dynamic_to_json

Use the dynamic_to_json function to convert a dynamic-typed value—such as a property bag, array, or nested JSON structure—into a canonical JSON string representation. This is helpful when you want to serialize dynamic data for storage, transmission, or further string manipulation.

You typically use dynamic_to_json when working with semi-structured data that you need to convert to a string format, especially when exporting data or passing dynamic values to functions that expect string input.

Usage

Syntax

dynamic_to_json(dynamic)

Parameters

Returns

Returns a canonical JSON string representation of the input according to the following rules:

• If the input is a scalar value of type other than dynamic, the output is the result of applying tostring() to that value.
• If the input is an array of values, the output is composed of the characters [, ,, and ] interspersed with the canonical representation of each array element.
• If the input is a property bag, the output is composed of the characters {, ,, and } interspersed with colon (:)-delimited name/value pairs of the properties. The pairs are sorted by the names, and the values are in the canonical representation described here.

Use case examples

['sample-http-logs']
| extend metadata = bag_pack('method', method, 'status', status, 'duration', req_duration_ms)
| extend json_metadata = dynamic_to_json(metadata)
| project _time, ['uri'], json_metadata

['otel-demo-traces']
| extend trace_attributes = bag_pack('service', ['service.name'], 'kind', ['kind'], 'status', ['status_code'])
| extend json_attributes = dynamic_to_json(trace_attributes)
| project _time, ['trace_id'], json_attributes

['sample-http-logs']
| extend security_event = bag_pack('timestamp', _time, 'status', ['status'], 'uri', ['uri'], 'location', strcat(['geo.city'], ', ', ['geo.country']))
| extend event_json = dynamic_to_json(security_event)
| project _time, event_json

List of related functions

• todynamic: Converts a JSON string to a dynamic value. Use todynamic to parse JSON strings, and dynamic_to_json to serialize dynamic values back to strings.
• tostring: Converts any scalar value to a string. Use tostring for simple scalar conversions, and dynamic_to_json when you need canonical JSON formatting for dynamic values.
• parse_json: Parses a JSON string into a dynamic value. Use parse_json to create dynamic values from JSON strings, and dynamic_to_json to convert them back.
• toarray: Converts a dynamic value to an array. Use toarray when you need array operations, and dynamic_to_json when you need string output.

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