I've found most spam comes from bots operating from certain countries. Filtering traffic by IP address will stop a lot of spammy traffic. I've used a combination of GeoIP and IP address catagorization to limit the impact of bots on my side-projects.
I'm a data janitor who prefers writing boring software using boring technologies. I'm particularly good at turning piles of spreadsheets into data-driven dashboards.
If print friendly reports are a requirement, I'd go with QuickChart (https://quickchart.io.)
Static charts similar to chart.js, but without all the javascript. I've found static charts are much easier to work with once print CSS layout becomes a requirement.
Generating PDF's from HTML is a huge PITA. I really like what you've done.
re: "is it clear upon viewing the landing page what the product is about?"
Yes. I think your landing page copy reads well, but could use a bit of polish. Emphasis how well PdfApi solves common margin and background rendering issues compared to other alternatives.
re: "are there any questions that you have that are not answered on the page"
I'm not sure you need to answer all of a users questions, but considering you are targeting startups and developers, I'd focus on building out your API documentation.
re: "would this product provide value to you if your startup needed to generate PDFs"
Potentially, but considering your audience (developers/startups) I suspect most of us would tackle the issue locally with a Chrome headless setup.
re: "what would you use instead"
I've used the following to generate PDF's from HTML:
* Chrome Headless
* WKHTMLtoPDF
This is good work. I like what you've done. Build out strong API documentation with multiple code snippets and examples to improve your developer marketing.
F.I.S.H. is a mashup of several data sources to help me explore my adopted state of Washington.
I'm using data provided by the United States Geological Survey, TrailAPI.com, The Beer Mapping Project, ReserveAmerica, Mapbox and OpenStreetMap to build an application to map a few of my favorite things: fishing, camping, hiking, mountain biking, and beer.
Thank you for all the effort you've put into this project. Love the clean design and how you've used affiliate links and merchandising to monetize the site. A+ work.