Using license keys for your products

In this article:

If you sell software, plugins, themes, game assets, or anything else that needs a serial number, Sellfy can now handle license keys for you. Enable license keys for a product, and every buyer automatically receives their own unique key with their purchase - no spreadsheets, no manual emails.

Enabling keys

When creating or editing a digital product, go to the Advanced settings tab. There you can enable license keys for that product.

You'll pick one of two modes:

Generated keys - Sellfy creates a unique key for every sale automatically (in the familiar XXXX-XXXX-XXXX-XXXX format). You never run out, and there's nothing to maintain.
Your own keys - paste in a list of keys you already have (for example, keys exported from another platform or issued by your own system). Sellfy hands them out one by one and automatically stops sales when the list runs out, so you never oversell.

How it works

When a customer completes a purchase, their key is issued instantly and shown right on the order confirmation and download page. If they buy several copies, they get a key for each one.

Keys for subscription products stay tied to the subscription - if the subscription lapses, the key expires with it.

Managing existing keys

Every key is shown in your dashboard, where you can easily track its status and take action if needed:

Track activity - See when a key was issued, whether it's active, and view its full history.
Revoke access - Instantly disable a leaked or misused key with one click.
Reactivate - Restore a previously revoked key if it was a mistake.

Connect it to your software by API

The real power comes from the Sellfy API. Your app can check a key the moment a customer types it in:

Validate - is this key genuine and still valid?
Activate - register an installation (you can attach details like a device ID or IP address), and count activations to enforce your own limits, like "3 devices per license."
Deactivate - free up a seat when the customer moves to a new machine.
Revoke - kill a key programmatically.

Full endpoint reference, request examples, and authentication details are in the Sellfy API documentation.

Webhooks

Prefer to be notified instead of asking? Sellfy can ping your server whenever something happens to a key:

Webhook	Fires when
`license_key.issued`	A new key is delivered to a buyer
`license_key.activated`	A buyer activates their key in your app
`license_key.revoked`	You revoke a key
`license_key.expired`	A key expires (e.g. its subscription lapsed)

Every webhook passes data, so your system stays in sync with your sales. Each one includes:

the key
the product it belongs to
the customer's email

Technical details

Sellfy-provided keys are generated by a cryptographically secure random generator and are guaranteed unique per product. The character set deliberately skips look-alike characters (no 0 /O or 1 /I ), so keys are easy to read over the phone or retype from a screenshot.

Keys move through a simple lifecycle - issued → activated, with revoked and expired as the exit states and every change is recorded in an activity log you can inspect per key.

All API requests are authenticated with your personal API token and only ever see your own keys.

More on integration is available in our API docs.