YAML ↔ Properties Converter
Local processing · never uploadedConvert YAML to Properties and back — Spring Boot friendly, loss-aware, 100% client-side.
What is YAML ↔ Properties Converter?
YAML ↔ Properties Converter is a fast, free online tool that converts between YAML and Java Properties in both directions, instantly and entirely inside your browser. Paste an application.yml to turn it into application.properties, or paste a .properties file to rebuild the nested YAML — ideal for Spring Boot configuration, Kubernetes manifests and any Java config migration.
YAML and Properties are two of the most common formats for Java configuration, and switching between them is a daily task for backend developers. Spring Boot accepts both application.properties and application.yml, so teams frequently convert one to the other to match a convention, to compare configs, or to migrate a project. Doing this by hand is slow and brittle, because the two formats do not carry the same information: YAML supports nesting, arrays and typed values, while Properties is a flat list of key=value strings. This converter handles the mapping for you and, uniquely, tells you exactly what was lost or changed in the process.
Converting YAML to Properties is always lossless: nested maps flatten into dot-path keys (server.port=8080), and arrays expand into indexed entries (list[0], list[1]) so they can be reversed later. Converting Properties back to YAML is also reliable, but Properties cannot encode arrays or value types on its own, so the converter is explicit about it. By default every value stays a quoted string, and you can opt in to type inference so that 8080 becomes a number and true becomes a boolean, or split comma-containing values into arrays. The status line always reports what happened — arrays flattened, types converted, values kept as strings — so the result is transparent rather than a silent guess.
Everything runs locally in your browser, so sensitive configuration such as database passwords, API keys and credentials is never uploaded, logged or stored. The same conversion is also available as a REST endpoint, so you can wire it into scripts and pipelines when you need to automate the transform at scale.
FAQ
Can it convert both YAML to Properties and Properties to YAML?
Yes. The tool detects the direction automatically from what you paste, and you can lock or swap it manually with one click. YAML→Properties is always lossless; Properties→YAML is reliable but, because Properties has no arrays or types, the status line tells you exactly how values were interpreted.
How are arrays handled?
When converting YAML to Properties, arrays expand into indexed keys like list[0]=a, list[1]=b, which can be reversed back into a YAML array. You can alternatively join them with commas, but that is lossy and cannot be reversed. The status line notes which strategy was used.
Why are my numbers and booleans quoted in the YAML output?
Properties stores everything as strings, so the converter keeps values as strings by default to avoid guessing. Enable type inference to have 8080 interpreted as a number and true as a boolean. The choice is always visible in the status line.
Is my configuration uploaded anywhere?
No. The conversion happens entirely in your browser. Your YAML and Properties — including any passwords or secrets — are never sent to a server, so it is safe to convert real production configs.
Does it support the full YAML spec?
It supports the subset that configuration files actually use: indented maps, block sequences (- item), flow collections ([a, b]), typed scalars and comments. Advanced features like anchors, aliases and multi-document files are not supported, and the tool tells you so rather than failing silently.