When creating a product or product variant in Lemon Squeezy you will have the option to Generate License Keys. License keys are normally used to restrict access to some external bit of content, such as a software application.
You can use license keys to require proof that the customer has paid for access to the content. For more information on how to integrate with Lemon Squeezy to restrict access to content see our Licenses API doc.
When the Generate License Keys setting is enabled, a unique license key will be generated for each customer that purchases the product. The customer will be able to see their license key in their order receipt email and when viewing their order on the My Orders page.
License Length & Activation Limit
You can control how long a license key will be considered "valid" and how many times it can be activated using the License length and Activation limit settings.
As an example, say you sell a software product where you offer 1 year of support for the product. You could set the license length to "1 Year" and restrict access to your support helpdesk to customers with a valid license key. After their license expires, the customer would need to purchase a new license to get continued access to your support helpdesk.
Then, let's imagine your product costs $9 and the activation limit is set to "1" so that the customer can only use your software product on one computer. If they try to activate the same license on more than one computer it won't work as the license will have reached its activation limit.
In this case, you might want to create a new variant for your product with a higher price that allows more activations. For example, you could create a new variant for $19 that has an activation limit of "3". With this license, the software can be used on up to 3 computers before the license key can no longer be activated.
If you use the Redirect after purchase setting to redirect your customers to a specific URL after a successful purchase, you can use the [license_key] variable in the URL.
This placeholder will be replaced with the real license key when a customer purchases your product.
That way, when they get redirected to your URL you can do some processing with their license key. This can be used to improve the onboarding experience for new customers by removing the need for them to enter their license key manually.