# Character Encoding in Advar Responses
When special characters are used in creative field values, the Adhese ad response (advars) does not always return them as-is. This page describes the current encoding behavior so integrators can correctly process the `ad.tag` property and display these values.
### Character processed without change
`! @ # $ % ^ * ( ) : ; | ? / , . ~ ``
### Always entity-encoded
Regardless of account configuration, the following characters are always encoded:
| character | name | encoded as |
|---|
| `&` | ampersand | `&` |
| `"` | double quote | `"` |
| example: | encoding |
|---|
| "Abc" K&L | `"Abc" K&L` |
### Single quote: controlled by the `escapeAdvarStrategy` setting
How a single quote (`'`) is encoded depends on the account's `escapeAdvarStrategy` configuration property. This property exists because a single, universal escaping approach doesn't work for every delivery format:
- the HTML entity `’` only decodes correctly in HTML contexts
- in native or JSON tags it would otherwise show up to the end user as literal entity text.
| value of
`escapeAdvarStrategy`
| behavior | example:
`O'Brien` |
|---|
| `raw` | No escaping — the quote is passed through as-is | `O'Brien` |
| `html` | HTML-entity escaping | `O’Brien` |
| `accent` | The quote is replaced with an acute accent (`´`) — a visual substitution, not a true escape | `O´Brien` |
**Fallback:** if `escapeAdvarStrategy` is unset, blank, or set to an unrecognized value, the account falls back to its legacy `escapeAdvarParams` boolean: `false` behaves like `raw`, and `true` (the default) behaves like `html`.
Accounts that haven't set `escapeAdvarStrategy` are unaffected and continue to behave exactly as before.
Integrators should decode a value according to the account's configured strategy before displaying it. For an account using `html` (the default), a value containing `T&T` is returned as `T&T` and should be decoded back to `T&T`; a value containing `O'Brien` is returned as `O’Brien` and should be decoded back to `O'Brien`.
### Unsupported characters
The following characters currently cannot be saved in a creative field:
| character | name | behavior |
|---|
| `\` | backslash | Results in a malformed value in the ad response |
| `<` | less than sign | Not accepted when saving the creative |
| `>` | more than sign | Not accepted when saving the creative |
Don't use these characters in field values!
### Note
Encoding behavior is subject to change; this page will be updated if the rules above change.