Idempotency keys ensure your API requests to Privy aren’t executed multiple times, preventing duplicated transactions. When provided, Privy guarantees that a request with the same idempotency key will only be processed once within a 24-hour window.

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Required headers

When using idempotency keys with the REST API, include the following header with your request:
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privy-idempotency-key
string
required
A unique identifier for the request, up to 256 characters. We recommend using a V4 UUID.

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When are they necessary?

Idempotency keys are recommended for:
  • Any POST request that triggers state changes or transactions
  • Scenarios where network issues might cause request retries
  • Critical operations where duplicate execution would be problematic
While optional, idempotency keys are strongly recommended for all non-idempotent operations in production environments to prevent double-spends and duplicate transactions.

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How idempotency works

1

First Request

When Privy receives a request with a new idempotency key, it processes the request normally and stores both the request details and response for 24 hours.
2

Subsequent Requests

If the same idempotency key is used again within 24 hours:
  • If the request body matches the original request: Privy returns the stored response without re-executing the operation
  • If the request body differs: Privy returns a 400 error indicating invalid use of the key
3

Key Expiration

After 24 hours, idempotency keys expire. Using an expired key will result in normal request processing.
Changing any part of the request body while reusing an idempotency key will result in an error. Each unique operation should have its own idempotency key.

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Generating idempotency keys

Generate a unique, random string for each distinct operation. V4 UUIDs are recommended for their uniqueness properties. 
import {v4 as uuidv4} from 'uuid';

// Generate a unique idempotency key
const idempotencyKey = uuidv4();

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Examples

import {PrivyClient} from '@privy-io/server-auth';
import {v4 as uuidv4} from 'uuid';

const client = new PrivyClient($PRIVY_APP_ID, $PRIVY_APP_SECRET);

// Generate a unique idempotency key
const idempotencyKey = uuidv4();

const res = await client.walletApi.ethereum.sendTransaction({
  walletId: $WALLET_ID,
  idempotencyKey, // Pass the idempotency key to prevent duplicate transactions
  transaction: {
    to: '0xE3070d3e4309afA3bC9a6b057685743CF42da77C',
    value: '0x2386F26FC10000',
    chainId: 8453
  }
});
For critical operations, store the idempotency key alongside your transaction records. This allows you to safely retry failed operations with the same key.