Account Type Architecture#

Sure models financial accounts using Rails' delegated_type pattern. The Account record is the single shared table for all accounts; it delegates to one of 9 accountable types, each backed by its own model and database table 1.

The canonical list of types is defined in the Accountable concern:

Depository | Investment | Crypto | Property | Vehicle | OtherAsset
CreditCard | Loan | OtherLiability

Classification: Assets vs. Liabilities#

Account carries a classification enum (asset / liability) 2, with corresponding assets and liabilities scopes 3. The value is determined by each accountable model's classification class method — a required contract enforced by the Accountable concern.

The favorable_direction helper 4 derives from classification: assets trend "up", liabilities trend "down".

The Accountable Concern#

app/models/concerns/accountable.rb is the shared interface all 9 types must implement:

• Required class methods: classification, icon, color 5
• SUBTYPES constant: defaults to {} 6; overridden per type to declare valid subtypes with short/long display labels
• subtype_label_for(subtype, format:) 7: resolves a subtype key to its display label via I18n, falling back to the SUBTYPES hash
• balance_money(family) 8: sums all active accounts of a given type, converting foreign currencies using ExchangeRate

The Account model delegates subtype to the accountable 9, with special handling for the case where subtype is assigned before the accountable record is built 10.

Accountable Types and Their Subtypes#

Depository — Asset#

app/models/depository.rb: Subtypes: checking (default), savings, hsa, cd, money_market 11.

CD/FD as term deposits: cd (Certificate of Deposit) is a Depository subtype. The Indian equivalent, FD (Fixed Deposit), is an Investment subtype (fd) with region: "in" 12 — both model term deposits but are routed to different primary types based on how Plaid categorizes them.

HSA receives tax_treatment: :tax_advantaged via TAX_ADVANTAGED_SUBTYPES 13 without touching the shared TaxTreatable concern.

Investment — Asset#

app/models/investment.rb: The most subtypes of any accountable — 50+ entries organized by region 14:

Each subtype carries a tax_treatment value (:taxable, :tax_deferred, :tax_exempt, :tax_advantaged) 15. The subtypes_grouped_for_select helper 16 uses the family's currency to surface the user's likely region first.

Loan — Liability#

app/models/loan.rb: Subtypes: mortgage, student, auto, home_equity, line_of_credit, business, other 17. Also calculates monthly_payment from term_months and interest_rate for fixed-rate loans 18.

Crypto — Asset#

app/models/crypto.rb: Subtypes: wallet and exchange 19.

Property — Asset#

app/models/property.rb: Subtypes include single_family_home, multi_family_home, condominium, townhouse, investment_property, second_home, apartment, plot, commercial, agri_land 20.

CreditCard — Liability#

app/models/credit_card.rb: Single subtype: credit_card 21.

Vehicle, OtherAsset, OtherLiability#

Vehicle (asset), OtherAsset (asset), OtherLiability (liability) — no SUBTYPES defined; they use the default empty hash from the Accountable concern 6.

Key Source Files#