# Callbacks overview

Kycaid sends callbacks to notify your system about events related to verifications, documents, forms, and services. Each callback is delivered as an HTTP POST request to the `callback_url` you provide, with a JSON body describing the event.

## Common structure

Every callback includes a `type` field that identifies the event, for example `VERIFICATION_COMPLETED` or `DATABASE_SCREENING`. The rest of the payload depends on the callback type — see the individual pages in this section for the exact schema of each one.

## Available callbacks

| Callback | Sent when |
|  --- | --- |
| [Database screening](/callbacks/database-screening) | A match is found in a blacklist database during ongoing monitoring |
| [Document expired](/callbacks/document-expired) | A previously verified document reaches its expiration date |
| [Service result](/callbacks/service-result) | An asynchronous service request (for example, a crypto address or transaction check) completes |
| [Form URL expired](/callbacks/form-url-expired) | A generated form URL passes its expiration time |
| [Signed document](/callbacks/signed-documents) | A document is signed through Qualified Electronic Signature (QES) |
| [Transaction screening](/callbacks/transaction-screening-completed) | A transaction monitoring rule finishes evaluating a transaction |
| [UA Diia auth completed](/callbacks/ua-diia-auth-completed) | A Diia authentication request completes |
| [Verification completed](/callbacks/verification-completed) | A verification reaches a final status |
| [Verification status changed](/callbacks/verification-status-changed) | A verification's status changes |


## Response and retry policy

Your server must respond with an HTTP status code in the `2xx` range within `10 seconds` to acknowledge a callback. If Kycaid does not receive such a response in time, the callback is retried at the following intervals: `1 minute`, `5 minutes`, `10 minutes`, `30 minutes`, `1 hour`, `3 hours`, `6 hours`, `12 hours`, `24 hours`.

## Verifying callback authenticity

To confirm that a callback genuinely came from Kycaid and wasn't sent or altered by a third party, see [Callback integrity verification](/callbacks/callback-integrity-verification).