SunLicenseSelling Unity, Unreal or Godot tools direct? Give every seat a key.
Sell direct on itch.io, Gumroad or Stripe. Every seat gets a key.
Free plan · No credit card · Set up in minutes
Coding with an AI agent? Paste one prompt- Unity
- Unreal Engine
- Godot
- C# / .NET
- C++
- itch.io
- Gumroad
- Lemon Squeezy
- Stripe
Built for how you sell.
A key per purchase
From the receipt, the checkout or itch.io.
Seats, not shared repos
1, 3 or 10 machines per license.
TOO_MANY_MACHINESC# for Unity
A no-dependency .NET SDK; REST for Unreal, Godot.
.NET Standard 2.0Refunds switch it off
Gumroad, Lemon Squeezy, Payhip and Stripe.
Offline when needed
Signed license files verify with no connection.
Sentinel spots leaks
Keys on too many machines, key guessers.
Lite & StandardLive before your next release.
- 1Create a free account
- 2Connect your store
- 3Check from your editor
using System.Collections.Generic;
using SunLicense; // .NET Standard 2.0, no dependencies
using UnityEditor;
using UnityEngine;
public static class LicenseCheck {
static readonly SunLicenseClient Client = new SunLicenseClient(
"https://api.sunlicense.com", token: "slk_..."); // validation-only key
public static async void Check(string key) {
var result = await Client.ValidateAsync(key, new Dictionary<string, string> {
["host"] = SystemInfo.deviceUniqueIdentifier, // one seat per machine
});
EditorPrefs.SetBool("SplineTool.Pro", result.IsValid);
}
}Questions, answered.
Can I use SunLicense for tools on the Unity Asset Store or Fab?
Those stores have their own license terms and EULAs, and SunLicense doesn't connect to them, so follow their rules for anything you sell there. SunLicense is for tools you sell directly: on itch.io, Gumroad, Lemon Squeezy, Payhip or your own Stripe checkout.
Does the .NET SDK work in Unity?
Yes. The SunLicense package on NuGet targets .NET Standard 2.0 and has no dependencies, so its DLL goes straight into your project (or install it with a NuGet tool for Unity). Call ValidateAsync with the key and a machine id such as SystemInfo.deviceUniqueIdentifier.
How do Unreal plugins and Godot add-ons check a key?
With the REST API: POST https://api.sunlicense.com/api/v1/validate with your API key as a Bearer token and a JSON body holding licenseKey and fingerprint. The JSON answer has valid, a code such as TOO_MANY_MACHINES, and the machines used. FHttpModule in Unreal C++ and HTTPRequest in GDScript both make that call in a few lines.
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 license checks keep working even if you go over a limit.