List Converter — Remove Duplicates, Sort & Format Lists Online
Free online list converter. Remove duplicates from list, sort items, convert to comma separated, JSON arrays, or custom formats — all in your browser.
To convert a list, paste one item per line and set options such as separator, sort and remove duplicates; the formatted list appears below, ready to copy.
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List Converter — Remove Duplicates, Sort & Format Lists Online. Free online list converter. Remove duplicates from list, sort items, convert to comma separated, JSON arrays, or custom formats — all in your browser.
Instantly reformat multiple lines of text with our free remove duplicates from list and list formatting tool. This essential list converter lets you transform raw text lines into comma-separated values, JSON arrays, HTML lists, or any custom-delimited string.
Whether you're a developer preparing seed data, a marketer cleaning email lists, or an analyst deduplicating records, our list formatting tool delivers precise, instant results — paste your list and copy the output in seconds.
Our online list converter runs 100% in your browser — your data never leaves your device. Unlike cloud-based tools, this text list converter is completely private and works offline.
Sort ascending or descending, set custom separators, add prefixes and suffixes, convert to lowercase, and trim whitespace — all in one tool. Related tools: Base64 Encoder & Decoder, Text Diff Checker, Find and Replace.
Frequently asked questions
How do I convert a list to comma separated values?
Paste your items one per line into Your input data. With the default settings the output is a single line with the items joined by a comma and a space. Change Separator to any text, such as a semicolon, to use a different delimiter.
How do I remove duplicates from a list?
Keep Remove duplicates switched on, as it is by default. Repeated lines are removed and the first occurrence is kept. Items are trimmed first when Trim list items is on, so a line with extra spaces counts as a duplicate too. Turn on Convert to lowercase as well if Apple and apple should count as the same item.
How do I sort a list alphabetically?
Open the Sort list menu and choose Sort ascending or Sort descending. Leave it empty to keep your original order, or switch on Reverse list to flip the original order instead; the Sort list menu is disabled while Reverse list is on.
How do I turn a list into a JSON or SQL array?
Use Wrap item and Wrap list. For a JSON array, set the item prefix and suffix to a double quote and the list prefix and suffix to [ and ]. For an SQL IN clause, wrap items in single quotes and the list in parentheses.
What do Trim list items and Keep line breaks do?
Trim list items removes spaces at the start and end of each item; empty lines are always dropped. Keep line breaks puts each item on its own line after the separator instead of joining everything on one line.
Are my settings saved?
Yes. Your options are remembered in this browser for your next visit. Copy link creates a URL containing both your input and your options so someone else can reproduce the same conversion.
How to use this online tool
List Converter — Remove Duplicates, Sort & Format Lists Online is designed for fast browser workflows when you need to format, validate, convert, decode, encode, generate, or inspect data without opening a heavy desktop app. Start with the input field or visible options, review the result, then copy or download the output for the next step.
Private processing in your browser
List Converter — Remove Duplicates, Sort & Format Lists Online keeps the normal processing step local in your browser. That is useful for code snippets, tokens, documents, configuration values, text samples, and other material that should not be sent to a remote service unless you explicitly choose to share it.
When this tool is useful
Use List Converter — Remove Duplicates, Sort & Format Lists Online for repeatable developer tasks, technical documentation, QA checks, quick conversions, debugging, content cleanup, and internal team workflows. The page focuses on clear inputs, immediate feedback, and output that is easy to reuse in code, reports, tickets, emails, or notes.
Practical tips
Before copying the final result, check important details such as spacing, casing, filenames, encoding, token structure, line breaks, or output format. Small checks prevent mistakes when the result is reused in source code, API requests, documentation, spreadsheets, or shared files.