That's all available, fairly easily. At the federal level it's at congress.gov, including redlines for (some) amendments and versions. To be fair not every sing

That's all available, fairly easily. At the federal level it's at congress.gov, including redlines for (some) amendments and versions. To be fair not every single amendment vote is available, but that's a quirk of how the legislative process works. At the federal level, the US has a great bulk api from GPO/FDSys, including full bill text in plain, pdf, and XML. At the state level Openstates.org does it, including with an API. A lot of us in the space have mess with various "git diff" type solutions, but unfortunately the way bill text changes doesn't lend itself to this.