Miyo
Solo · 2026Finance for couples merging money
- Account privacy
- 3 statesPrivate, shared, or hidden
- CSV formats
- 4 banksImported with duplicate protection
- Privacy boundary
- Server-sideEnforced beyond the interface
Overview
A finance app for couples merging their money for the first time — every account has its own privacy dial, so saying yes to “ours” never costs you “mine.”
What I built
- →Per-account privacy states—private, shared, or hidden—enforced before data reaches the interface
- →Two-member households with expiring invites, ownership transfer, and partner views
- →Plaid sync with encrypted tokens, cursor-based updates, and webhook deduplication
- →CSV import for four banks with duplicate and formula-injection protection
- →Debt payoff comparisons across avalanche, snowball, and hybrid strategies
Key product decision
Treat privacy as a server-side data boundary—not a visibility toggle—so a partner can never retrieve an account the interface says is hidden.
Case study notes
Context
Couples merging money face an all-or-nothing choice — fully combine accounts or stay siloed — and neither respects that some things are shared and some are still “mine.”
Implementation
I started with the household and account-permission model, enforced privacy on the server, then added bank sync, CSV import, budgeting, debt planning, and net-worth views around that boundary.
Current state
The product is live at joinmiyo.com for evaluation. Public beta still depends on completing the bank-sync lifecycle, onboarding, and operational monitoring.
Roadmap
In progress- Complete and monitor the real-bank Plaid Transactions lifecycle
- Deliver partner invites and guided household onboarding
- Add operations views for sync, webhook, billing, and deletion health
Source is private — want a walkthrough or a deeper look? Email me.