Privacy & Security Note: To prevent email enumeration attacks, our server always returns the same generic confirmation message. If an active, eligible subscription is associated with your email in Stripe, your license key will be delivered within two minutes.

How Cryptographic License Keys Work

Deleix Invoice Maker uses a stateless cryptographic licensing model that eliminates the need for centralized user accounts, password hashes, and vulnerable customer profile databases. When you subscribe, your unique Stripe customer identifier is cryptographically signed using HMAC-SHA256 with our secure server key. This produces a string formatted as DIM1.customer_id.signature.

Because the key itself contains both your customer reference and its authenticating cryptographic signature, our API can instantly verify whether your subscription is valid without storing any personal records or passwords on our servers. Once verified, your browser caches the validation status and only re-checks with our API once every 24 hours.

Best Practices for Managing Your License Key

Because Deleix Invoice Maker does not maintain server-side login profiles or password credentials, treat your license key like a software activation code:

Store in Your Password Manager: Save your license key in your preferred credential manager (such as 1Password, Bitwarden, KeePass, or Apple Keychain) under a secure software license note.
Multi-Device Flexibility: You may activate your single Pro subscription across multiple personal devices—such as your desktop workstation, travel laptop, and tablet—without per-seat license penalties. Simply enter your key into the activation box on each device.
Key Revocation & Security: If you accidentally publish or expose your license key publicly, contact our support team immediately. We can re-issue a fresh cryptographic signature linked to your Stripe customer record and deactivate the exposed string.

Troubleshooting License Recovery

I didn't receive the recovery email. What should I check?

First, check your spam or junk mail folders. Because our emails are pure plain text without marketing graphics or tracking pixels, they typically arrive immediately, but corporate spam filters may occasionally filter automated messages. Second, verify that you entered the exact email address used during your original Stripe checkout (for example, a personal PayPal/Apple Pay email rather than your business domain).

What if my subscription was purchased under an old email address?

If you no longer have access to the email address you originally used at checkout, please contact our support team at [email protected] with your approximate subscription date and the last 4 digits of the payment card used. We can verify your account in Stripe and update your email address securely.

Does restoring my key charge my card again?

No. Restoring an existing license key is completely free. Your key represents your existing active subscription; you will never be charged an additional fee for moving your key to a new browser, restoring access on a replacement computer, or recovering a misplaced key.

What happens during a temporary network outage?

If you are traveling, working offline, or our verification servers experience a temporary interruption, Deleix Invoice Maker Pro provides an automated 7-day offline grace period. Your editor will continue providing full Pro functionality without interruption for up to 7 full days, and your stored license key will never be deleted.