Marko Apfel
Development

That Mysterious '>>' Prefix in .resx Files, Explained

What the '>>' prefix convention in .resx resource keys typically signals, and why it isn't part of the .NET resource file specification.

2 min read

If you’ve spent time in a .resx file, you may have run into a resource key prefixed with >> — appearing in the raw XML as >>, the escaped form of >>. It’s easy to assume this is some documented part of the .NET resource file format. It isn’t. It’s a convention, and one worth understanding before you either adopt it or trip over someone else’s use of it.

It’s not part of the .NET spec

There’s nothing in the .resx schema or the .NET resource pipeline that assigns special meaning to a >> prefix. Any behavior tied to it comes entirely from team or tooling conventions layered on top of the format.

What teams typically use it for

Marking special or metadata entries. A >> prefix often flags an entry as something other than ordinary translatable content — for example, metadata about the resource file itself, or a key meant to guide processing tooling without being intended for translation:

<data name=">>Metadata" xml:space="preserve">
  <value>Do not translate</value>
</data>

Differentiating keys at a glance. In files mixing user-facing strings with internal configuration or placeholder values, the prefix acts as a quick visual signal that a key isn’t meant to reach the UI.

Tool-specific reservations. Some localization tools reserve prefixes like this for their own bookkeeping — auto-generated entries, or additional context passed to a localization team.

Team-specific conventions. Just as often, it’s simply something a team invented to make resource keys easier to manage — flagging entries that need review, are placeholders, or belong to a particular logical group.

Seeing it in context

<data name=">>NonLocalizable.HelpText" xml:space="preserve">
  <value>This is an internal note for developers.</value>
</data>
<data name="AppTitle" xml:space="preserve">
  <value>My Application</value>
</data>

Here, >>NonLocalizable.HelpText reads as a note for developers rather than translatable content, while AppTitle is clearly meant to be localized.

The takeaway

If you encounter this prefix in a codebase, don’t assume it’s a .NET behavior you’re missing — go find the team or tooling convention behind it. And if you’re introducing it yourself, document it explicitly. A convention that only lives in one person’s head stops being useful the moment that person moves to a different project.