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name: ledger description: Financial ledger - transactions, audit trails. Use when tracking money.

Ledger Guideline

Tech Stack

• Database: Neon (Postgres)
• ORM: Drizzle

Non-Negotiables

• Balances must be immutable ledger (append-only), not mutable fields
• No floating-point for money (use deterministic precision)
• All financial mutations must be idempotent
• Every balance must be provable by replaying the ledger

Context

Ledger handles financial integrity — transaction history, balance correctness, audit trail. Payment processing lives in billing, pricing strategy lives in pricing.

A bug that creates or destroys money is a serious incident. This must be bulletproof.

Driving Questions

• Does a balance/credits system exist, and is it implemented correctly?
• Where could money be created or destroyed by a bug?
• What happens during concurrent transactions?
• How would we detect if balances drifted from reality?
• Can we prove every balance by replaying the ledger?