Find and evaluate every API

API posture management is the practice of continuously discovering every API an organization exposes, assessing how each one is configured and what data it handles, and measuring the resulting risk as a posture score. Unlike point-in-time audits, posture management works from live traffic so the inventory stays current as applications and environments change. The goal is a single, always-accurate view of your API attack surface, including shadow and deprecated endpoints, along with a prioritized path to reducing exposure.

Your API attack surface is the complete set of API endpoints an attacker could reach, together with the data and functionality each one exposes. It grows every time a team ships a new service, adds an endpoint, or integrates a third party, and it expands invisibly through shadow APIs (undocumented endpoints) and zombie APIs (deprecated endpoints still serving traffic). Because most organizations underestimate how many APIs they run, mapping the true attack surface is the first and most important step in securing it.

Harness builds your API inventory from observed traffic rather than from specs you have to maintain. By analyzing real requests flowing through your gateways, ingress, and services, it identifies every active endpoint, including shadow and undocumented APIs that never made it into documentation. Because discovery is traffic-based and continuous, the inventory updates automatically as applications change, so it never goes stale between reviews.

Shadow APIs are endpoints that exist in production but are missing from your documentation and inventory, often spun up quickly, for internal use, or by a third-party integration. Zombie APIs are older, deprecated endpoints that were never fully retired and still accept traffic. Both are dangerous because security teams cannot protect or test what they do not know exists. Traffic-based discovery surfaces both automatically so they can be inventoried, scored, and either secured or decommissioned.

A posture score summarizes the risk of an API, or your whole API estate, into a single measurable number. Harness factors in signals such as authentication and configuration weaknesses, exposure to the public internet, sensitive-data handling, and drift from a known-good baseline. The score gives teams a clear way to prioritize the riskiest endpoints first and to track whether posture is improving over time as issues are discovered and hardened.

The OWASP API Security Top 10 catalogs the most common and impactful API risks, such as broken object-level authorization, broken authentication, and unrestricted resource consumption. Strong API posture management addresses the foundation these risks build on: you cannot mitigate a risk on an endpoint you have not discovered. By maintaining a complete inventory, detecting misconfiguration and drift, and mapping findings to the OWASP categories, posture management gives teams a structured, prioritized path to reducing API risk.

An API gateway routes and manages traffic, and a WAF blocks known malicious requests, but neither gives you a complete, risk-scored picture of every API you run. Gateways only see the APIs routed through them, and WAFs focus on request-level threats rather than inventory and configuration. API posture management sits alongside these tools, discovering endpoints from observed traffic (including those outside the gateway), assessing configuration and exposure, and scoring risk so you know what to protect in the first place.