HackerOne - HackerOne provides a platform designed to streamline vulnerability coordination and bug bounty program by enlisting hackers.
Boss - Github, now with bounties
Intruder - Intruder is a security monitoring platform for internet-facing systems.
Bugcrowd - Harness the largest pool of curated and ranked security researchers to run the most efficient bug bounty and penetration tests
Nessus - Nessus Professional is a security platform designed for businesses who want to protect the security of themselves, their clients, and their customers.
Bounties Network - Complete tasks, earn crypto