Source Map File — JSON source map linking minified code to sources.
Quick facts
What is .map
A .map file is a Source Map File — JSON source map linking minified code to sources.
In the mime-db registry it maps to application/json with UTF-8 encoding, and it is marked as compressible. When serving .map over HTTP, set the Content-Type header as shown in Developer info below.
Related entities: it maps to application/json — and is delivered over HTTP via the Content-Type header.
How to open .map files
Developer info
When served over HTTP, responses should set the following header:
Content-Type: application/json; charset=utf-8
Common software that reads/writes .map:
Relation chain
Related extensions
Related MIME types
Common uses
How to edit .map files
How to create .map files
Frequently asked questions
Common options include Chrome DevTools, VS Code. You can also open many of these files with built-in viewers or a browser.
Create a new file in any text editor or the app that owns the format and save it with the .map extension.
application/json is the media type identifier used for .map files during network transfer (for example in the HTTP Content-Type header).
Sources & standards
Updated 2026-08-18
Explore this reference