If I were building this, I wouldn't do that. I would build one piece, as a well-documented Pythonic (not in Python; just in coding / documentation style) libra

If I were building this, I wouldn't do that. I would build one piece, as a well-documented Pythonic (not in Python; just in coding / documentation style) library. The reason this is impossible is the monolithic design of these things. There are good reasons for it -- the pieces interrelate -- but I think it's possible to break it up (with a lot of work). For example: - A clean, documented JavaScript engine would be a good start. - Python-style, independent, isolated JavaScript libraries would help (usable serverside or clientside where possible) - An independent rendering engine would be nice -- again, documented and independent of the above - Network libraries - HTML / XML / CSS parsing libraries ... etc. If this were in place, code could be interchangeable between serverside and clientside much more than today (and usable in other places, such as using JS as a scripting language in other systems). Test cases for rendering (or even just making a screenshot) wouldn't need the whole browser. You would import and call into the rendering engine to make a .png without selenium. Making a new web browser would involve mostly glue code and OS-specific code.