.YML·File Extension

What is a .yml file?

A .yml file is a YAML Document — Alias extension for YAML documents.

In the mime-db registry it maps to text/yaml, and it is marked as compressible. When serving .yml over HTTP, set the Content-Type header as shown in Developer info below.

Related entities: it maps to text/yaml and is used by MiniYAML, OASv2-yaml among others — and is delivered over HTTP via the Content-Type header.

When served over HTTP, responses should set the following header:

Content-Type: text/yaml

Common software that reads/writes .yml:

• Configuration files
• Data interchange between systems
• API request and response payloads
• Logs and data exports

• Open the file with VS Code, make your changes and save.
• Most editors preserve the original formatting and encoding — avoid changing the charset.

• Create a new file and save it with the .yml extension, or export this format from VS Code.

• mime-db
• refnet data sources

Updated 2026-08-18