My own project. I wanted to merge, sign and redact contracts without handing them to iLovePDF or Smallpdf, so everything runs in your browser: no backend, the CSP blocks connections to other hosts, no analytics, no account. Redaction actually removes the text instead of covering it. Don’t want to trust the hosted copy? Self-host it with Docker or use the offline Windows app.
https://github.com/jurecki007/nyxiontech-tools https://tools.nyxiontech.com/
What about OmniTools? You can self host it with docker/podman, or use the website. I’m pretty sure all calculations are done on device and not sent away, but don’t trust me on that.