The short version is "don't bother".

The only way to 'limit' usage is to have the plugin authorize itself against your permissions database, where you store your customer's purchase details. This means you'll need to maintain a site permanently that will answer the authorization calls from plugin installs.

If you're not willing to make that commitment, don't bother with trying to limit usage.

If you're still determined to do it, you'll need to come up with a way that authenticates the plugin and either performs the needed operations on your server ( like Akismet does ) or deliver essential coding via your server that can't be sniffed and copied. Not an easy task.

kengperapol,

I would certainly protect your code and investment......

Just because people can break into all of our homes DOES NOT mean we simply leave our doors unlocked.... We lock our doors because it keeps the vast majority of people out.....

That is what these encryption and licensing programs do.... They keep the vast majority of people from "sharing it" or using it on "extra" sites.....

You could use two different approaches......

First, you could use something like CODELOCK Tracker V2. It allows you to monitor, activate and deactivate remotely.... It also encrypts the PHP and it is compatabile with Zen Encoder and other encoders.... It is $155... You would need to host the license server.... You can find all the details at the following:

CodeLock V2.0 - The PHP / HTML script and code Encryptor

Second, you could use something like CODELOCK V2.7 + Engine... This encrypts your files AND allows you to create time limited versions.... With this, you could simply give your users the time limited version at time of purchase..... After your money back guarantee period has passed, you simply send them an unlock key.... It never has to contact your server..... You would not need to host a license server.... It is $55...You can find all the details at the following:

CodeLock V2.0 - The PHP / HTML script and code Encryptor

If you have any questions about licensing schemes, please fire away!

God Bless,

Rich

P.S. I have NO financial interest or affiliation with this company. I found this while I was researching a while back.

Keng,

In the latter case, I would simply upload the time limited version to WarriorPlus. Then, when your money back guarantee expires, send them the actual key.

No protection system is perfect. But, it will slow down the thieves.

Make sure you have a clause in your license agreement stating it cannot be decompiled or reverse engineered for any reason.

Take Care,

Rich

P.S. - Keng, get moving! Sell your plugin and make a boat load of cash!!!!

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I recommend license protection for all your plugins, here is my approach:
1. Use zend guard or ioncube to encode some of php files. Some users don't like this but this will surely protects your script.

2. If you can code then create custom licensing server. Here is the idea:
- Create subdomain for your licensing server and put the licensing files there example: http://authentication.mydomain.com. All your licensing call will be queried to this url.
- Create table to handle licensing based on name, email, and transaction id
- Whenever someone buys, insert their detail into this table, this means they are valid user
- When use plugin, they must input their details, and your scripts call your licensing server to check whether he is valid user or not, if valid then proceed

Hope this helps.

Useful information about wordpress plugin.i get really nice knowledge form this thread .thanks for sharing.

Hey, I've just created a wordpress plugin licensing system.
You can find out more about it at: Wordpress Plugin Licensing

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^^^ his account suspended
LOL

first of all WordPress is GPL this whole licensing for developers / 1 site / multi site is BS

If you build in WP plugin people who buy can do with it what they want as per GPL license.

If you want to try to stop them you are of course free to try but it will draw bad blood (speaking for myself here of course as I can't speak for others).

Then some system that is going to track, thus report back to your servers when I buy a product like a WP plugin.. HELL NO I wouldn't care how good your product is I would NEVER buy that.

I agree with SteveJohnson, just don't bother trying to Limit usage. Better focus on superb support that people out of respect stay with you and are happy to pay for it.

I have recently started releasing Pro versions of my free plugins.

I don't plan on using a license management system. For plugins that are not that expensive people will buy them and won't waste time to save $20.

Another good reason to buy for the provider is that the code will be a good quality and will not some spyware.

When my plugin checks for updates it will show when an update is available.
If the person hadn't purchased the script the automatic update will not be available for him/her.

I was wondering should I release my license/plugin update system as open source?