When you apply to Zip, a hard credit check is not performed, which means there is no impact on your credit score. However, a soft credit check is run when you apply.
Your credit report may demonstrate your repayment history with other lenders (e.g. retail credit cards, revolving credit cards etc.) This helps in determining whether you can comfortably meet your Zip repayment obligations.
For more information relating to your credit file, please contact Experian directly.