Ozeki VoIP SIP SDK licensing FAQ

I am interested in your Ozeki VoIP SIP SDK. How can I purchase a license?

You can purchase an Ozeki VoIP SIP SDK license on the How to buy page by clicking on the Order button next to the selected SDK license. This will bring up a form on which you can select the payment method you prefer. You can purchase the Ozeki VoIP SIP SDK license paying via wire transfer or by credit card. You will also get a reference number, which is used to identify your order.
After we receive the payment, you will receive a license code in e-mail. You can use this license code when you develop your products or services.
You can place an order on the How to buy page.
For more information regarding the payment procedure, please contact us, and we will provide you assistance for purchasing.

What is your licensing based on?

Ozeki VoIP SIP SDKs licensing is based on the number of the simultaneous calls you wish to handle. For example if you wish to build a softphone that can handle two calls simultaneously, you need the "Ozeki SIP SDK for .NET - 2 simultaneous calls" license. If you build your softphone with this license, your softphone can be used in many places at the same time to make calls.

What is the licensing definition of a simultaneous call?

By a call we mean a conversation between two people.
For example, if you build a softphone, which is used by John, and if John is talking to Jane, and John is talking to Mary at the same time with this softphone, this would count as two calls. John can use voice and video in both calls. For this you would need the "Ozeki SIP SDK for .NET - 2 simultaneous calls" license, when you create this softphone. You can distribute this softphone to as many people as you want. For example if you give it to "John" and you give it to "Jack" and "Jim" and "Frank". All of them can talk with two girls at the same time, and you only had to buy one "Ozeki VoIP SIP SDK - 2 simultaneous call" license to build your softphone.
Another example would be an Interactive Voice Response (IVR) system. If you want to make system, that can handle 100 calls from customers at the same time, you need the "Ozeki SIP SDK for .NET - 128 simultaneous calls" license. With this license you can have 128 customers navigating in the IVR menu.

How do simultaneous calls in the license relate to SIP accounts?

Licensing is based on calls and SIP accounts.
When you decide on purchasing an Ozeki VoIP SIP SDK license, you can decide how many SIP accounts you wish to use and how many simultaneous calls you wish to make, and we will find the most suitable license for your goals.

After purchasing a license, do I have to pay any royalties or license fees to Ozeki when I sell the copies of my product?

No, you don't have to pay any royalty or any other fee to us. A purchased license can be used to build a single product, which (along with its subsequent versions) can be freely distributed in as many copies as you wish.

Can I distribute my customized VoIP product free of charge?

Yes, you can. After purchasing one Ozeki VoIP SIP SDK license you are free to distribute as many copies of this single product based on our SDK as you wish with no additional payment.

Can I get a proforma invoice prior to the order?

Yes, you can.
If you need a proforma invoice before you place an order, please let us know, and we can send you one. You can request a proforma invoice by sending us your billing information and your mailing address. You will receive the final invoice after you have purchased the product.

Will I get an invoice?

Yes, of course.
When you purchase the product please send us the billing information, and the mailing address in e-mail and we will send you the invoice by postal mail. If you have any special requirements, regarding what kind of extra information should be written on the invoice, please let us know.

Can I upgrade my purchased license to a higher level? If yes, how?

Yes, you can. In the future you can upgrade the purchased software license to higher capacity if you pay the price difference between the price of your license and the price of the higher capacity license plus some administration fee.

Is there a "maintenance" or "support" fee per year for the developer licenses?

The price of the product includes three months of free technical standard support and one year of free version updates. Support for additional periods can be purchased. We can provide technical support by e-mail, telephone or MSN messenger.

Do you sell the source code of Ozeki VoIP SIP SDK?

Yes, we do. The full source code is available in the "Ozeki SIP SDK for .NET - 10000 simultaneous calls" license package.

If I buy the source code, can I change the codes and should I release those modified codes to Ozeki?

After buying the source code, you can change the codes freely and you do not have to release those codes to Ozeki.

Why is there a limitation on the number of simultaneous calls? What if I would like to handle unlimited number of calls?

The limitations mentioned in our price list are licensing limitations, not technology limitations. They are there, because we provide technical support and assistance to our customers. It takes more resources from us to support a system with several thousand simultaneous calls, than to support a system that makes only a few calls at a time and this difference is reflected in the prices of the standard licenses.
Our SDK can be used to build systems that support more calls, for example it is used in the www.beewebphone.com service, which can be scaled up to hundreds of millions of calls. If you wish to build a high capacity, scalable system, please consult with us, and ask for a custom license.

How many copies of my product can I distribute with only one license key?

You can distribute as many copies as you want but only for one application or one service.

If I would like to create an application which will be used by a large number of customers, how many license keys do I need to buy?

A single license key is enough for a single product or service. The number of users does not affect the licensing of Ozeki VoIP SIP SDK. With an "Ozeki SIP SDK for .Net - Single call" license, all of your users will be able to handle one call at a time.

Do I need separate licenses for the build activity (e.g. for the builder machines or the installer builders)?

You can use a license code on one developer workstation only. If you have two software developers (two people) working on different developer workstations, you need to purchase two Ozeki VoIP SIP SDK licenses. In other words one Ozeki VoIP SIP SDK license should be purchased for every computer, that is used for development.

So if I purchase one SDK license can I use it in multiple client system or I need to purchase a license for each client system?

With one license you can use multiple client systems.

Do I need a license per development servers?

If you have a developer workstation and an independent build server, you will need two Ozeki VoIP SIP SDK licenses, one for the developer workstation and one for the build server. One Ozeki VoIP SIP SDK license code can be activated on one physical computer only.

Do I need a license per developer working on my project?

One license is required per application. It does not matter how many developers work on that application.

Do we have to buy a separate license for each version (e.g.,,, ...) of our product?

In case you develop the same application, you do not need a new Ozeki VoIP SIP SDK license upon each version (,,, ...). You would only need a new license if you start to develop a totally new application (e.g. you have developed an IVR first, and then you would like to develop a softphone).

If I want to develop Windows Service with the following requirements: dial number, play wav message, recognize DTFM signals, receive call, one simultaneous call - which license should I buy?

For this purpose you should select Ozeki SIP SDK for .Net - Single call license. This license provides all the enlisted requirements.

I need your SDK only for a private development, not for commercial use. Do you have offers for me?

Yes, we do. If you would not like to build a whole call center, for instance, only create something for personal purposes, you can choose from our standard licenses.

My trial has expired, how can I use your SDK for more time?

The trial version of Ozeki VoIP SIP SDK is freely available on our website. It can be used to test all of the features, however it has some limitations. One of the limitations is that it can be used the software in trial mode for a period of 20 days. If this trial period has expired, you need to purchase a licensed SDK in order to use it for unlimited time. When you purchase the Ozeki VoIP SIP SDK license, you will receive a registration code which helps you to activate the SDK and remove the limitations.

I am looking for a freeware license.

Our solution is a commercial Software Development Kit to quickly make VoIP applications for your company or distribute it to your customers under your brand. The Ozeki SIP SDK license cost is a one-time fee. You can use the purchased license for as long as you wish (forever) without paying any additional fee.

What do you mean by "single product". Does it mean that we can use it only once to design a single or first product.

We mean by 'Single product' that one Ozeki VoIP SIP SDK standard license can be used for building one product (for example, a softphone). A service that you wish to launch based on the SDK can also be considered as a product. This 'single product' or single service (along with its subsequent versions) can be freely distributed in as many copies as you wish without paying any royalties or license fees to Ozeki. The service can be operated on arbitrary places.
The professional licenses of Ozeki VoIP SIP SDK allow to build 3 products/services while the enterprise licenses have no limitation for the number of products or services.

If you have any question or need assistance, please contact us at info@voip-sip-sdk.com