Based on the information available, Diagmart appears to be a legitimate company. It is an Autel Authorized Dealer in the USA, specializing in online auto diagnostic tools. Customer reviews on Trustpilot give Diagmart an average rating of 3.7. On the Diagmart website, the company has a high customer rating of 4.96 out of 5 based on 772 reviews. Additionally, Scamadviser rates Diagmart as very likely not a scam but legit and reliable. However, it's always a good idea to do your own research and use secure payment methods when shopping online.