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drop

Available in: Cloud, Self-Managed

Silently discards all messages without error or side effects.

The drop output is a utility component that drops messages from the pipeline. Unlike filtering or conditional processors that modify or route messages, drop consumes messages and does nothing with them. This is useful for:

  • Testing and debugging: Measure input throughput without output bottlenecks

  • Conditional workflows: Discard messages that don’t meet certain criteria

  • Dead letter queue patterns: Provide a final fallback when all other outputs fail

  • Development: Temporarily disable output while testing pipeline logic

Use this reference to:

  • Look up drop output syntax and configuration

  • Find examples of drop in conditional routing

  • Identify use cases for drop output in pipelines

outputs:
  label: ""
  drop: {}

Performance

The drop output has minimal overhead and immediately acknowledges messages. This makes it ideal for performance testing, as it removes output processing time from measurements.

Examples

Conditional filtering

Use drop with the switch output to conditionally discard messages:

output:
  switch:
    cases:
      - check: this.type == "error"
        output:
          label: error_sink
          kafka:
            addresses: ["kafka:9092"]
            topic: errors
      - check: this.type == "debug"
        output:
          label: drop_debug
          drop: {}  # Don't process debug messages in production
      - output:
          label: main_sink
          kafka:
            addresses: ["kafka:9092"]
            topic: events

Dead letter queue pattern

Use drop as a last resort in a fallback chain:

output:
  fallback:
    - kafka:
        addresses: ["kafka:9092"]
        topic: primary_topic
        max_in_flight: 1
    - kafka:
        addresses: ["kafka:9092"]
        topic: dlq_topic
    - drop: {}  # Last resort: drop if both outputs fail

Testing input throughput

Measure how fast your input can consume data without output bottlenecks:

input:
  kafka:
    addresses: ["kafka:9092"]
    topics: ["test"]
output:
  drop: {}  # Measure input consumption speed without output overhead

For more patterns on message routing, filtering, and when to use drop vs. other approaches, see the Message Routing Patterns cookbook.