OWASP

OWASP, the Open Web Application Security Project, is a nonprofit foundation that produces community-led, freely available guidance for making software more secure. For APIs the anchor deliverable is the OWASP API Security Top 10, a periodically-refreshed list of the most common and damaging ways APIs get broken into — broken object level authorization, broken authentication, excessive data exposure, and the rest. It is vendor-neutral, open, and has become the shared vocabulary the industry uses to talk about API risk.

• API Security Top 10 - A ranked catalog of the failure modes that actually take APIs down, refreshed as the threat landscape shifts.
• Community-led and open source - Hundreds of chapters and thousands of contributors produce guidance nobody has to pay to read or adopt.
• Testing and cheat-sheet projects - Practical companions like the ASVS, the API Security Project, and the Cheat Sheet Series that turn the list into checkable practice.
• A common risk vocabulary - Auditors, tooling vendors, and platform teams all name the same categories, so findings travel across tools.

In my own work the OWASP API Security Top 10 shows up as governance rules I can run rather than a poster on the wall — I map each category to Spectral checks and score my APIs against them, the same way I lean on OWASP alongside PCI Compliance when a sector handles sensitive data. It is one of the few security references that survives the move from human review to automated, CI/CD-enforced, and increasingly agent-driven governance, because every category is concrete enough to test for. That makes OWASP less a compliance checkbox and more a machine-checkable baseline for whether an API team is paying attention.