Why are some items wrapped in double quotes and others not?

YAML only requires quoting when a plain scalar would be ambiguous, for example an item that looks like a number, matches a reserved word like "true" or "null", starts with a YAML indicator character, or has leading/trailing whitespace. Everything else is left as a clean unquoted scalar.

Does this tool support nested lists or mappings?

No. It only produces a flat sequence of scalar values, one per input item. For nested YAML structures you'd need a general-purpose YAML authoring tool.

Which characters trigger quoting?

Leading/trailing whitespace, a leading YAML indicator character (-, ?, :, comma, brackets, braces, #, &, *, !, |, >, quotes, %, @, backtick), values that parse as numbers, YAML's reserved booleans/null words, and anything containing ": " or a newline.

Can I convert the YAML back into a plain list afterward?

Yes, use the companion YAML to List Converter, which parses a flat block sequence back into a plain list with your choice of separator.

List to YAML Converter - Turn a List into a YAML Sequence

Overview

Introduction

Config files, CI pipelines, and Kubernetes manifests all lean on YAML's block sequence syntax for lists, but hand-formatting a plain list of names, tags, or IDs into that syntax means remembering exactly when quoting is required.

This tool automates that step: paste a list with any separator and get back a ready-to-paste YAML sequence, with items quoted only where YAML's grammar actually demands it.

What Is List to YAML Converter?

The List to YAML Converter is a format converter that walks each item in your list and renders it as a `- item` line, YAML's standard block sequence notation.

It inspects each item against YAML's scalar-ambiguity rules and adds double quotes (with `\`, `"`, and newlines escaped) only when leaving it unquoted would change its meaning or break parsing.

How List to YAML Converter Works

The input is split into items using the separator you choose (newline, comma, or a custom delimiter), then each item is trimmed and blank items are dropped.

Each remaining item is checked against a set of YAML scalar rules, leading/trailing whitespace, reserved words, numeric-looking values, and indicator characters, and quoted only when one of those rules applies, then prefixed with "- " and joined with newlines.

When To Use List to YAML Converter

Use this when you need to drop a list of values, hostnames, feature flags, or tags into a YAML config file and want the quoting handled correctly instead of guessing.

It's also useful for quickly checking whether any of your list items would need quoting in YAML before you hand-edit a config file.

Often used alongside YAML to List Converter, List Base64 Encoder and List URL Encoder.

Features

Advantages

Only quotes items that genuinely need it, keeping the output as clean and readable as hand-written YAML.
Handles a configurable separator, so it works on newline lists, comma-separated values, or any custom delimiter.
Escapes backslashes, quotes, and newlines correctly inside quoted scalars.

Limitations

Only produces a flat sequence of scalars, no nested lists, mappings, or YAML anchors/aliases.
Does not attempt to preserve YAML comments or blank-line formatting since the input isn't YAML to begin with.

Examples

A simple list of names

Input

alice
bob
carol

Output

- alice
- bob
- carol

None of these items need quoting, so each becomes a plain unquoted YAML scalar.

A list with ambiguous items

Input

true
42
hello: world

Output

- "true"
- "42"
- "hello: world"

"true" and "42" would be parsed as a boolean and a number if left unquoted, and "hello: world" looks like a YAML mapping pair, so all three are quoted.

Best Practices & Notes

Best Practices

If your list items might contain colons, quotes, or look numeric, let this tool handle the quoting rather than guessing by hand.
Paste the output directly under a YAML key, for example `tags:`, followed by the generated block sequence indented to match your file.

Developer Notes

Quoting decisions are made with a small set of regular expressions checking for leading/trailing whitespace, YAML indicator characters, reserved boolean/null words, and numeric-looking strings; quoted scalars escape `\`, `"`, and `\n` via `String.prototype.replace()`.

List to YAML Converter Use Cases

Converting a list of environment names or feature flags into a YAML config array
Preparing a list of Kubernetes label values for a manifest
Turning a spreadsheet column export into a YAML sequence for a CI pipeline file

Common Mistakes

Assuming every item needs quotes; over-quoting a YAML file makes it harder to read and isn't necessary for plain words.
Forgetting that a YAML sequence needs consistent indentation once pasted into a larger document, this tool doesn't know your surrounding indentation level.

Tips

Use the comma separator if your source list is comma-separated, no need to reformat it to one-per-line first.
Run the output through a YAML linter if you're pasting it into a large, hand-maintained config file, just to be safe.

List to YAML Converter