Flag types

Vexil supports five flag types — from simple on/off switches to fully typed configuration values.

Type	Returns	Best for
Boolean	true / false	Feature on/off, kill switches
String	A text value	Variant names, UI copy, config strings
Number	A number	Timeouts, thresholds, rate limits
JSON	An object or array	Structured config, multiple settings at once
Gradual	true for N% of users	Percentage-based rollouts

The flag type cannot be changed after creation. If you pick the wrong type, archive the flag and create a new one.

Creating a flag

1
Click "New flag" in the Flags page
The creation modal opens.
2
Choose a type
When in doubt, start with Boolean.
3
Enter a flag key
The key is what your code uses to evaluate the flag — e.g. dark-mode or new-pricing-page. It must be unique within your org and URL-safe.
4
Set default values per environment
These are the fallback values the SDK returns if it can't reach the server.
5
Click "Create flag"
Your flag is live, starting disabled in all environments.

Archiving a flag

Once a feature is fully shipped and stable, archive its flag to keep the dashboard clean. Archived flags are hidden by default but remain in the audit log. You can restore them at any time from the archived flags view.

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