# ADR-003: Broadway for Velocity Pipeline

Status: Accepted | Date: 2026-05-21

## Context
After each transaction, velocity counters for 8+ entity dimensions must update.
Options: synchronous update (blocks response), direct Redis calls in Task, Broadway.

## Decision
Broadway consumer pipeline fed by Phoenix.PubSub fire-and-forget events.

## Justification
- Synchronous: adds 10–50ms to response time. Violates latency SLA.
- Raw Task: no backpressure, no fault tolerance, no dead-letter handling.
- Broadway: built-in concurrency, backpressure, retry, telemetry. Already in infra_queue.
  Pattern is identical to existing FilePipeline — reuse the same infrastructure.

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