What does each line become in the output?

Each non-skipped line becomes one element of the array, in the same order. Paste three lines apple, banana, cherry and you get ["apple","banana","cherry"]. Blank lines are dropped by default so you never end up with empty-string elements, and the order is preserved unless you turn the sort option on, which reorders alphabetically with numeric-aware collation so 10 sorts after 2.

Should numbers be converted to a JSON number automatically?

That is what the type inference toggle decides. With it on, a line that is exactly a number, true, false or null becomes that JSON primitive, so 42 is the number 42 and true is the boolean true. With it off, every element stays a string, so you get ["42","true"]. Inference is strict: 1abc, 0x10 and a phone number with a leading plus and dashes stay strings, so it will not silently mangle IDs or codes that merely start with digits.

How do I remove duplicate lines?

Turn on Remove duplicates. The tool keeps the first occurrence of each line and drops every later repeat, comparing the lines after trimming if trim is on. So the four lines a, b, a, c collapse to ["a","b","c"]. Pair it with Sort if you also want the result ordered. Dedupe runs before type inference, so it matches on the text you see, not on the inferred value.

How do I split a JSON array back into lines?

Switch the direction to JSON array to list and paste your array, for example ["red","green",3,true]. You get one element per line: red, green, 3, true. String elements print without their surrounding quotes so you get plain text back, while numbers, booleans, null and nested objects print as their JSON text. If the JSON is broken, like a missing closing bracket, you get a readable error instead of a blank box.

Will my quotes and special characters be escaped?

Yes. The output is built with real JSON serialization, so a line containing a double quote, a backslash or a tab is escaped to a valid JSON string and round-trips back to the original text exactly. You do not add quotes yourself; the tool wraps each string element for you. This is the main reason to use the tool instead of hand-typing brackets and commas, where one stray quote breaks the whole array.

Is anything sent to a server?

No. The split, the type inference, the dedupe, the sort and the JSON serialization are plain JavaScript that runs in your browser tab. Your list never leaves the page and nothing is logged. The one thing to know: the shareable URL encodes your input in the query string, so a share link pasted into chat records that text in the recipient server log. For sensitive lists use the copy button instead of sharing the URL.

Seed a config or fixture from a pasted column

You copy a column of country codes or SKU ids and need a JSON array for a config file. Paste it, leave type inference off so codes stay strings, then copy the array straight in. No hand-typed brackets, no missing comma on line 40 breaking the parse.

Read a one-line JSON array a teammate sent

A colleague pastes a long single-line JSON array and asks what is in it. Switch to the reverse direction, paste it, and read one element per line. Strings show without quote noise, and a malformed array surfaces the parse error instead of a blank box.

List to JSON Array Converter

Turn a column of lines into a JSON array, with type inference, dedupe and pretty print, and split it back to lines, all in your browser

Runs locally
Category Format Converter
Best for Turning pasted content or local files into a handoff-friendly format.

Direction

Input

Output (0 items)

[]

What this tool does

Free list to JSON array converter. Paste one item per line and get a clean JSON array of scalars back, ready to drop into a config file, a test fixture, an API request body or a SQL seed script. Type inference turns lines that look like numbers, true, false or null into real JSON primitives, so 42 becomes the number 42 instead of the string "42"; turn it off when you want every element kept as a string. One pass also handles the housekeeping most people do by hand: trim each line, skip blank lines, remove duplicates and sort. Choose compact output for one tight line or pretty print at two or four spaces for a readable diff. Quotes, backslashes, tabs and Unicode are escaped correctly because the output goes through real JSON serialization, not string glue. Need the inverse? Switch direction and paste a JSON array to fan it out to one element per line, with a friendly error if the JSON is malformed. Everything runs in your browser tab with one-click copy and a shareable URL that reproduces your exact input and options. 100% client-side, nothing uploaded.

Tool details

Input: Text + Numbers + Structured content; The page exposes text boxes, numeric controls, file pickers, or structured inputs depending on the tool.
Output: Live result + Copy; The result area focuses on usable output, with copy, download, or preview actions when supported.
Privacy: Browser-side processing; The main tool logic does not call an external API, so inputs normally stay in the current tab.
Save / share: Shareable URL state; Key settings are encoded in the URL so another person can reopen the same setup.
Performance budget: Initial JS <= 9 KB; No WASM budget is declared, keeping the tool quick to open on mobile.
Best fit: Format Converter · Developer; Category and role tags drive related tools, internal links, and quick fit checks.

How to use

1. Input

Paste or drop your content into the tool panel.
2. Process

Click the button. All processing is local in your browser.
3. Copy / Download

Copy the result or download to disk in one click.

How List to JSON Array fits into your work

Use it when the main problem is getting content from one practical format into another.

Conversion jobs

Turning pasted content or local files into a handoff-friendly format.
Previewing a conversion before you use it in a larger workflow.
Cleaning small format mismatches without opening a full editor.

Conversion checks

Try a small sample first when the source format is messy.
Check character encoding, separators, and line endings after conversion.
Keep the source until the converted output has been reviewed.

Good next steps

These links move the current task into a more complete workflow.

Real-world use cases

Seed a config or fixture from a pasted column
You copy a column of country codes or SKU ids and need a JSON array for a config file. Paste it, leave type inference off so codes stay strings, then copy the array straight in. No hand-typed brackets, no missing comma on line 40 breaking the parse.
Read a one-line JSON array a teammate sent
A colleague pastes a long single-line JSON array and asks what is in it. Switch to the reverse direction, paste it, and read one element per line. Strings show without quote noise, and a malformed array surfaces the parse error instead of a blank box.

Common pitfalls

Expecting numbers with type inference off. Off means every element stays a string, so you get ["1","2"] not [1,2]. Flip the toggle on first.
Assuming inference parses anything numeric-looking. It is strict: 0x10, version 1.2.3 and id 007-A stay strings. Only clean numbers, true, false and null convert.
Pasting a JSON object into the reverse direction. It accepts only a top-level array; {"a":1} returns a not-an-array error, so wrap your values in brackets first.

Privacy

The line split, type inference, dedupe, sort and JSON serialization all run as plain JavaScript in your browser tab. Your list never leaves the page and nothing is logged. Note the shareable URL puts your input in the query string, so for confidential ids or keys use the copy button instead of sharing the link.

FAQ

Tool combos

Folks in your role tend to reach for these alongside this tool.

Developer

Browse all tools for this role

List to JSON Array Converter

What this tool does

Tool details

How to use

1. Input

2. Process

3. Copy / Download

How List to JSON Array fits into your work

Conversion jobs

Conversion checks

Good next steps

Real-world use cases

Seed a config or fixture from a pasted column

Read a one-line JSON array a teammate sent

Common pitfalls

Privacy

FAQ

JSON Lines Formatter

Properties ⇄ JSON Converter

List to Comma Separated

CSV ⇄ JSON Converter

JSON Formatter & Validator

Text Sorter

Angle Converter

Base64 Encoder & Decoder

Base64 to File Converter

BBCode to HTML Converter

Chinese Numeric Converter

Chinese Pinyin Converter