Virtual tags

A virtual tag is a tag key LevelFour assigns to your cost from rules you write, alongside the tags your providers report. Use one to fix tags that disagree, to map accounts and services to owners, or to split a shared cost. Virtual tags in the guides explains how LevelFour picks a value and walks through the common patterns.

This page covers the editor in the dashboard. To keep tags in YAML files instead, see l4 tags.

Find your tags

Open Settings, then Tags. The page lists every tag key your organization has:

All tags, Virtual tags or Provider tags, from the tabs at the top
the key, its description, the providers it comes from, how many values and resources it has, and the spend it covers

The bar above the list compares Tagged spend with Untagged spend, across provider and virtual tags together.

Create a virtual tag

Start a new tag

Click Create new tag.

Name it

Under Tag key, type the name reports group by, such as team. It cannot repeat another virtual tag, and it cannot start with vtk_ or ptk_. Add a Description so the next person knows what it is for.

If the key matches one a provider already reports, the virtual tag extends that key. Can Override then decides who wins on a cost that carries both: turned on, your configurations decide the value; turned off, the provider's value stays wherever it exists.

Fold in provider keys, if they mean the same thing

Under Collapsed keys, add provider keys that are spellings of the same idea, such as env and Environment. They are read in order, before the configurations, and the first one present on a cost supplies its value.

Add configurations

Click Add configuration. Each configuration has three parts:

Assign decides what the matched cost becomes: One value, Split by percent across several values totalling 100%, or Split by cost, which divides it the way an existing tag key already does.
Match costs holds one or more rules. A rule names a provider and conditions such as account, region, service, tag or label. Cost matches when it matches any rule.
Time frame, optional, limits the configuration to cost billed between two dates.

Order sets priority: the first configuration that matches a cost wins. Drag a configuration to move it.

Preview, then save

Click Preview to see what the tag would claim over a recent window: spend and resources per value, plus what stays Unallocated and what is Shadowed by a configuration higher up. Adjust until the unallocated share is what you expect, then click Save tag.

To apply a tag to cost that is already billed, turn on Backfill past cost and pick the month to start from. LevelFour reprocesses those months in the background, and the tag's page shows progress until the figures update.

Edit a virtual tag

Open the tag from the list. Its page shows the values it assigns, its collapsed keys, its configurations in priority order, and the resources that carry it.

Edit tag changes the key name and description.
Each configuration can be edited, reordered or deleted. Cost a deleted configuration matched falls through to the next one once the tag is reprocessed.
A value can be renamed from the Values list.
Delete key removes the tag and its configurations, and reports lose it. This cannot be undone.

If someone else changes the same tag while you are editing, your save is refused and the page shows their version. Check it and make your change again. Neither edit silently overwrites the other.

Provider tags open read only. They are managed at the provider.

Where virtual tags show up

A saved virtual tag works where a provider tag does. Costs and Usage groups its breakdown by it under Virtual Tag, and cards such as Cost by Team on Boards can group by it. The API, the CLI and the MCP server read it too. The guide's Where virtual keys appear lists every place.

Who can change tags

Everyone in the organization can read tags. Creating, editing and deleting a virtual tag takes the Member or Admin role.

Virtual tags guide has the rule patterns: splitting a shared account, backfilling, nesting one tag in another
l4 tags keeps the same tags in files you apply from a terminal
Costs and Usage is where you read cost grouped by a tag