# Why broker delivery is not financial truth

Canonical: https://stevenmoriasi.com/blog/broker-delivery-is-not-financial-truth
By [Steven Moriasi](https://www.linkedin.com/in/steven-moriasi/).
Source: https://github.com/steven-moriasi/mobility-finance-event-platform
Date: 2026-09-20

## Context

Once internal workers exist behind a BFF, the next confusion is treating a delivered message as a repayment. Message delivery and double-entry state are different facts. Reconciliation has to survive a broker outage without inventing money.

This note is the ledger side of [Mobility Finance Event Platform](https://github.com/steven-moriasi/mobility-finance-event-platform). The public-boundary decision is [why the BFF is the only public boundary](/blog/mobility-finance-event-platform).

## Decision

Double-entry repayment state is stored separately from broker delivery. Workers consume internal events; they do not become the accounts. Recovery is a command: `make recovery-drill` exercises a broker outage and the path back to a consistent ledger, not a replay that posts twice.

## What I rejected

Using the bus (or an in-memory queue) as the loan book, and marking a repayment posted because the broker said delivered. Delivery is transport. The posting is a ledger row with its own idempotency.

## Failure scenario

The broker is down. In-flight work is not silently posted. After the drill, duplicate delivery of the same event does not create a second repayment. In-memory persistence is an explicit current boundary, documented next to the recovery drill.

## Evidence

`make recovery-drill`, [recovery notes](https://github.com/steven-moriasi/mobility-finance-event-platform/blob/main/docs/recovery.md), and architecture that keeps domain services off the public network. Synthetic data only; no real lending, payment collection, or device control.

Inspect: [Repository](https://github.com/steven-moriasi/mobility-finance-event-platform) · [Recovery drill](https://github.com/steven-moriasi/mobility-finance-event-platform/blob/main/docs/recovery.md) · [Architecture](https://github.com/steven-moriasi/mobility-finance-event-platform/blob/main/docs/architecture.md)

_—by [Steven Moriasi](https://www.linkedin.com/in/steven-moriasi/)_