# Схема: ButtonCallback

Source: <https://telegafirst.com/docs/schema-4fff85570d7119a3227c715880cd0f4b2179370507d0b324a126ca523588aa44>
Locale: ru
releaseGitSha: 0bb11ef116e17ec64c802d5476eaff442e53d252
sourceContentDigest: 9bf65c941453ef86002577424f144ae79e384f8a5c1b2e883275b990038586ec
Version: 6

# 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 MCP send\_notification tool carries url buttons only. 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" |