base64ToString — Power Automate (WDL) function reference

Decode base64 to text.

Syntax

wdl

base64ToString(value)

wdl

base64ToString(variables('enc'))

→ "hello"

Common for decoding a base64-encoded JSON payload from a webhook.

wdl

json(base64ToString(triggerBody()?['data']))

→ A parsed object

wdl

base64ToString(items('Apply_to_each')?['contentBytes'])

→ The decoded text content

Assumes UTF-8 text underneath the base64 — decoding base64 that actually represents binary content (e.g. an image) produces unusable garbled text, not an error.
Malformed base64 input (wrong padding/invalid characters) throws an InvalidTemplate error rather than returning a partial result.

From Type conversion