I need a software that can fill online pdf forms, without downloading them. Evince does fill forms but only offline, and adobe reader works with firefox online but it is not Open source.

I am looking for a alternative software that is open source and can fill pdf forms online.

Note that unlike Is there any useful software for filling out pdf-forms other than Adobe Reader? and Is there software that can fill PDF forms? question, I am specifically mentioning online forms. Also, I use Firefox mostly, but I don't have any problem in using any other browser.

2 Answers 2


No matter what you do, if you have a PDF form, and you want to fill it out, it will be downloaded in any case; otherwise, PDF would have to be interpreted and presented to the user on the server (this is, in fact, the case if the LiveCycle Forms Server is used on server side, and it would serve HTML5 (nowadays) if you access it via a web browser.

So, the answer is no, there is none (but I will stand corrected if there is). If you insist on filling the form within a web browser, you better stay with Adobe Reader and the Firefox plug-in. You have the best possible functionality, and you will not have problems with smart forms.


Firefox's mozilla/pdf.js now supports XFA forms. It would be available in Firefox 91 onwards.

If you want to use it right now,

  1. Download the latest Firefox Nightly appimage.
  2. Open about:config and set pdfjs.enableXfa preference to true.

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