# Attestation Types

> Learn about different attestation types supported by FDC.

> For the complete documentation index, see [llms.txt](/llms.txt). Markdown versions of documentation pages are available by appending `.md` to the page URL.

Source: https://dev.flare.network/fdc/attestation-types

**FDC Attestations** provide cryptographic proofs for data originating outside Flare's EVM state. They enable smart contracts to verify external data trustlessly. For example, FDC attestations can validate:

-   **Non-Payment Verification:** Confirm whether a payment **has not been made** on a UTXO chains like Bitcoin or Dogecoin.
-   **Event Log Authentication:** Verify event logs generated by transactions on EVM-compatible blockchains.

FDC currently supports the following attestation types:

## General attestation types

[

## Web2Json

Data retrieval from Web2 JSON APIs with JQ transformations.

](/fdc/attestation-types/web2-json)

[

## EVMTransaction

Information about an EVM transaction including events.

](/fdc/attestation-types/evm-transaction)

[

## Payment

Information about native token payments on an external chain.

](/fdc/attestation-types/payment)

[

## AddressValidity

Validates if a string is a legitimate external blockchain address.

](/fdc/attestation-types/address-validity)

[

## BalanceDecreasingTransaction

Detects a transaction decreasing the balance of an address.

](/fdc/attestation-types/balance-decreasing-transaction)

[

## ConfirmedBlockHeightExists

Assertion whether a specified block number is confirmed.

](/fdc/attestation-types/confirmed-block-height-exists)

[

## ReferencedPaymentNonexistence

Payment due by the agreed deadline has not been made.

](/fdc/attestation-types/referenced-payment-nonexistence)

## XRPL specific attestation types

[

## XRPPayment

Information about an XRP Ledger payment, including memo data and destination tag.

](/fdc/attestation-types/xrp-payment)

[

## XRPPaymentNonexistence

An XRP payment matching memo data and/or destination tag was not made by the deadline.

](/fdc/attestation-types/xrp-payment-nonexistence)