If you are playing the current, modern version of TiTS (which you likely are if you're playing on the Fenoxo website), this is the most relevant and recommended tool. Hosted on GitHub, the tits.js-save-editor is a static website designed specifically to edit the save files for the game's JavaScript version.
Depending on whether you are playing the older Flash version or the modern JavaScript (JS) version of the game, your choice of editor will differ: trials in tainted space save editor