YAML to Properties (.env) Converter

Convert YAML to a Properties file online, for free, in your browser. This YAML to Properties converter flattens nested configuration from a .yaml or .yml file into dot-notated key=value pairs — the format used by Java .properties files and many .env-style configuration loaders.

Drop your YAML file here

Supports .yaml and .yml files, processed entirely on your device

Untitled.yaml0 B0 lines0 characters

YAML →JSON

Your converted output will appear here.

Waiting for YAML input.

What to expect

Nested keys are joined with dots, e.g. database.host=localhost.
List items use bracketed indices, e.g. servers[0]=alpha.
Values are written as plain text, so quote-sensitive values are left unescaped.

Example

Input (YAML)

site:
  name: Aperture Docs
  version: 1.4.2
  active: true
tags:
  - web
  - cli
  - tools
author:
  name: Jane Doe
  email: jane@example.com

Output (properties)

site.name=Aperture Docs
site.version=1.4.2
site.active=true
tags[0]=web
tags[1]=cli
tags[2]=tools
author.name=Jane Doe
author.email=jane@example.com

Why flatten YAML into a .properties file

Java and its ecosystem were built around java.util.Properties, and plenty of tooling still reads flat key=value files: Spring Boot's application.properties, Log4j and logging setups, build scripts, and internationalisation bundles. If your configuration lives in a nested YAML file but a component wants a flat file, this conversion produces it directly.

The same flat style is also close to what .env files and many container platforms expect. Dot-separated keys are easy to grep, easy to override one at a time, and easy to diff, which makes them popular for environment-specific overrides.

Spring Boot overrides
Create an application.properties file from an existing application.yml.
Legacy Java components
Feed libraries that only know how to load a Properties object.
Environment variables
Use the flattened keys as the basis for .env style settings.
Easy diffs and greps
Flat lines make it simple to search for, compare or override a single setting.

How YAML maps to Properties

These are the exact rules this converter applies. Each result below was generated by the tool itself, so it matches what you will see in the output panel.

Nested keys join with dots

The full path to every value is written on one line, joined by dots.

YAML

database:
  host: localhost
  port: 5432

Properties

database.host=localhost
database.port=5432

List items get bracketed indexes

Each element is written with its zero-based position, which Spring Boot reads back as a list.

YAML

servers:
  - alpha
  - beta

Properties

servers[0]=alpha
servers[1]=beta

Null values are left blank

A key with no value is written with nothing after the equals sign.

YAML

password: null
user: admin

Properties

password=
user=admin

Line breaks become \n

Multi-line text is kept on a single line so each property stays one line long.

YAML

message: |
  Hello
  World

Properties

message=Hello\nWorld\n

A trickier example: a Spring-style datasource

A typical application.yml fragment with a nested datasource, a list of pool names, a multi-line banner and an empty mapping.

Input (YAML)

spring:
  datasource:
    url: jdbc:postgresql://localhost/app
    pool: [primary, replica]
  banner: |
    Hello
    World
feature:
  flags: {}

Output (Properties)

spring.datasource.url=jdbc:postgresql://localhost/app
spring.datasource.pool[0]=primary
spring.datasource.pool[1]=replica
spring.banner=Hello\nWorld\n
feature.flags=

Each path is flattened to a single key, the list gains index suffixes, the banner's line break is escaped and the empty mapping is written as a blank value so the key is not lost.

Conversion notes for this example

Nested lists were flattened using bracketed indices, e.g. "key[0]".

Loading the properties in Java

The standard library reads the file straight into a Properties object. Note that bracketed keys such as pool[0] are ordinary key names to java.util.Properties:

java

Properties props = new Properties();
try (InputStream in = new FileInputStream("application.properties")) {
    props.load(in);
}

String url = props.getProperty("spring.datasource.url");
String first = props.getProperty("spring.datasource.pool[0]");

YAML vs Properties at a glance

Properties files are the flat cousin of YAML.

Feature	YAML	Properties
Structure	Nested	Flat keys with dots
Lists	Native sequences	Indexed keys (key[0])
Types	Numbers, booleans, null	Everything is a string
Comments	# comment	# or ! comment
Typical consumer	Kubernetes, CI, modern apps	Java, Spring, .env tooling

Things to watch for when converting to Properties

Every value becomes a plain string; the consuming application decides how to read numbers and booleans.
Values are not escaped for Java-specific rules (such as leading spaces or colons in keys), so check unusual strings.
Standard .env files use UPPER_SNAKE_CASE keys with underscores, so rename the dotted keys if your tool requires that.
YAML comments don't survive, and key order follows the order in the YAML.

YAML to Properties (.env) Converter FAQ

Can I use this output as a .env file?

Yes, though .env files conventionally use uppercase keys, so you may want to rename keys after exporting.

Can I convert YAML to Properties in Java?

Yes. In Java, load the YAML with SnakeYAML, flatten the resulting Map, and write each entry with java.util.Properties.store(). This tool gives you the same result instantly in the browser, without setting up a Java project.

How are nested mappings flattened?

Nested keys are joined together with dots, preserving the full path to each value.

Are comments preserved?

YAML comments aren't part of the parsed data, so they aren't carried over to the output.

Will Spring Boot read the indexed list keys?

Yes. Spring Boot's relaxed binding understands keys like servers[0] and servers[1] and rebuilds the list, which is the same syntax the converter writes.

How do I turn the result into a .env file?

Replace dots and brackets with underscores and uppercase the keys, for example DATABASE_HOST=localhost. The converter keeps dotted keys so you can choose the naming convention your platform uses.

What about special characters in values?

Values are written as plain text, with line breaks escaped. If a value has leading whitespace or characters your loader treats specially, review those lines by hand before using the file.

Is there a difference between .yml and .yaml?

No. ".yml" and ".yaml" are just two file extensions for the exact same format — this converter accepts either one, so a "yml to Properties" conversion and a "yaml to Properties" conversion produce identical results.

Related conversions

YAML to INI

Prefer sections over fully flattened keys? INI groups related settings under headers.

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YAML to TOML

Keep the nested structure but drop the indentation sensitivity.

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YAML to JSON

Need the structured version for a JavaScript or API consumer.

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Getting an error? Check your input with theYAML Validator, or tidy it first with theYAML Formatter. You can also browse all YAML converters.

YAML to Properties (.env) Converter

What to expect

Example

Why flatten YAML into a .properties file

Spring Boot overrides

Legacy Java components

Environment variables

Easy diffs and greps

How YAML maps to Properties

Nested keys join with dots

List items get bracketed indexes

Null values are left blank

Line breaks become \n

A trickier example: a Spring-style datasource

Loading the properties in Java

YAML vs Properties at a glance

Things to watch for when converting to Properties

YAML to Properties (.env) Converter FAQ

Related conversions

YAML to INI

YAML to TOML

YAML to JSON