Finance Architecture & Specs

The ledger is the mathematical foundation of Aeion Finance — every transaction must balance before it's allowed to post.

Core validation rule: the sum of all debit lines in a transaction must equal the sum of all credit lines. If they don't match, the whole transaction is rejected before anything touches the books — no partial posts, no "fix it later."

Immutability enforcement:

• No edit or delete operations are permitted on finalized ledger entries — this is enforced at the database level, not just in application code
• Corrections require a new reversing journal entry
• Every entry carries who created it, when, and an immutable sequence number
• The audit trail can't be retroactively altered — not by an admin, not by a bug, not by anyone

Atomic transactions: all journal entry postings execute inside a single database transaction. If any line fails validation, the entire batch rolls back — you never end up with half a journal entry sitting in your books.

Vision AI extracts structured financial data from a photographed or uploaded receipt.

Process:

1. Upload a receipt image (from mobile or desktop)
2. AI extraction validates the output against a strict schema before anything is accepted
3. Structured data comes back: merchant, date, total, tax, currency, suggested GL category, and line items

What you get back:

• Merchant / vendor name
• Date (normalized)
• Total amount paid, including tax
• Tax amount
• Currency
• Suggested GL category
• Line items (description, quantity, amount) where the receipt has them

Integration: extracted data flows directly into the accounts-payable workflow — upload a photo, and a bill is ready to review with the fields already filled in. Works equally well for a production department's on-set purchases as for routine office expenses.

Fallback: if AI extraction is unavailable, the pipeline surfaces an error rather than accepting an unverified receipt — nothing enters the books without either AI verification or a human's sign-off.

Bank connectivity runs through a standard OAuth flow, giving you read access to transactions without ever handling your bank password directly.

Connection flow:

1. You launch the bank-connect flow from the admin UI
2. You authenticate directly with your bank (or search + select it) in a secure, hosted window
3. Aeion receives a long-lived access credential in exchange for a one-time authorization code
4. That credential is encrypted (AES-256-GCM) before it's ever written to the database

Transaction sync:

• Transactions are pulled on connection and kept current via real-time webhook push
• Each transaction is mapped into Aeion's internal transaction record
• Account data includes name, mask, type, subtype, and available/current balances (tracked in cents for precision)