Use interpolation in multi-line strings

Author: mumian

articles/azure-resource-manager/bicep/data-types.md

@@ -355,14 +355,11 @@ var storageName = 'storage${uniqueString(resourceGroup().id)}'
 
 ### Multi-line strings
 
-In Bicep, multi-line strings are defined between three single quotation marks (`'''`) followed optionally by a newline (the opening sequence) and three single quotation marks (`'''` is the closing sequence). Characters that are entered between the opening and closing sequence are read verbatim. Escaping isn't necessary or possible.
+## Multi-line strings
 
-> [!NOTE]
-> The Bicep parser reads every character as it is. Depending on the line endings of your Bicep file, newlines are interpreted as either `\r\n` or `\n`.
->
-> Interpolation isn't currently supported in multi-line strings. Because of this limitation, you might need to use the [`concat`](./bicep-functions-string.md#concat) function instead of using [interpolation](#strings).
->
-> Multi-line strings that contain `'''` aren't supported.
+You can define a multi-line string by enclosing it in three single quotation marks (`'''`). The string content is preserved exactly as written, so escape characters are not required. The delimiter `'''` cannot appear within the string.
+
+The string may begin immediately after the opening delimiter or on the following line. In both cases, the resulting value does not include a leading newline. Line breaks are interpreted as `\r\n` or `\n`, depending on the line-ending format of the Bicep file.
 
 ```bicep
 // evaluates to "hello!"
@@ -396,6 +393,21 @@ var myVar6 = '''interpolation
 is ${blocked}'''
 ```
 
+With Bicep CLI version 0.X.X or higher, string interpolation is supported. An optional `$` prefix can be added before the opening delimiter to enable string interpolation using standard Bicep `${...}` syntax. If you need to include ${...} as a literal value without escaping, you can control interpolation by repeating the `$` prefix. Interpolation is only performed when the number of `$` characters preceding `${...}` matches the number of `$` characters used in the opening delimiter.
+
+```bicep
+// evaluates to "this is a test"
+var interpolated = 'a test'
+var myVar7 = $'''
+this is ${interpolated}'''
+
+// evaluates to "this is a testthis is not ${interpolated}"
+var interpolated = 'a test'
+var myVar8 = $$'''
+this is $${interpolated}
+this is not ${interpolated}'''
+```
+
 ### String-related operators
 
 - See [Comparison operators](./operators-comparison.md).

articles/azure-resource-manager/bicep/file.md

@@ -3,7 +3,7 @@ title: Bicep file structure and syntax
 description: Understand how to use declarative syntax to understand the structure and properties of Bicep files.
 ms.topic: article
 ms.custom: devx-track-bicep
-ms.date: 07/25/2025
+ms.date: 01/13/2026
 ---
 
 # Bicep file structure and syntax
@@ -412,32 +412,6 @@ The following example shows a multiline comment.
 param existingKeyVaultName string
 ```
 
-## Multi-line strings
-
-You can break a string into multiple lines. Use three single quotation marks `'''` to start and end the multi-line string.
-
-Characters within the multi-line string are handled as is. Escape characters are unnecessary. You can't include `'''` in the multi-line string. String interpolation isn't currently supported.
-
-You can start your string right after the opening `'''`, or include a new line. In either case, the resulting string doesn't include a new line. Depending on the line endings in your Bicep file, new lines are interpreted as `\r\n` or `\n`.
-
-The following example shows a multi-line string.
-
-```bicep
-var stringVar = '''
-this is multi-line
-  string with formatting
-  preserved.
-'''
-```
-
-The preceding example is equivalent to the following JSON:
-
-```json
-"variables": {
-  "stringVar": "this is multi-line\r\n  string with formatting\r\n  preserved.\r\n"
-}
-```
-
 ## Multiple-line declarations
 
 You can now use multiple lines in function, array, and object declarations. This feature requires [Bicep CLI version 0.7.X or higher](./install.md).