Staaarter Tools

YAML to NestedText Converter

Paste YAML and get back NestedText (nestedtext.org): `key:` for mapping entries, `- ` for list items, and `> ` lines for multiline strings, a format designed to have no type conversions to get wrong because every value is just text. A free online tool from Staaarter, right in your browser.

Runs locallyUpdated 2026-07-22
conversionconfiguration

Overview

Introduction

NestedText trades YAML's rich type system for a much simpler guarantee: whatever you write is exactly what you get back, because everything is a string. That tradeoff is appealing for configuration that's read by humans and hand-edited often, where YAML's implicit typing (unquoted `no` becoming boolean `false`, a version string becoming a float) has caused real bugs.

This tool converts YAML into that format, useful when you're evaluating NestedText for a project or need to hand off structured data to a tool that reads it.

What Is YAML to NestedText Converter?

A YAML-to-NestedText converter walks a parsed YAML document and renders it using NestedText's three constructs: `key:` lines (optionally followed by an indented nested block) for mapping entries, `- ` lines for list items, and `> `-prefixed lines for any string that spans multiple lines.

Because NestedText has no separate type system, every YAML scalar, whether it was a quoted string, a bare number, or a boolean, is converted to its plain text representation.

How YAML to NestedText Converter Works

The YAML input is parsed with the same parser used across this category. The resulting value is walked recursively: nested non-empty mappings and sequences open an indented block under their key or dash, while scalar leaves are written inline after `key: ` or `- ` unless they contain a newline, in which case they're broken into `> `-prefixed lines instead.

Numbers and booleans are converted with `String()`; null becomes an empty value, since NestedText has no way to distinguish 'empty string' from 'absent value' beyond that.

When To Use YAML to NestedText Converter

Use it when migrating configuration to a tool or library that reads NestedText, or when evaluating whether NestedText's simpler type model would prevent a class of bugs your YAML config has hit before.

It's also useful for producing a human-diffable, type-ambiguity-free snapshot of a YAML document for documentation or review.

Often used alongside NestedText to YAML Converter, YAML to JSON Converter and YAML Formatter & Prettifier.

Features

Advantages

  • Removes YAML's implicit-typing surprises entirely, since everything becomes text on the way out.
  • Multiline strings are represented unambiguously with explicit `> ` markers, unlike YAML's several competing multiline styles.
  • Produces a format that's easy to read and diff, one value per line, minimal punctuation.
  • Runs entirely client-side, so configuration values never leave your browser.

Limitations

  • Type information is inherently lost: a YAML boolean `false`, the number `0`, and the string `"false"` no longer look different once serialized to NestedText's all-text format, only the exact converted text survives.
  • Empty YAML mappings and sequences don't have a distinct NestedText representation; they come through indistinguishable from an entry with an empty string value.
  • Keys containing a literal colon followed by a space, or other characters NestedText treats as syntactically significant, aren't escaped by this converter and may need manual adjustment.

Examples

A flat mapping

Input

name: api
replicas: 3

Output

name: api
replicas: 3

Scalar values are written inline after the key, exactly like YAML's own flow, just without type-specific formatting.

A multiline string

Input

note: "line1\nline2"

Output

note:
  > line1
  > line2

Each line of the string gets its own `> `-prefixed line, indented under the key.

Best Practices & Notes

Best Practices

  • If round-tripping matters, keep the original YAML as the source of truth, since converting back loses the distinction between a string "3" and a number 3.
  • Review keys for embedded colons or leading dashes before converting, NestedText's parser treats those characters specially at the start of a line.
  • Use this conversion as a way to audit which YAML values are 'accidentally typed' by seeing them all flattened to plain text.

Developer Notes

The serializer is hand-written (no NestedText library dependency), recursively walking the parsed YAML value and choosing between inline (`key: value`), block (`key:` plus an indented nested structure), and multiline (`> ` lines) rendering based on the value's shape. Two-space indentation is used per nesting level, consistent with this site's other structured-text tools.

YAML to NestedText Converter Use Cases

  • Migrating human-edited configuration to a tool that reads NestedText
  • Auditing a YAML config for implicit type conversions by seeing every value reduced to plain text
  • Producing a simple, diff-friendly snapshot of structured data for documentation
  • Evaluating NestedText as a lower-risk alternative to YAML for hand-edited config files

Common Mistakes

  • Expecting the NestedText output to preserve whether a value was originally a number, string, or boolean, it doesn't, by design.
  • Forgetting that an empty YAML mapping or list and a key with an empty string value look identical in the NestedText output.
  • Assuming YAML comments carry over, they don't; NestedText comments (lines starting with `#`) are a separate feature this converter doesn't generate.

Tips

  • If you need type information preserved, convert to JSON or keep the original YAML instead of NestedText.
  • Use Extract Strings from YAML first if you specifically want to review the string values that will end up unquoted in the output.
  • Pair with NestedText to YAML afterward to confirm a specific document round-trips the way you expect.

References

Frequently Asked Questions