JSON

The JSON codec converts between line-delimited JSON byte payloads and columnar Arrow RecordBatches. Decoding uses Arrow's schema inference to map JSON objects to columns; encoding writes each row as one JSON object separated by newlines. It is the most common codec for attaching to inputs that emit JSON (Kafka, Redis, HTTP, etc.).

Configuration

Field	Type	Required	Default	Description
type	string	yes	—	Fixed value "json"
pretty	boolean	no	false	Metadata declaration field; the encoder currently always outputs newline-delimited form — whether this takes effect is governed by runtime behavior

The build implementation of this codec does not parse additional fields, so the configuration object can be omitted (i.e. codec: { type: json }). pretty is only declared in the component metadata schema.

Examples

input:
  type: kafka
  brokers:
    - localhost:9092
  topics:
    - events
  consumer_group: arkflow
  codec:
    type: json

output:
  type: stdout
  codec:
    type: json

Notes

• On decode, multiple byte payloads are concatenated with \n and handed to the Arrow JSON reader in a single pass for schema inference; field types must be consistent within a batch, otherwise inference errors may occur.
• Encoded output is newline-delimited JSON (one object per line), convenient for downstream line-by-line parsing.
• This codec implements both Encoder and Decoder, so it can be reused on both the input (decode) and output (encode) sides.