# Схема: ButtonCallback

Source: <https://telegafirst.com/docs/schema-ec83e55f327a188963dabeed62f1ffec295a99faee332b9e3dcb5b934f477bd0>
Locale: ru
releaseGitSha: fc570c76ffc9cb87e2462d45b14f5c1b52fbaf0d
sourceContentDigest: 7fd1e53eb815f4cd747c8a5a8bc2c42ee34e2418f3a1872166540111ae8a29d7
Version: 2

# Схема: ButtonCallback

| Поле | Значение |
| - | - |
| properties.callback\_data.description | "An integration mechanism of an ExternalApp key: when the user taps the button, the value is delivered by the button.clicked webhook to the server of the app that sent the push, so the app must have been subscribed to the button.clicked webhook when it was provisioned, otherwise the button is refused with INVALID\_BUTTON\_CONFIG. Sent with any other credential (an OAuth grant or an M2M credential) a callback button is refused with INVALID\_BUTTON\_CONFIG. The platform prefixes it with ext:{app}:, and the prefixed value must fit 64 bytes. Answered only for a Telegram user: for a MAX or VK user a callback button is refused with INVALID\_BUTTON\_CONFIG — use a url button." |
| properties.callback\_data.maxLength | 64 |
| properties.callback\_data.type | "string" |
| properties.text.maxLength | 30 |
| properties.text.type | "string" |
| properties.type.enum | \["callback"] |
| properties.type.type | "string" |
| required | \["text","type","callback\_data"] |
| type | "object" |