\t	Horizontal tab
\\	Literal backslash
\"	Literal double quote

Windows text commonly uses carriage return plus line feed (\r\n). Most cross-platform application text can use \n internally and let the display or file layer choose platform-specific line endings.

Use the JSON escape tool or JSON unescape tool when you need to inspect or generate escaped text.

Let a serializer escape the string

Avoid building JSON by concatenating quoted strings. Native serializers handle newlines, quotes, tabs, and backslashes correctly.

JavaScript:

const message = `First line
Second line`;

const json = JSON.stringify({ message });
console.log(json);
// {"message":"First line\nSecond line"}

Python:

import json

message = """First line
Second line"""

payload = json.dumps({"message": message})
print(payload)
# {"message": "First line\nSecond line"}

The source-language string can span lines even though the serialized JSON string cannot contain unescaped line breaks.

Use an array when lines are separate items

If order matters but each line has its own meaning, an array is often clearer:

{
  "addressLines": [
    "123 Example Street",
    "Suite 400",
    "New York, NY 10001"
  ]
}

Arrays make it easier to add, remove, validate, and render individual items. Join them with a newline only at the presentation layer:

const formattedAddress = data.addressLines.join("\n");

Use structured data instead of formatted blocks

A display-ready block may hide information that should be queryable:

{
  "address": {
    "street": "123 Example Street",
    "unit": "Suite 400",
    "city": "New York",
    "region": "NY",
    "postalCode": "10001"
  }
}

Prefer this structure when consumers need to search, sort, translate, or validate the fields independently.

Long documents and source code

Escaped strings become hard to review when they contain long Markdown, HTML, SQL, certificates, or source code. Consider:

• Storing the content in a separate file and putting its path or URL in JSON.
• Using an array of lines when line-by-line processing is important.
• Using Base64 only for binary data or a transport that explicitly requires it; Base64 does not improve ordinary text readability.
• Choosing YAML for a human-authored configuration format that genuinely benefits from block scalar syntax.

If a system accepts JSONC or JSON5, it may add conveniences, but do not send those dialects to a strict JSON parser unless the contract explicitly allows them.

Double escaping

Escapes can be confusing when JSON is embedded inside a programming-language string:

const source = "{\"message\":\"First line\\nSecond line\"}";
const data = JSON.parse(source);

There are two layers here. JavaScript consumes \" and \\; then the JSON parser consumes \n. Whenever possible, build a JavaScript object and call JSON.stringify() instead of manually maintaining both layers.

JSON Lines is different

JSON Lines puts one complete JSON value on each physical line:

{"id":1,"message":"First line\nSecond line"}
{"id":2,"message":"Another record"}

It does not permit one JSON string to spill across physical lines. The line break inside the first message is still escaped.

Frequently asked questions

Can I use backticks in JSON?

No. Backticks create template literals in JavaScript, not strings in JSON. JSON strings must use double quotes.

Can I use triple quotes in JSON?

No. Triple-quoted strings belong to languages such as Python and some configuration formats. Serialize the resulting value to JSON and its line breaks will become \n escapes.

Does pretty-printing create multiline strings?

No. Pretty-printing adds whitespace between JSON tokens. It does not change the string value or put raw line breaks inside it.

Paste a failing payload into the JSON validator or use the JSON error analyzer to locate the invalid character.

Reference

• JSON string grammar in RFC 8259