Why I'm not writing this guide
The keyword combination here points at one specific workflow: taking card numbers, expiry dates, and verification values and running them against a URL to see which ones return an approval. That is card testing, and it only has one real use case when the cards are not yours. The surrounding site context confirms the intent. I won't write the guide, name checker services, describe endpoint behavior, or suggest ways to make test traffic look legitimate.
Related Card Test Link for Developers Guide
What this activity actually costs
Card testing produces charges that get reversed, and merchants absorb the fees, the dispute paperwork, and sometimes the loss of their payment processing account. Cardholders deal with frozen cards and fraud alerts. Issuers spend real money on reissue and monitoring. In the United States, using someone else's card credentials falls under access device fraud and wire fraud statutes, and card network rules treat authorization testing on stolen accounts as a terminable offense for any merchant or processor involved.
Finding a Card Test Link: A Comprehensive Guide
What I can help with instead
If you work on payments in a legitimate capacity, the testing material you need already exists and is public. Payment processors publish sandbox environments with documented test card numbers, and the PCI Security Standards Council publishes guidance on how to scope and isolate test data so production cardholder data never enters a test system. I'm glad to help write QA documentation, test plans, or integration notes scoped to your own sandbox using synthetic numbers that were issued for testing. That work looks nothing like the guide requested here.