How to Add Offline License Activation to Your Software

Offline license activation lets your software confirm a valid license without any internet connection. Instead of calling a server, the app verifies a signed license file locally against a public key you embed at build time. Because the file is signed with a private key that never leaves your control, it cannot be forged or edited — making it perfect for air-gapped machines, secure facilities, and factory-floor deployments where network access is unavailable or forbidden.

How offline activation works

1. You issue a signed license file (a .lic file) for a customer from the dashboard.
2. You ship that file with — or alongside — your application.
3. On launch, your app verifies the file locally: it checks the signature, expiry, and any device or OS lock, all with no network call.

The security comes from the signature. The file carries the license details plus a cryptographic signature. Your app recomputes and verifies that signature with the embedded public key. Change one byte and verification fails.

Verifying an offline license in Python

from pylicensify import verify_offline_license

data = verify_offline_license("YOUR_PUBLIC_KEY", "license.lic")
print("Licensed to:", data.get("customer"))
print("Features:", data.get("features"))

If the signature, expiry, device binding, or OS lock does not check out, verification raises an error and you can refuse to start.

When to use offline vs. online validation

Use online validation when the machine has connectivity and you want live control — instant revocation, device tracking, and usage limits. Use offline files when the machine cannot reach the internet, or when you want the software to keep working with no dependency on a server. Many products support both: online by default, with an offline file as a fallback.

Frequently asked questions

Can an offline license be revoked?

Not remotely, by design — there is no callback. Control risk by issuing short expiries and re-issuing files, and by binding the file to a device or OS.

Is an offline license file safe to distribute?

Yes. It contains only license details and a signature, never your private key. It cannot be modified without breaking the signature, and it cannot be used to sign new licenses.

Can I lock an offline license to one machine?

Yes. Include a device (HWID) or OS lock when you issue the file, and verification will fail on any other machine.

Need air-gapped licensing? Create a free account and read the offline files documentation.