Idempotency key

Fireblocks saves the idempotency key for 24 hours. Any subsequent request within that time frame using the same key will receive the same response as the original request.

We recommend using the idempotency key for all POST requests except for the Create a new transaction endpoint. For that endpoint, we recommend using the externalTxId parameter.

externalTxId parameter

We recommend using the externalTxId parameter when you call the Create a new transaction endpoint. Fireblocks uses this parameter's value as the internal identifier of the transaction that you have on your end. This value is stored on Fireblocks, and Fireblocks will not process any additional transaction requests with the same value. Additional transaction requests with the same value will return a 400 error code.

If you submit a transaction with an externalTxId value and receive a 4XX/5XX error or no response, use the Get a specific transaction by external transaction ID endpoint to verify that the transaction was not created on Fireblocks.