# MediaTailor parameter character restrictions and URL-encoding
<a name="manifest-query-parameters-character-restrictions"></a>

AWS Elemental MediaTailor supports specific characters in manifest query parameters. You can use URL-encoding for special characters.

**Supported characters with URL-encoding**  
The following special characters are supported with URL-encoding:
+ period (.) = %2E
+ dash (-) = %2D
+ underscore (\_) = %5F
+ percent (%) = %25
+ tilde (\~) = %7E
+ forward slash (/) = %2F
+ asterisk (\*) = %2A
+ equals (=) = %3D
+ question (?) = %3F

**URL-encoding support**  
MediaTailor supports the percent (%) sign when you use it in URL-encoding (for example, hello%20world = hello world). You can use any URL-encoded characters, as long as they are valid URL-encodings according to the HTTP specification.

**Important**  
MediaTailor doesn't support double characters such as %%% or ==.

**Security considerations**  
MediaTailor implements the following security measures for parameter handling:

1. Input size limitations to prevent database bloat

1. Proper encoding and sanitization of user input

1. URL-encoding of input to prevent response corruption