Two kinds, counted separately.
One is consumed when a person signs in on a device with the Client Agent. Revoking a device releases what it held.
A gateway is activated with a server licence key generated on this page. Create a key, then paste it during installation or into the agent's configuration.
Each key records the machine it activated on and when it was last validated, so you can tell an unused key from a live one.
When licences are exhausted, new sign-ins are refused while existing sessions continue. Revoke assets you no longer use, or raise your plan on the Plan page.
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