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So I'm remaking a product and was approaching qt about the commercial version. The rep was very insistent that I can not develop an internal prototype using th

So I'm remaking a product and was approaching qt about the commercial version. The rep was very insistent that I can not develop an internal prototype using the open source license and then move to the commercial license. So that makes qt pretty unattractive to me since I have to pony up cash and hope it's good. What I would like is something like electron that can run on a frame buffer. What's the current state of the art for a html5 based embedded interface?

lultimouomo 10y ago
From my understanding of the licensing, that doesn't sound right. The internal product will be subject to the LGPL, but eve if that's a problem you only need to make sure you don't distribute it to anyone so that no one can ask you to oblige to the license.
- joezydeco 10y ago
  No, that's always been a quirk of the Qt licensing. If you intend to launch a closed-source* product at some future date and pay the per-unit licensing fees, the developer needs a seat license from day one. (* closed-source or code that statically links in the Qt libraries)
  - lultimouomo 10y ago
    That sounds like FUD* - Qt's LGPL is LGPL without modifications, so it does not have any quirk. Is it written in the commercial license that you cannot buy it if you have used the LGPL license? * Not accusing you of course; I'm totally convinced that it can come from a misguided sales rep trying to close a deal as early as possible.
    - joezydeco 10y ago
      The LGPL thing is not really the issue here. It's how Trolltech/Nokia/Digia/QtCo approached the payment of a commercial license. It's always been explained to me by the sales people that "you cannot switch licensing models mid-stream". So if you're planning to go commercial, you start commercial. It's not really about closing the deal as much as making sure the Trolltech developers were paid during the time you needed their support.
      - loeg 10y ago
        > It's not really about closing the deal as much as making sure the Trolltech developers were paid during the time you needed their support. The OSS license doesn't grant you any support from Trolltech, does it?
        joezydeco 10y ago
        Of course not. But I could totally see Trolltech getting critical bugfix requests from people "promising" to pay the commercial license once they launch. I would totally understand the response eventually turning into "yeah, we'll fix your bug, but put your money where your mouth is", which is where they are today.
      - Grishnakh 10y ago
        But do you even need a commercial license to sell your product commercially? It's LGPL, so surely you can just keep the Qt library LGPL. If you're not changing anything at all in Qt (and you really shouldn't be...), and you don't care about getting support (the docs are good enough for you), then why do you need a commercial license at all?
        distances 10y ago
        There are still some cases where you need a license, like Qt for Device Creation (https://www.qt.io/qt-for-device-creation https://www.qt.io/qt-for-device-creation). Or perhaps you need static linking, or want to include some Qt code in the app proper for one reason or another.
        Grishnakh 10y ago
        Ok, but if you stick with dynamic linking and don't insert Qt code into your app, then you don't need a commercial license, right? Why would you insert Qt code in your app anyway? That kinda defeats the point of using a library. As for static linking, why would you opt for this over dynamic linking anyway? Dynamic linking is better since other applications can share the libraries. Static linking on a PC platform is basically a hack for poor library management. As for Qt for Device Creation, I looked through that and didn't see why you'd need a license there, unless they're selling optional components or plug-ins which are not LGPL licensed (which appears to be the case with things like "Qt Quick 2D Renderer" and "Qt Virtual Keyboard"). I even tried out the questionnaire at www.qt.io/download: if you select "Commercial deployment" for development and then say that you're doing dynamic linking, don't have any concerns about reverse-engineering, and can comply with the LGPL, it recommends you use the open-source LGPL'ed version.
    - distances 10y ago
      Qt-as-the-company has always made it very clear that you can't switch your Qt LGPL/GPL project to a commercial one if you didn't start with the commercial Qt license from the beginning. You're right, it does sound a bit nasty. No, I haven't read the license myself. It's been brought up multiple times on official Qt blog comments and mailing lists, though. Edit: checked it now, and it's clearly written at https://www.qt.io/faq/ https://www.qt.io/faq/, "Developing with a Commercial License": > Q: If I have started development of a project using the open source version (LGPL), can I later purchase a commercial version of Qt and move my code under that license? > A: This is not permitted without written consent from The Qt Company. If you have already started the development with an open-source version of Qt, please contact The Qt Company to resolve the issue.
      - joezydeco 10y ago
        It's not standard and it's not pleasant to most ears, but I think over the last 20 (!) years of development the Trolltech guys have tried to make sure they could advance Qt and make a living doing it. I respect that a lot. OSS was a completely different animal back when this thing started. And it was forward thinking to avoid the whole problem with people demanding free support and bugfixes for open-source code.
        distances 10y ago
        Not saying that this is wrong, just that it's no wonder if they think this to be FUD if one isn't familiar with the rule. As for the reasoning, a customer developing their product for years in-house and switching to commercial just before releasing would definitely place Qt financing in a shaky ground when compared to traditional commercial frameworks.
      - Dlotan 10y ago
        At my last company we had this situation. But they are more than happy to sort this out for free if you take a license for the next 2 years.
        distances 10y ago
    - karmicthreat 10y ago
      I found the applicable text: https://www.qt.io/terms-conditions/ https://www.qt.io/terms-conditions/ *NOTE: If Licensee, or another third party, has, at any time, developed or distributed all (or any portions of) the Application(s) using an open source version of Qt licensed under the terms of the GNU Lesser General Public License, version 2.1 or later (“LGPL”) or the GNU General Public License version 2.0 or later (“GPL”), Licensee may contact The Qt Company via email to address sales@qt.io to ask for the necessary permission to combine such development work with the Licensed Software. The Qt Company shall evaluate Licensee´s request, and respond to the request with estimated license costs and other applicable terms and details relating to the permission for the Licensee, depending on the actual situation in question. Copies of the licenses referred to above are located at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html, http://www.gnu.org/licenses/lgpl-3.0.html http://www.gnu.org/licenses/lgpl-3.0.html, http://www.fsf.org/licensing/licenses/info/GPLv2.html http://www.fsf.org/licensing/licenses/info/GPLv2.html, and http://www.gnu.org/copyleft/gpl-3.0.html http://www.gnu.org/copyleft/gpl-3.0.html. So really the questionable term isn't an additional term on the LGPL, it is on the commercial license.
      - lultimouomo 10y ago
        That is very interesting. Note that they are not precluding you to switch, but they do reserve the right to sell or not sell to you the commercial license after you've used the LGPL. It sounds like an empty threat to me (if you talk to the sales rep and say "I have an internal prototype and I would like to buy the commercial license to finish and distribute it", will they say no?), but one should definitely consider this before choosing to try the LGPL version for early product development. I think this is mostly meant to avoid having a team of 50 develop an internal version based on LGPL, and then a team of 1 maintain the commercial version, paying a single developer seat. Note that you can still do a throw away prototype without problems. Some say you should in any case!
        jschwartzi 10y ago
        It's not an empty threat so much as it's an opportunity for them to gouge you later when your product is already highly dependent on their product.
- karmicthreat 10y ago
  Yea, that was my understanding of it also. I think they are trying to make the argument that once the your code is written under LGPL, its LGPL forever and can't have another license.
  - lultimouomo 10y ago
    Your code is never under the LGPL though; you are free to license your code as you please. It's the binary you release that being linked to a LGPL library is subject to its conditions.
  - fs111 10y ago
    If that was true, then QT would violate this principle itself and could not sell you a commercial license.
    - adrianlmm 10y ago
      Qt doesn't violate this principle, cause it is double licensed, Digia is just not using the LGPL version.
ausjke 10y ago
Electron might not be "fast" enough for many serious GUI applications? That been said, I also am struggling with finding a non-Java cross-platform GUI dev platform. The selection pool boils down to between QT and Electron indeed these days.
- jventura 10y ago
  You are correct. The only serious frameworks nowadays are Qt or Electron if you're targeting the cross-platform desktop. There's also wxwidgets, although its python 3 bindings are still being built. Personally, I'm keeping my eye open on libui (https://github.com/andlabs/libui/ https://github.com/andlabs/libui/) as it is already possible to do some basic things with it. However, it is pretty much in alpha state and I'm slowly writing the Python bindings for it at https://github.com/joaoventura/pylibui/ https://github.com/joaoventura/pylibui/. The thing that I like in the libui is that it is a thin wrapper around platform specific frameworks. Therefore, the library is very small (some 340 KB) and it's as native as the underlying platform calls are.. Regarding Electron, I am writing an application on it, but it is too god damn heavy in terms of memory, disk space and boot time, and web front-end development is absolute chaos these days. Although I'm currently writing my app on it, it is mostly an MVP as I want to make pylibui/libui usable enough to switch to a pure desktop cross-platform library asap..
  - c-smile 10y ago
    "Regarding Electron, I am writing an application on it, but it is too god damn heavy in terms of memory, disk space and boot time," Try Sciter HTML/CSS engine then (http://sciter.com http://sciter.com). It is a monolitic DLL (4-8 Mb) without external dependencies. Works on Win/Lin/OSX and even on Raspberry Pi 2 - http://sciter.com/sciter-on-raspberry-pi-2/ http://sciter.com/sciter-on-raspberry-pi-2/
    - jventura 10y ago
      Thanks for the suggestion, I didn't knew about this before! So I've tried it, the lib is small (~9MB on OS X), it renders pretty fast and has python bindings which is quite great. However it lacks in some areas, such as the scrolling which is quite bad, and it does not render the SVG files that I'd need it to render (tiny SVG spec, but lots of defs and rotations). I'm still going to look better into it since I can use Cairo and CairoSVG to convert my SVGs to PNGs, but I still do not know how well it renders some css rules, fonts, etc..
Nokinside 10y ago
Why can't you ship commercial version with LGPL? It's LGPL not GPL? I mean, if you don't need to modify the Qt-library, you don't need commercial license. You just need to provide link to the Qt-sources.
- FigBug 10y ago
  You also need to make it so the user can replace the Qt binaries with a later / modified version which may not be possible on an embedded device.
  - ronjouch 10y ago
    Really? Why? Is this something applicable to all commercial software using GPL/LGPL components? Which clause of the GPL/LGPL makes you say that, or is there prior judgement that resulted in making such a demand?
    - ori_b 10y ago
      This one: d) Do one of the following: 0) Convey the Minimal Corresponding Source under the terms of this License, and the Corresponding Application Code in a form suitable for, and under terms that permit, the user to recombine or relink the Application with a modified version of the Linked Version to produce a modified Combined Work, in the manner specified by section 6 of the GNU GPL for conveying Corresponding Source. 1) Use a suitable shared library mechanism for linking with the Library. A suitable mechanism is one that (a) uses at run time a copy of the Library already present on the user's computer system, and (b) will operate properly with a modified version of the Library that is interface-compatible with the Linked Version.
      - 0xfeba 10y ago
        > Will operate properly with a modified version Sounds like all you have to do is prove your build on your dev machine works with newer versions. Up to the user to update the library on the target machine!
sigzero 10y ago
What's his reasoning? As long as you purchase the commercial license prior to releasing why should they care?
- CamperBob2 10y ago
  Agreed, that policy is utterly nuts. The incentives for me to comply with those terms are nonexistent, which is never a sign of a good contract.
cplease 10y ago
I love it when commercial software developers complain about having to pay for software. How dare Qt demand that others pay them before developing a commercial product using their code?
- karmicthreat 10y ago
  Or maybe I just want a prototype to prove out a concept and software stack. Rather than just blindly throwing money at a problem. I have no problem paying Qt. I'm just unwilling to do it until I know its the direction I want to go. The current Qt licensing structure adds friction to my making that decision.
  - cplease 10y ago
    Of course it adds friction. It's supposed to add friction. They wrote the code, they're a going concern, if you're going to pay they want you to commit and pay, not "prove out the concept" for free. Qt will give you a license for prototyping, you're just not willing to pay it. Most commercial vendors won't give you their entire product for free until your own product is half-built. Qt is different; they offer an entire free product. You want to have your cake and eat it too.
    - karmicthreat 10y ago
      The license for prototyping seems to be the same one for release. And Qt isn't offering me a free product, their terms are pay then develop your software. At least in my context. In any event the only issue is the weird quirk of the Qt commercial license preventing you from switching to commercial from LGPL. Which I and apparently a few other people in the thread really didn't get at first.
      - cplease 10y ago
        > The license for prototyping seems to be the same one for release. And Qt isn't offering me a free product, their terms are pay then develop your software. At least in my context. Their standard Qt for Application Development license gives you a free 30 day evaluation period. Also, I don't think any of this encompasses simply examining the free product without use in product development, e.g., reading the APIs, documentation, and source code. That's a lot of freebies, that you don't necessarily get with other commercial products. > In any event the only issue is the weird quirk of the Qt commercial license preventing you from switching to commercial from LGPL. Which I and apparently a few other people in the thread really didn't get at first. There's no weird quirk. As they state, "If you have already started the development with an open-source version of Qt, please contact The Qt Company to resolve the issue." If you have money, they will take your money. But if you want to develop a commercial product and use Qt up front then you have to budget for it. If you can't afford it then use something else. No one is holding a gun to your head forcing you to develop a proprietary product with Qt.

lultimouomo 10y ago

From my understanding of the licensing, that doesn't sound right. The internal product will be subject to the LGPL, but eve if that's a problem you only need to make sure you don't distribute it to anyone so that no one can ask you to oblige to the license.

joezydeco 10y ago
No, that's always been a quirk of the Qt licensing. If you intend to launch a closed-source* product at some future date and pay the per-unit licensing fees, the developer needs a seat license from day one. (* closed-source or code that statically links in the Qt libraries)
- lultimouomo 10y ago
  That sounds like FUD* - Qt's LGPL is LGPL without modifications, so it does not have any quirk. Is it written in the commercial license that you cannot buy it if you have used the LGPL license? * Not accusing you of course; I'm totally convinced that it can come from a misguided sales rep trying to close a deal as early as possible.
  - joezydeco 10y ago
    The LGPL thing is not really the issue here. It's how Trolltech/Nokia/Digia/QtCo approached the payment of a commercial license. It's always been explained to me by the sales people that "you cannot switch licensing models mid-stream". So if you're planning to go commercial, you start commercial. It's not really about closing the deal as much as making sure the Trolltech developers were paid during the time you needed their support.
    - loeg 10y ago
      > It's not really about closing the deal as much as making sure the Trolltech developers were paid during the time you needed their support. The OSS license doesn't grant you any support from Trolltech, does it?
      - joezydeco 10y ago
        Of course not. But I could totally see Trolltech getting critical bugfix requests from people "promising" to pay the commercial license once they launch. I would totally understand the response eventually turning into "yeah, we'll fix your bug, but put your money where your mouth is", which is where they are today.
    - Grishnakh 10y ago
      But do you even need a commercial license to sell your product commercially? It's LGPL, so surely you can just keep the Qt library LGPL. If you're not changing anything at all in Qt (and you really shouldn't be...), and you don't care about getting support (the docs are good enough for you), then why do you need a commercial license at all?
      - distances 10y ago
        There are still some cases where you need a license, like Qt for Device Creation (https://www.qt.io/qt-for-device-creation https://www.qt.io/qt-for-device-creation). Or perhaps you need static linking, or want to include some Qt code in the app proper for one reason or another.
        Grishnakh 10y ago
        Ok, but if you stick with dynamic linking and don't insert Qt code into your app, then you don't need a commercial license, right? Why would you insert Qt code in your app anyway? That kinda defeats the point of using a library. As for static linking, why would you opt for this over dynamic linking anyway? Dynamic linking is better since other applications can share the libraries. Static linking on a PC platform is basically a hack for poor library management. As for Qt for Device Creation, I looked through that and didn't see why you'd need a license there, unless they're selling optional components or plug-ins which are not LGPL licensed (which appears to be the case with things like "Qt Quick 2D Renderer" and "Qt Virtual Keyboard"). I even tried out the questionnaire at www.qt.io/download: if you select "Commercial deployment" for development and then say that you're doing dynamic linking, don't have any concerns about reverse-engineering, and can comply with the LGPL, it recommends you use the open-source LGPL'ed version.
  - distances 10y ago
    Qt-as-the-company has always made it very clear that you can't switch your Qt LGPL/GPL project to a commercial one if you didn't start with the commercial Qt license from the beginning. You're right, it does sound a bit nasty. No, I haven't read the license myself. It's been brought up multiple times on official Qt blog comments and mailing lists, though. Edit: checked it now, and it's clearly written at https://www.qt.io/faq/ https://www.qt.io/faq/, "Developing with a Commercial License": > Q: If I have started development of a project using the open source version (LGPL), can I later purchase a commercial version of Qt and move my code under that license? > A: This is not permitted without written consent from The Qt Company. If you have already started the development with an open-source version of Qt, please contact The Qt Company to resolve the issue.
    - joezydeco 10y ago
      It's not standard and it's not pleasant to most ears, but I think over the last 20 (!) years of development the Trolltech guys have tried to make sure they could advance Qt and make a living doing it. I respect that a lot. OSS was a completely different animal back when this thing started. And it was forward thinking to avoid the whole problem with people demanding free support and bugfixes for open-source code.
      - distances 10y ago
        Not saying that this is wrong, just that it's no wonder if they think this to be FUD if one isn't familiar with the rule. As for the reasoning, a customer developing their product for years in-house and switching to commercial just before releasing would definitely place Qt financing in a shaky ground when compared to traditional commercial frameworks.
    - Dlotan 10y ago
      At my last company we had this situation. But they are more than happy to sort this out for free if you take a license for the next 2 years.
      - distances 10y ago
  - karmicthreat 10y ago
    I found the applicable text: https://www.qt.io/terms-conditions/ https://www.qt.io/terms-conditions/ *NOTE: If Licensee, or another third party, has, at any time, developed or distributed all (or any portions of) the Application(s) using an open source version of Qt licensed under the terms of the GNU Lesser General Public License, version 2.1 or later (“LGPL”) or the GNU General Public License version 2.0 or later (“GPL”), Licensee may contact The Qt Company via email to address sales@qt.io to ask for the necessary permission to combine such development work with the Licensed Software. The Qt Company shall evaluate Licensee´s request, and respond to the request with estimated license costs and other applicable terms and details relating to the permission for the Licensee, depending on the actual situation in question. Copies of the licenses referred to above are located at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html, http://www.gnu.org/licenses/lgpl-3.0.html http://www.gnu.org/licenses/lgpl-3.0.html, http://www.fsf.org/licensing/licenses/info/GPLv2.html http://www.fsf.org/licensing/licenses/info/GPLv2.html, and http://www.gnu.org/copyleft/gpl-3.0.html http://www.gnu.org/copyleft/gpl-3.0.html. So really the questionable term isn't an additional term on the LGPL, it is on the commercial license.
    - lultimouomo 10y ago
      That is very interesting. Note that they are not precluding you to switch, but they do reserve the right to sell or not sell to you the commercial license after you've used the LGPL. It sounds like an empty threat to me (if you talk to the sales rep and say "I have an internal prototype and I would like to buy the commercial license to finish and distribute it", will they say no?), but one should definitely consider this before choosing to try the LGPL version for early product development. I think this is mostly meant to avoid having a team of 50 develop an internal version based on LGPL, and then a team of 1 maintain the commercial version, paying a single developer seat. Note that you can still do a throw away prototype without problems. Some say you should in any case!
      - jschwartzi 10y ago
        It's not an empty threat so much as it's an opportunity for them to gouge you later when your product is already highly dependent on their product.
karmicthreat 10y ago
Yea, that was my understanding of it also. I think they are trying to make the argument that once the your code is written under LGPL, its LGPL forever and can't have another license.
- lultimouomo 10y ago
  Your code is never under the LGPL though; you are free to license your code as you please. It's the binary you release that being linked to a LGPL library is subject to its conditions.
- fs111 10y ago
  If that was true, then QT would violate this principle itself and could not sell you a commercial license.
  - adrianlmm 10y ago
    Qt doesn't violate this principle, cause it is double licensed, Digia is just not using the LGPL version.

ausjke 10y ago

Electron might not be "fast" enough for many serious GUI applications? That been said, I also am struggling with finding a non-Java cross-platform GUI dev platform. The selection pool boils down to between QT and Electron indeed these days.

jventura 10y ago
You are correct. The only serious frameworks nowadays are Qt or Electron if you're targeting the cross-platform desktop. There's also wxwidgets, although its python 3 bindings are still being built. Personally, I'm keeping my eye open on libui (https://github.com/andlabs/libui/ https://github.com/andlabs/libui/) as it is already possible to do some basic things with it. However, it is pretty much in alpha state and I'm slowly writing the Python bindings for it at https://github.com/joaoventura/pylibui/ https://github.com/joaoventura/pylibui/. The thing that I like in the libui is that it is a thin wrapper around platform specific frameworks. Therefore, the library is very small (some 340 KB) and it's as native as the underlying platform calls are.. Regarding Electron, I am writing an application on it, but it is too god damn heavy in terms of memory, disk space and boot time, and web front-end development is absolute chaos these days. Although I'm currently writing my app on it, it is mostly an MVP as I want to make pylibui/libui usable enough to switch to a pure desktop cross-platform library asap..
- c-smile 10y ago
  "Regarding Electron, I am writing an application on it, but it is too god damn heavy in terms of memory, disk space and boot time," Try Sciter HTML/CSS engine then (http://sciter.com http://sciter.com). It is a monolitic DLL (4-8 Mb) without external dependencies. Works on Win/Lin/OSX and even on Raspberry Pi 2 - http://sciter.com/sciter-on-raspberry-pi-2/ http://sciter.com/sciter-on-raspberry-pi-2/
  - jventura 10y ago
    Thanks for the suggestion, I didn't knew about this before! So I've tried it, the lib is small (~9MB on OS X), it renders pretty fast and has python bindings which is quite great. However it lacks in some areas, such as the scrolling which is quite bad, and it does not render the SVG files that I'd need it to render (tiny SVG spec, but lots of defs and rotations). I'm still going to look better into it since I can use Cairo and CairoSVG to convert my SVGs to PNGs, but I still do not know how well it renders some css rules, fonts, etc..

Nokinside 10y ago

Why can't you ship commercial version with LGPL? It's LGPL not GPL? I mean, if you don't need to modify the Qt-library, you don't need commercial license. You just need to provide link to the Qt-sources.

FigBug 10y ago
You also need to make it so the user can replace the Qt binaries with a later / modified version which may not be possible on an embedded device.
- ronjouch 10y ago
  Really? Why? Is this something applicable to all commercial software using GPL/LGPL components? Which clause of the GPL/LGPL makes you say that, or is there prior judgement that resulted in making such a demand?
  - ori_b 10y ago
    This one: d) Do one of the following: 0) Convey the Minimal Corresponding Source under the terms of this License, and the Corresponding Application Code in a form suitable for, and under terms that permit, the user to recombine or relink the Application with a modified version of the Linked Version to produce a modified Combined Work, in the manner specified by section 6 of the GNU GPL for conveying Corresponding Source. 1) Use a suitable shared library mechanism for linking with the Library. A suitable mechanism is one that (a) uses at run time a copy of the Library already present on the user's computer system, and (b) will operate properly with a modified version of the Library that is interface-compatible with the Linked Version.
    - 0xfeba 10y ago
      > Will operate properly with a modified version Sounds like all you have to do is prove your build on your dev machine works with newer versions. Up to the user to update the library on the target machine!

sigzero 10y ago

What's his reasoning? As long as you purchase the commercial license prior to releasing why should they care?

CamperBob2 10y ago
Agreed, that policy is utterly nuts. The incentives for me to comply with those terms are nonexistent, which is never a sign of a good contract.

cplease 10y ago

I love it when commercial software developers complain about having to pay for software. How dare Qt demand that others pay them before developing a commercial product using their code?

karmicthreat 10y ago
Or maybe I just want a prototype to prove out a concept and software stack. Rather than just blindly throwing money at a problem. I have no problem paying Qt. I'm just unwilling to do it until I know its the direction I want to go. The current Qt licensing structure adds friction to my making that decision.
- cplease 10y ago
  Of course it adds friction. It's supposed to add friction. They wrote the code, they're a going concern, if you're going to pay they want you to commit and pay, not "prove out the concept" for free. Qt will give you a license for prototyping, you're just not willing to pay it. Most commercial vendors won't give you their entire product for free until your own product is half-built. Qt is different; they offer an entire free product. You want to have your cake and eat it too.
  - karmicthreat 10y ago
    The license for prototyping seems to be the same one for release. And Qt isn't offering me a free product, their terms are pay then develop your software. At least in my context. In any event the only issue is the weird quirk of the Qt commercial license preventing you from switching to commercial from LGPL. Which I and apparently a few other people in the thread really didn't get at first.
    - cplease 10y ago
      > The license for prototyping seems to be the same one for release. And Qt isn't offering me a free product, their terms are pay then develop your software. At least in my context. Their standard Qt for Application Development license gives you a free 30 day evaluation period. Also, I don't think any of this encompasses simply examining the free product without use in product development, e.g., reading the APIs, documentation, and source code. That's a lot of freebies, that you don't necessarily get with other commercial products. > In any event the only issue is the weird quirk of the Qt commercial license preventing you from switching to commercial from LGPL. Which I and apparently a few other people in the thread really didn't get at first. There's no weird quirk. As they state, "If you have already started the development with an open-source version of Qt, please contact The Qt Company to resolve the issue." If you have money, they will take your money. But if you want to develop a commercial product and use Qt up front then you have to budget for it. If you can't afford it then use something else. No one is holding a gun to your head forcing you to develop a proprietary product with Qt.