Idempotency key

A unique value a client attaches to a request so that repeating it after a timeout or an error returns the first result instead of creating a duplicate.

#How it works in CryptoLike

The CryptoLike API accepts an Idempotency-Key header on every POST: up to 128 printable ASCII characters (! to ~), for example your order ID. An empty or whitespace-only header counts as no header; a longer key or other characters answer 400 validation_error for the field Idempotency-Key. A repeated request with the same key returns the original response with Idempotent-Replayed: true, and nothing is created twice. Keys are remembered for 24 hours per API key, so a retry within that window never creates a second payment or payout.

The repeat must be the same request — same method, path and body. A different body with the same key is 422 idempotency.mismatch: use one key per logical operation. If the first request is still running, the answer is 409 idempotency.in_progress: wait and repeat. Only responses below 400 are stored; an error releases the key, so a corrected retry runs again. After 504 timeout, retry with the same key. The official SDKs add the header to every POST for you.

Two more guards work without the header. On POST /v1/invoices, idempotency_by_order_id: true returns the open payment of the same order_id instead of creating a second one. On POST /v1/withdrawals, your payout_id with the same coin, amount and address returns the existing withdrawal, while different parameters are 409 — a retry with the same payout_id does not pay twice. On the receiving side, a webhook handler deduplicates by event_id.

#Example

A CryptoLike payment request with an idempotency key: if the connection drops before the answer arrives, send the same request again — same key and body, signed afresh with a new timestamp at least one second later — and you get the same payment back. $KEY_ID, $TS and $SIG are the signing values from the API authentication guide:

curl -s https://api.cryptolike.net/v1/invoices \
  -H "Content-Type: application/json" -H "Idempotency-Key: order-A-1001" \
  -H "X-API-Key: $KEY_ID" -H "X-Timestamp: $TS" -H "X-Signature: $SIG" \
  -d '{"amount":"10.50","currency":"USD","order_id":"A-1001"}'