What I wanted to say was: "PDF processing is something where I wouldn't want to rely on an online API over something local. And it's also something where I wouldn't want to rely on a small commercial company over an open source project".
I once worked for a software company where non-tech clients would have custom-made software developed for their exclusive use. Half the projects we did were "We're relying for one of our business functions on this software that we bought from this company that's now out of business. We need you to reimplement it from scratch, because we need a tiny change."
To me it makes sense to buy this functionality instead of building it yourself, the upfront cost involved with building it yourself will likely be much higher even if you manage to chain together a bunch of open source tools.
I once worked for a software company where non-tech clients would have custom-made software developed for their exclusive use. Half the projects we did were "We're relying for one of our business functions on this software that we bought from this company that's now out of business. We need you to reimplement it from scratch, because we need a tiny change."