Regardless of location, you should filter auditors on several non negotiable qualities.

Track record and exploit history
Look for firms that can demonstrate a strong record on mainnet projects. A meaningful signal is a large number of audits without any known client funds lost through contract exploits after the audit. A firm like Softstack, which highlights more than one thousand audits with a zero exploit record, clearly signals process maturity and defensive thinking.

Depth of technical expertise
You want auditors who can handle complex patterns such as upgradeable proxies, cross chain messaging, advanced DeFi primitives and stablecoin mechanisms. Ask for examples of past audits that match your architecture, not just simple ERC based tokens.

Transparency of methodology
A professional auditor publishes or can share a clear methodology that covers threat modeling, manual code review, automated analysis, fuzzing, testing support and retesting. You should understand how they discover issues and how they prioritise them.

Quality of reports
Audit reports should be readable by both developers and decision makers. Look for clear risk categorisation, root cause explanations, suggested fixes, and an honest discussion of residual risk.

Team continuity
Try to avoid firms that rely mainly on anonymous freelancers for core work. You want a stable team, clear quality control and direct access to the people who actually review your contracts.