Data contract for analytics eventing

# producer: orders service def emit_order_event(order): kafka.send('orders', { 'order_id': order.id, 'status': order.status, # free-form string, renamed often 'amt': order.total, # sometimes dollars, sometimes cents 'ts': time.time()}) # no schema, no version # consumers: analytics, billing, support dashboards Consumers frequently break when the producer changes fields or units. What is the correct architectural fix?