pylicensify 1.0.0

Client SDK for PyLicense — verify software license keys with tamper-proof, signed responses.

pylicensify

Client SDK for PyLicense — verify software license keys with tamper-proof, signed responses. A cracked "fake server" can't grant access, because every response is verified against your public key.

pip install pylicensify

Quick start

Get your public key from the dashboard → Integration page (safe to embed in your distributed app; the private key never leaves the server).

from pylicensify import LicenseClient

client = LicenseClient(public_key="YOUR_PUBLIC_KEY")

result = client.validate("PY-XXXXXXXXXXXXXXXX")
if result:
    print("Licensed. Entitlements:", result.features)
    if result.feature("pro"):
        enable_pro_features()
else:
    print("Not licensed:", result.error)
    raise SystemExit(1)

validate() sends a nonce, verifies the Ed25519 signature, and rejects stale / replayed responses automatically. It raises SignatureError on tampering and NetworkError if the server is unreachable.

Feature gating

result = client.validate(key)
seats = result.feature("seats", 1)
if result.feature("pro"):
    ...

Offline license files (air-gapped)

Issue a signed .lic file from a license row in the dashboard, ship it with the app, and verify it locally with zero network calls:

from pylicensify import verify_offline_license

data = verify_offline_license("YOUR_PUBLIC_KEY", "license.lic")
print("Valid for:", data.get("customer"), data.get("features"))

Checks signature, expiry, device binding, and OS lock.

Floating / concurrent licenses

For keys with a concurrent-session limit — the SDK checks out a seat, heartbeats in the background, and releases on exit:

from pylicensify import LicenseClient, SeatUnavailable

client = LicenseClient(public_key="YOUR_PUBLIC_KEY")
try:
    with client.session("PY-XXXX...") as sess:
        print("Seat acquired:", sess.seats)   # {'used': 1, 'max': 5}
        run_app()                              # released automatically on exit
except SeatUnavailable:
    print("All seats are in use — try again later.")

Update checks

info = client.check_update("PY-XXXX...", current_version="1.0.0")
if info["update_available"]:
    print("New version:", info["version"], info["notes"])
    # info["download_url"] is a license-gated download link

Self-hosted / custom domain

client = LicenseClient(public_key="...", api_url="https://license.yourdomain.com")

Hardware ID

By default the SDK derives a machine id from uuid.getnode(). Pass your own for a stronger fingerprint:

client.validate(key, hwid=my_custom_fingerprint())

Errors

Exception	Meaning
InvalidLicense	Server rejected the key (invalid/expired/revoked/blocked)
SignatureError	Signature/nonce/timestamp failed — forged or replayed
NetworkError	Couldn't reach the license server
SeatUnavailable	Floating license has no free seats

All inherit from LicenseError.

Hardening

Obfuscate your client so the check itself can't be trivially patched out — e.g. with PyObfuscate.