Newbie zend license question

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Newbie here trying out php first time.

Just haven't found a definitive answer about the true nature of
PHP license and the zend license in the short faqs at

1. Is PHP the interpreter released under an open source license?

2. And what does zend got to do with it - its not open source - i.e.
   do I need it to run a apache/php/mysql system to
   create say a wiki or an online photo album?

Basically I don't want to develop a whole buch of php thinking its oss
and then find I have to fork out for licenses.

Re: Newbie zend license question

You can find basic details on PHP and Zend's licensing here: /

1. Yes PHP is open source, you may modify it as you wish. But as long
as you're still using any parts of PHP you have to include their
copyright in your source when distributed.

2. Zend is the scripting engine that PHP runs on. If you download the
latest PHP installments you shouldn't have to worry about anything to
do with Zend, it should run just fine without you having to configure

The only two reasons you really need to consider the Zend engine are 1)
when you're building a commercial application around the Zend engine
you would have to contact Zend for licensing info, and 2) if you
publish patches to Zend, they can use them royalty-free at anytime.

Obviously there are differences between this and the latest license
agreement, so I advise you to read them via the link posted above. But
if you're just starting with PHP and making scripts and pages with it,
don't worry about anything. As long as you're developing PHP you can
use it free for any reason.

Re: Newbie zend license question

musicinmyhead wrote:

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Thank you so far, but some items somewhat not clear...
1. When I download latest 'PHP installment', am I also downloading the
   Zend engine inside it?
2. Is the Zend engine directly executing PHP commands or is it converted
   into something else that Zend then interprets?
3. If I write a standard PHP application like the dozens of wiki's out there
   in PHP, in what way am I to know
   if I stumbled and accidentally I'm building 'around the Zend engine'?
4. If I distribute a commercial application, then, because I'm
   downloading the Zend engine and shipping it commercially, is
   that going to force me to pay?

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Re: Newbie zend license question

1) Yes you are downloading the Zend engine inside it, as PHP cannot run
without the Zend engine (unless for some reason you've found a way to
do so).

2) Zend is a scripting engine, therefore it reads your PHP page,
processes it and then sends the appropriate data to your web-server for
output. Zend directly executes PHP commands.

3) If you're writing in PHP then you can't accidentally build "around
the Zend engine." That would be similar to saying that you were coding
in C++ and accidentally built "around your operating system," so it
doesn't really work in the context that you're referring to.

When building an application in PHP, you are building "around PHP," not
around the Zend engine. PHP is free and open-source, always. If the
wiki that you're developing is done with PHP you will not have to worry
about the Zend engine. The "only" time you have to worry about the Zend
license is if you're literally developing you're own version of PHP
from scratch for instance, using the Zend engine library directly, and
your intent is to sell / distribute that application commercially.

4) No, here's the exact text on that from the PHP license:
Q. The Zend license says I may not charge money for stuff I sell along
with Zend. Does that mean I cannot sell PHP scripts or web sites that I

A. No. Not at all. This clause only concerns software built around the
Zend scripting engine library, not scripts that PHP executes, using
that library. You are free to distribute PHP source code you write
freely or commercially, without any concern about the PHP or Zend
licenses. <b>You may also package PHP as a whole with your commercial
applications as much as you want.</b> You just can't build commercial
applications that use the Zend scripting engine library directly.

Basically, the only thing you need worry about when developing any
application using PHP is "Did I make it clear in my application that it
runs on PHP?" In other words, just make sure that you gave credit to
the PHP development team since you're using their software. You can
freely distribute and modify PHP for commercial or non-commercial
purposes, so long as it's clearly stated that it's PHP.

Re: Newbie zend license question

musicinmyhead wrote:

Thank you again, thats cleared up a lot of things including
whats meant by building around PHP and around Zend.

One or two weeny more clarifications...
Just imagining a confrontational situation where Zend is
taken over by M$ and want to shut it down...

1. Can the Zend library be revoked by the new owners leaving
PHP dead in the water?

2. If trivial bugs exists inside Zend, I assume PHP developers can
work around it without having to fix Zend?

3. If a new version of Zend is released by new owner, the PHP developers
can choose to ignore it if they don't trust it?

4. If Zend is suddenly withdrawn by new owners, can an independent
or an open source Zend be made with all the available
documentation on Zend?

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Re: Newbie zend license question

1) As far as I'm aware no. Since the Zend engine in it's current state
is open-source I believe that even if a company were to "buy out" Zend
so to speak, the current licenses would still apply to the product.

I would compare the situation to say, if someone had bought out Linux
for instance, would they be able to demand that everyone uninstall
whatever version of Linux that they currently have installed? It's
highly doubtful, and I'm pretty sure it's not possible.

2) Mostly yes, but sometimes no. It really just depends on the bug and
where or when it occurs when the Zend engine is processing. Usually
they can fix the problem, and that's when you'll see a new version (or
patch) of PHP released (i.e. 5.04, 5.05 etc..), to fix the current bugs
or improve performance.

3) Yes they can choose to ignore it. Since PHP has already packaged a
specific version of the Zend engine (which happens to be open-source)
along with PHP, if they like they can choose to ignore all future
versions of it for any reason they like.

4) I believe so yes, but don't trust my word on that as I'm not
entirely sure. I think that since the current Zend engine is
open-source (for non-commercial purposes) then anyone can offer it free
for download, and offer the documentation for it also.

I may have not specified this before, but Zend is already open-source.
The only thing is that they don't approve of commercial use of their
engine unless you've acquired the appropriate license for it. And since
they've made it open-source, anyone anywhere is free to distribute the
source non-commercially, or modify the source so long as they provide
the modifications in the form of a patch (separate from the source

And as a last note, you can view the license under which Zend is
distributed here:
It is know as the "QPL License" or "Q Public License."

Re: Newbie zend license question

musicinmyhead wrote:

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Thank you very very much.
This has cleared up everything as far as investing time
and energy in PHP over say M$ ASP.

I've just done my first script to create a table in MySQL
and I didn't have to pay!
Well... Ordeal by fire finding out MySQL library is disabled by default!

But its working and I'm really gonna enjoy this after getting
my fingers burnt investing time in M$ ASP and IIS pretentious crap.

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