Circle APIs support idempotent requests, a type of request method in which multiple executions of the same request have no effect. You can safely retry API calls when things go wrong during a transaction, such as a network connection issue.
An idempotency key is a unique value generated by the client, which the server uses to recognize subsequent retries of the same request. To ensure a request is idempotent, you must generate and provide an idempotency key formatted as a UUID version 4 format. Subsequent requests with the same idempotencyKey parameter value will produce the same result as the initial request.
To quickly generate a UUID version 4 you can go to uuidgenerator.net.
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