StackHawk and Rentgen can look similar because both test APIs, send imperfect input, and analyze backend behavior. There is some real overlap, especially when malformed requests expose weak validation, unexpected server errors, or incorrect authentication behavior. However, the tools begin at different moments and answer different questions.
Rentgen starts with one working cURL request and turns it into structured API hygiene checks. It explores missing fields, wrong data types, boundary values, malformed payloads, invalid authentication, unsupported methods, and inconsistent responses. The goal is to give developers and QA engineers a fast reality check before a test suite, CI pipeline, or formal security process exists.
StackHawk approaches the same API from an application security perspective. It provides structured DAST across running applications and APIs, integrates with development pipelines, and helps teams identify, prioritize, and manage security findings. This becomes especially valuable when security testing needs to be systematic and repeatable across the wider application.
These tools do not need to compete. Rentgen can expose fragile API behavior while an endpoint is still being built, helping remove basic validation and error-handling problems early. StackHawk can then focus on broader and deeper security weaknesses as part of a mature DevSecOps workflow.
This is Automation Before Automation.
The full comparison is available on Rentgen API Stories: https://rentgen.io/api-stories/StackHawk-and-Rentgen-API-security-scanning-and-API-hygiene-before-automation.html
