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json-to-single-line-string

Converting JSON to a single-line string collapses whitespace and (optionally) escapes quotes so the result fits in a JavaScript string literal, an environment variable, a YAML scalar, a curl --data argument, or a single CSV cell. The ZTools JSON to Single Line String tool offers two modes: minified JSON (whitespace removed but quotes intact), and JSON-string-of-JSON (the whole thing wrapped in quotes with backslash escaping, suitable for embedding inside another JSON document or a JS string literal).

Use cases​

Embed JSON in a .env file​

Twelve-factor apps put config in env vars. A multi-line JSON config has to collapse to one line — and quotes typically need escaping for the shell.

Build a curl command​

curl -d expects a single-line argument. Pretty-printed JSON breaks the command. Collapse first, then paste.

Inline JSON in a YAML scalar​

YAML allows multi-line scalars but inline single-line is simpler. "config: '{...}'" — the inner JSON must be one line.

Paste into a SQL TEXT column​

Storing JSON in a TEXT/VARCHAR column — single-line is friendlier to SQL clients that show one row per line.

How it works​

  1. Paste pretty-printed JSON — Whitespace and indentation get stripped. The tool first JSON.parse to validate, then JSON.stringify with no spaces to re-emit.
  2. Pick mode — Minified (output is valid JSON) or escaped string (output is a JS / JSON string literal of the JSON).
  3. Choose quote style — Wrap in single quotes (shell-friendly), double quotes (JS-friendly), or no quotes (plain minified JSON).
  4. Copy result — One-click copy. The output is the full string, ready to paste into env / curl / code.

Examples​

Input: { "name": "Alice", "tags": ["a", "b"] }

Output: Minified: {"name":"Alice","tags":["a","b"]}.

Input: Same input, escaped mode

Output: "{\"name\":\"Alice\",\"tags\":[\"a\",\"b\"]}" — fits inside a JS string literal or a JSON string field.

Input: For curl: --data "{...}"

Output: curl -X POST -d '{"name":"Alice","tags":["a","b"]}' https://api.example.com — single quotes survive the shell unescaped.

Frequently asked questions​

How is this different from JSON minifier?

A minifier removes whitespace. This tool also offers the "escape as string" mode — wrapping the result so it can be embedded inside another JSON or JS string. Minify alone isn't enough for nested embedding.

Does it preserve key order?

JSON.stringify follows the order of insertion in the parsed object — usually preserved by modern JS engines but not guaranteed by the JSON spec. If order matters, document your assumption.

What about Unicode characters?

Native UTF-8 in the output by default. Toggle "escape non-ASCII" if your downstream system mangles non-ASCII bytes (rare but happens with old logging pipelines).

Can it handle 10 MB JSON?

Yes — JavaScript handles large strings fine. Pasting 10 MB into a browser textarea is the slow part; uploading a file is quicker.

Is the output still valid JSON?

Minify mode: yes. Escape mode: the output is itself a string — pass it through JSON.parse once to recover the original JSON.

Does it strip comments?

Strict JSON has no comments, so input with comments fails to parse. Run a JSON5-aware preprocessor first if needed.

Tips​

  • For env vars, prefer base64-encoding very large JSON — line-noise but no escaping issues.
  • When embedding in a shell command, single quotes (') beat double quotes (") because nothing inside single quotes is interpreted by the shell.
  • For Postman / curl test scripts, paste the raw JSON object — most clients minify under the hood. Manual minification is only needed for env vars and command-line args.

Try it now​

The full json-to-single-line-string runs in your browser at https://ztools.zaions.com/json-to-single-line-string — no signup, no upload, no data leaves your device.

Open the tool ↗

Last updated: 2026-05-06 · Author: Ahsan Mahmood · Edit this page on GitHub