License and protect your software

Issue software license keys, bind them to devices, and validate them with tamper-proof signed responses that defeat fake license servers — for Python and any language.

Get started free · Read the guides

# pip install pylicensify
from pylicensify import LicenseClient
client = LicenseClient(public_key="YOUR_PUBLIC_KEY")
if client.validate("PY-XXXXXXXXXXXXXXXX"):
    unlock_app()

Everything you need to license and protect software

How software licensing works with Licers

1. 1. Create a product — Add the software you want to license. Set a custom key prefix and defaults in seconds.
2. 2. Generate license keys — Issue keys with expiry, device limits, and per-key feature entitlements — one at a time or in bulk.
3. 3. Validate in your app — Drop in the SDK or call the REST API. Signed responses mean a fake server can never fake a valid check.

Add license validation in a few lines

Use the official pylicensify Python SDK, or call the REST API from any language. The SDK handles the nonce, the Ed25519 signature check, and replay protection so a cracked "fake server" cannot grant access.

• Signed responses you can trust
• Works online or fully offline
• Feature entitlements per key
• Floating & concurrent sessions

Read the Python integration guide · Documentation

Built to stop software piracy

Most licensing fails to one trick: a fake local server that always says valid. Licers signs every response with a key that never leaves our servers, so your app can verify authenticity — and a forged reply is impossible. Learn how to stop software piracy.

Everything is free

Every feature, unlimited — products, keys, devices, validations, offline files, floating licenses, and webhooks. No plans, no limits, no credit card.

Learn about software licensing

Practical guides on protecting your code. All articles

How to Add License Key Validation to a Python AppHow to Stop Software Piracy Without Losing Your MindHow to Generate a License Key in Python

Frequently asked questions

What is Licers?

Licers is a platform for managing software license keys. You issue keys to customers, bind them to devices, and validate them at runtime with signed responses that a fake server cannot forge. It works with Python and any language over a simple REST API.

Is Licers really free?

Yes. Every feature is currently free and unlimited — products, license keys, devices, validations, offline files, floating licenses, and webhooks. No credit card required.

What programming languages does it support?

Licers has an official Python SDK (pip install pylicensify) and a plain REST API that works from any language — you can validate a key with a single HTTP request.

How does signed validation stop piracy?

Every validation response is signed with a private key that never leaves the server. Your app verifies it with an embedded public key, so a cracker who redirects your app to a fake server cannot forge a valid response.

Do I need to run my own server?

No. Licers runs on Cloudflare's global edge and hosts the validation API for you. You call it from your app; there is no infrastructure to manage.

Can I validate licenses offline?

Yes. You can issue signed offline license files that verify locally against your public key with no network connection — ideal for air-gapped machines.