Tender runs as a PWA and uses the Automerge crdt and sqlite via wasm. The app more or less runs entirely in your browser (works offline!), though our server proxies connections to pull in plaid/splitwise data.
Feature-wise, we're targeting folks who do want to manage their expenses but not have to do fine-grained budgeting. There's tools for tracking getting paid back and a splitwise integration as well. The app is desktop-centric right now, but we're working on getting a good mobile workflow together too.
Since everything is browser-based, it was actually quite easy to get a demo sandbox environment working. You can give it a quick spin here: https://demo.tender.run