> For the complete documentation index, see [llms.txt](https://docs.sign.global/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.sign.global/for-builders/index-1/npm-sdk/usage/attestations.md).

# Attestations

## Types

### Attestation (Onchain)

| Name                 | Type                               | Description                                                                                                                    |
| -------------------- | ---------------------------------- | ------------------------------------------------------------------------------------------------------------------------------ |
| schemaId             | `string`                           | Schema ID for this attestation.                                                                                                |
| linkedAttestationId? | `string`, `null`                   | The ID of the attestation that this attestation references.                                                                    |
| validUntil?          | `number`                           | Timestamp that this attestation is valid until.                                                                                |
| revoked?             | `boolean`, `null`                  | Whether or not this attestation is revoked.                                                                                    |
| recipients?          | `string[]`                         | List of recipient addresses.                                                                                                   |
| indexingValue        | `string`                           | The indexing value of this attestation. Can be used for filtering while querying using the indexing service.                   |
| attester?            | `address`                          | The attester's address.                                                                                                        |
| attestTimestamp?     | `number`                           | Timestamp that the attestation was created.                                                                                    |
| revokeTimestamp?     | `number`                           | Timestamp that the attestation was revoked.                                                                                    |
| dataLocation?        | `DataLocationOnchain`              | Where `Attestation.data` is stored. See `DataLocation.DataLocation`.                                                           |
| data                 | `{ [key: string]: any }`, `string` | If `dataLocation` is `ONCHAIN`, `data` is the data object. Otherwise, data is a `string` of the CID from the storage provider. |

### Attestation (Offchain)

| Name                 | Type                     | Description                                                                                                  |
| -------------------- | ------------------------ | ------------------------------------------------------------------------------------------------------------ |
| schemaId             | `string`                 | Schema ID for this attestation.                                                                              |
| linkedAttestationId? | `string`, `null`         | The ID of the attestation that this attestation references.                                                  |
| validUntil?          | `number`                 | Timestamp that this attestation is valid until.                                                              |
| revoked?             | `boolean`, `null`        | Whether or not this attestation is revoked.                                                                  |
| recipients?          | `string[]`               | List of recipient addresses.                                                                                 |
| indexingValue        | `string`                 | The indexing value of this attestation. Can be used for filtering while querying using the indexing service. |
| attester?            | `address`                | The attester's address.                                                                                      |
| dataLocation?        | `DataLocationOffchain`   | Where `Attestation.data` is stored. See `DataLocation.DataLocation`.                                         |
| data                 | `{ [key: string]: any }` | The data object to be stored with this attestation.                                                          |

## Creating Attestations

{% hint style="warning" %}
NOTE: You must provide an API key when initializing your SignClient to create offchain attestations. You can generate a key [here](https://developer.sign.global/). For more information, see [Installation](/for-builders/index-1/npm-sdk/installation.md).
{% endhint %}

### Creating an Attestation

```ts
async function createAttestation(
  attestation: Attestation,
  options?: CreateAttestationOnChainOptions
): Promise<AttestationResult>;
```

#### Parameters

| Name        | Type                              | Description                          |
| ----------- | --------------------------------- | ------------------------------------ |
| attestation | `Attestation`                     | An attestation object.               |
| options?    | `CreateAttestationOnChainOptions` | Options for creating an attestation. |

#### CreateAttestationOnChainOptions

| Name                   | Type                                | Description                                                                                          |
| ---------------------- | ----------------------------------- | ---------------------------------------------------------------------------------------------------- |
| resolverFeesETH?       | `BigInt`                            | ETH fees to be sent to the schema hook, in wei.                                                      |
| delegationSignature?   | `string`                            | The attester's delegate signature when creating an attestation on their behalf.                      |
| getTxHash?             | ``(txHash: `0x${string}`) => void`` | An optional callback that immediately returns the transaction hash.                                  |
| recipientEncodingType? | `RecipientEncodingType`             | Defines the attestation's recipient encoding type as either an address or string.                    |
| extraData?             | `0x${string}`                       | Extra data that is passed to the schema hook. This data is not stored by the Sign Protocol contract. |

#### Example

```typescript
const res = await client.createAttestation({
  schemaId: "0x3e",
  data: { name: "a" },
  indexingValue: "xxx",
});
```

### Delegating On-chain Attestation via ECDSA

```ts
async function delegateSignAttestation(
  attestation: Attestation,
  options: DelegateSignAttestationOptions
): Promise<AttestationDelegationSignature>;
```

#### Parameters

| Name        | Type                             | Description                                 |
| ----------- | -------------------------------- | ------------------------------------------- |
| attestation | `Attestation`                    | An attestation object.                      |
| options     | `DelegateSignAttestationOptions` | Options for delegate attestation signature. |

#### DelegateSignAttestationOptions

| Name                   | Type                    | Description                                                                                                                    |
| ---------------------- | ----------------------- | ------------------------------------------------------------------------------------------------------------------------------ |
| chain                  | `EvmChains`             | The EVM chain we are targeting.                                                                                                |
| delegationAccount?     | `PrivateKeyAccount`     | The signer account that signs the message. See `viem/accounts`. If this is null, a signer from `window.ethereum` will be used. |
| recipientEncodingType? | `RecipientEncodingType` | Defines the attestation's recipient encoding type as either an address or string.                                              |
| rpcUrl?                | `string`                | Optional RPC URL.                                                                                                              |
| walletClient?          | `WalletClient`          | Optional `WalletClient` from viem to use for transactions.                                                                     |

#### Example

```typescript
const { privateKeyToAccount } = require("viem/accounts");
const delegationPrivateKey = "0x...";
const delegationResult = await delegateSignAttestation(
  { schemaId: "0x3e", data: { name: "a" }, indexingValue: "xxx" },
  {
    chain: EvmChains.baseSepolia,
    delegationAccount: privateKeyToAccount(delegationPrivateKey),
  }
);
const res = await client.createAttestation(delegationResult.attestation, {
  delegationSignature: delegationResult.delegationSignature,
});
```

### Retrieving an Attestation

```ts
async function getAttestation(attestationId: string): Promise<Attestation>;
```

#### Parameters

| Name          | Type     | Description                                          |
| ------------- | -------- | ---------------------------------------------------- |
| attestationId | `string` | The ID of the attestation we are trying to retrieve. |

#### Example

```typescript
const res = await client.getAttestation("0x44");
```

## Revoking Attestations

### Revoke an Attestation

```ts
async function revokeAttestation(
  attestationId: string,
  options?: RevokeAttestationOptions
): Promise<RevokeAttestationResult>;
```

#### Parameters

<table><thead><tr><th width="219">Name</th><th>Type</th><th>Description</th></tr></thead><tbody><tr><td>attestationId</td><td><code>string</code></td><td>The ID of the attestation we are revoking.</td></tr><tr><td>options?</td><td><code>RevokeAttestationOptions</code></td><td>Options for revoking an attestation.</td></tr></tbody></table>

#### RevokeAttestationOptions

<table><thead><tr><th width="219">Name</th><th>Type</th><th>Description</th></tr></thead><tbody><tr><td>reason?</td><td><code>string</code></td><td>Reason for the revocation.</td></tr><tr><td>delegateSignature?</td><td><code>string</code></td><td>The user's delegate signature when revoking an attestation on their behalf.</td></tr><tr><td>getTxHash?</td><td><code>(txHash: `0x${string}`) => void</code></td><td>An optional callback that immediately returns the transaction hash.</td></tr></tbody></table>

#### Example

```typescript
const res = await client.revokeAttestation("0x44");
```

### Delegating On-chain Revocation via ECDSA

```ts
async function delegateSignRevokeAttestation(
  attestationId: string,
  options: {
    chain: EvmChains;
    delegationAccount?: PrivateKeyAccount;
    reason?: string;
  }
): Promise<RevokeDelegationSignature>;
```

#### Parameters

| Name          | Type                                   | Description                                   |
| ------------- | -------------------------------------- | --------------------------------------------- |
| attestationId | `string`                               | The ID of the attestation we are revoking.    |
| options       | `DelegateSignRevokeAttestationOptions` | Options for delegate revoking an attestation. |

#### DelegateSignRevokeAttestationOptions

| Name               | Type                | Description                                                                                                                    |
| ------------------ | ------------------- | ------------------------------------------------------------------------------------------------------------------------------ |
| chain              | `EvmChains`         | The EVM chain we are targeting.                                                                                                |
| delegationAccount? | `PrivateKeyAccount` | The signer account that signs the message. See `viem/accounts`. If this is null, a signer from `window.ethereum` will be used. |
| reason?            | `string`            | Reason for the revocation.                                                                                                     |
| rpcUrl?            | `string`            | Optional RPC URL.                                                                                                              |
| walletClient?      | `WalletClient`      | Optional `WalletClient` from viem to use for transactions.                                                                     |

#### Example

```typescript
const { privateKeyToAccount } = require("viem/accounts");
const delegationPrivateKey = "0x...";
const delegationResult = await delegateSignRevokeAttestation("0x46", {
  chain: EvmChains.baseSepolia,
  reason: "revoke reason",
  delegationAccount: privateKeyToAccount(delegationPrivateKey),
});
const res = await client.revokeAttestation(delegationResult.attestationId, {
  reason: delegationResult.reason,
  delegationSignature: delegationResult.delegationSignature,
});
```