Grafana Alloy is the new name for our distribution of the OTel collector. Grafana Agent has been deprecated and is in Long-Term Support (LTS) through October 31, 2025. Grafana Agent will reach an End-of-Life (EOL) on November 1, 2025. Read more about why we recommend migrating to Grafana Alloy.
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The json_decode function decodes a string representing JSON into a River value. json_decode fails if the string argument provided cannot be parsed as JSON.

A common use case of json_decode is to decode the output of a local.file component to a River value.

Remember to escape double quotes when passing JSON string literals to json_decode.

For example, the JSON value {"key": "value"} is properly represented by the string "{\"key\": \"value\"}".


> json_decode("15")

> json_decode("[1, 2, 3]")
[1, 2, 3]

> json_decode("null")

> json_decode("{\"key\": \"value\"}")
  key = "value",

> json_decode(local.file.some_file.content)
"Hello, world!"