This case study details how Catawiki, a leading online marketplace for special objects, enhanced its security measures through a partnership with Bugcrowd. With 10 million unique visitors monthly, Catawiki required robust security to protect its auction platform and internal API. The company previously faced challenges with ineffective pen tests and bug bounties, which failed to identify significant vulnerabilities. By choosing Bugcrowd, Catawiki streamlined its security efforts, utilizing a unified platform for both pen testing and bug bounty programs. The initial pen test conducted by Bugcrowd uncovered four critical vulnerabilities, which significantly informed Catawiki's security roadmap. Following this, the company transitioned to a managed bug bounty program that resulted in discovering three times more vulnerabilities than the industry standard within the first two months. The case study highlights the benefits of improved communication and expertise from Bugcrowd, leading to a more effective security strategy for Catawiki's online operations.