SunLicenseSelling a Python tool? Give every buyer a key.
One SDK call. Keys from your store, machine limits, refunds off.
Free plan · No credit card · Set up in minutes
Coding with an AI agent? Paste one prompt- Python
- Gumroad
- Lemon Squeezy
- Ko-fi
- Payhip
- Stripe
- Windows
- macOS
- Linux
Built for how you sell.
pip install sunlicense
Standard library only, Python 3.8+.
result.validMachine limits
1, 2 or 5 machines per license.
TOO_MANY_MACHINESKeys from your store
Gumroad, Lemon Squeezy, Payhip, Ko-fi or Stripe.
Subscriptions and trials
Ended subscriptions suspend the key.
Offline license files
Signed, checked with your public key.
Ed25519Key inside the zip
Portal downloads carry each buyer's key.
StandardLive before your next release.
- 1Create a free account
- 2Connect your store
- 3pip install, check on start
import platform
import sys
from sunlicense import SunLicense # pip install sunlicense
client = SunLicense(base_url="https://api.sunlicense.com",
token="slk_...") # API key: validation only, safe to ship
def require_license(key: str) -> None:
result = client.validate(key, host=platform.node())
if not result.valid: # result.data["code"] says why, e.g. TOO_MANY_MACHINES
sys.exit("License not valid. Manage your key at yourtool.example/account")Questions, answered.
How do I add a license key to a Python script?
Run pip install sunlicense, create an API key in the dashboard, and call client.validate(key, host=machine_id) when your tool starts. It returns valid, the HTTP status and the JSON answer with a code such as EXPIRED or TOO_MANY_MACHINES. The SDK uses only the standard library, so there are no extra dependencies to bundle.
Can't buyers just delete the check from a .py file?
Someone determined can: Python source can be edited, and packaging with PyInstaller only makes that harder. A key check stops casual sharing and refunded copies. Anything your tool does on your own server, such as an API it calls, can check the key there, where it can't be removed.
Can I sell my tool as a subscription?
Yes. Use a subscription policy and connect the store: when a Gumroad membership, a Lemon Squeezy subscription or a Stripe subscription ends, the store tells SunLicense and the key is suspended. SunLicense handles the licensing only; what your tool does is up to you.
Is it free?
Yes. The Free plan covers three products, 100 licenses and 10,000 license checks a month, with no credit card. Paid plans start at $5 a month, and your buyers' license checks keep working even if you go over a limit.