I am working on a project to view pdf files online and merge it into single pdf file. For that, I don't know which programming language and tool is best for it. Kindly assist me in this issue. Personally i know PHP very well. So if you know tools in PHP, kindly tell me about it.

To me this is the question about the painter or sculpter and the brush or chisel. There is more to your skills that the tools you use.

To merge a PDF online you have a lot of code before you can consider the actual PDF Merge step. Did you get to the point you have the web site up to upload, download and more?

This is a very large project you are taking on. Figure a month or more of many steps and processes to complete. Why I note this is once in a while a person new to such work thinks it's some plugin or "if I choose the right language" it will be easy.

Easy would be to copy a prior site or google for code and slam it together (if you are good at slamming it togther.) My view is you have a big project ahead of you and PHP isn't a bad choice.

Thanks for your help. Do you know any website which can share its code with their users regarding online PDF viewer (opensource)?

Yes but it only help in to view pdf files but not merge it into single pdf file. sorry it did not solve my problem. Any other idea please???

@hamxamuradkhanh. You don't have a problem. You have a series of problems to solve, I noted above that you have a lot of actions to pull this together and this is why I wrote I worry you think there is one repository or tool that will answer all the problems.

In other words, you have a collection of tools, now you get to code and bring it all together.

I can't wait till you discover what happens on protected or otherwise non-coopertative PDFs.

I just want to render two pdf files online and merge into single pdf....For that, it require simple page code from pdf API. Do you know any API for it or should I try any other plateform? Thank you!

Wow! Downvoting a post, because it's not the answer you're after. Have some respect, sir! Anyway... I've got a good answer for you. Hire a developer!!!

If you want to view & merge them online then The first page of a Google search will give you about a dozen options, all free.

If you really mean offline, the I found this which you can execute via the command line after 20-30 seconds of Googling.

Did you bother to do even the simplest research before posting?

commented: Seek and you shall find a +1. +15
commented: Thank you kind sir +9

Sorry for any disrespect and thank you for your good help. I love this platform very much. Thank you Dani.