ASM Data & Text — A .asm file is a ASM Data & Text. It is a text-based data format widely used for configuration files, data interchange and API payloads.
Quick facts
What is .asm
A .asm file is a ASM Data & Text. It is a text-based data format widely used for configuration files, data interchange and API payloads.
In the mime-db registry it maps to text/x-asm. When serving .asm over HTTP, set the Content-Type header as shown in Developer info below.
Related entities: it maps to text/x-asm and is used by Assembly, Motorola 68K Assembly among others — and is delivered over HTTP via the Content-Type header.
How to open .asm files
Developer info
When served over HTTP, responses should set the following header:
Content-Type: text/x-asm
Common software that reads/writes .asm:
Relation chain
Related extensions
Related MIME types
Related programming languages
Common uses
How to edit .asm files
How to create .asm files
Frequently asked questions
Common options include VS Code, Notepad++, Sublime Text. 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 .asm extension.
text/x-asm is the media type identifier used for .asm files during network transfer (for example in the HTTP Content-Type header).
Sources & standards
Updated 2026-09-13
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