Home Assistant Integration — bidirectional, sensors + services + notifications (vibe coded, feedback welcome!)

[ZenoBell]

Hi everyone! Ex-Splitwise user here, been running SplitPro for a while and love it ❤️

I built a full Home Assistant integration for SplitPro and wanted to share it with the community.

⚠️ Disclaimer first: This was fully vibe coded with AI assistance. It works great for my use case but there are likely bugs, edge cases, and probably security issues I haven't caught. I'm running it exclusively on my local LAN with no exposure to the internet so I'm personally fine with that but please keep this in mind before deploying it in a more exposed setup. Code review, improvements, and bug reports are very welcome!

What it does:

Sensors — total balance, you owe, you are owed, per-friend balances, per-group balances, last expense, recent expense count
Services — add and delete expenses directly from HA (voice assistant, dashboard buttons, automations)
Events — fires splitpro_expense_added automatically when a new expense is detected, triggering native HA notifications on your phone
Multi-user — each household member adds their own integration entry scoped to their email
Per-currency breakdown — each balance includes a currencies array for multi-currency setups

How it works:
Two parts:

5 TypeScript files added to src/pages/api/ha/ and src/lib/ — REST endpoints secured with a HA_API_KEY env variable. Reads directly from SplitPro's internal BalanceView Prisma model (the same data source the UI uses) so numbers match exactly what the app shows. Amounts are converted from BigInt minor units using ÷100 for 2-decimal currencies (EUR/USD), mirroring SplitPro's own toUIString() function.

9 Python files — a standard HA custom component (HACS-ready structure) with config flow UI, DataUpdateCoordinator, and full service definitions.

Tested on: v2.1.0, Home Assistant 2025+
Repo: https://github.com/ZenoBell/splitpro-ha the home-assistant/ folder has the HA component, src/pages/api/ha/ has the API endpoints.

Questions for the maintainers:

Would you be open to merging the API endpoints into main?
Should the HA component live as a separate repo (e.g. oss-apps/splitpro-ha) for HACS submission?
Any feedback on the API design or the HA_API_KEY auth approach?

If anyone wants to review the code, clean it up, or improve it, please go ahead, contributions very welcome! 🙏