MioHint is a novel white-box API testing approach that leverages large language models to intelligently mutate test cases, significantly improving coverage where traditional methods fail.

• Overcomes fitness plateaus in API testing by using LLMs to provide gradient guidance where coverage metrics are insufficient
• Enables testing to reach strict conditions in cloud application APIs that were previously difficult to test effectively
• Combines code comprehension capabilities of LLMs with systematic testing approaches to generate more effective test mutations
• Improves security posture by identifying potential vulnerabilities in API implementations that could otherwise remain undiscovered

For security teams, this approach offers a powerful new way to strengthen cloud application reliability by uncovering API issues that traditional testing misses, reducing the risk of exploitable vulnerabilities in production systems.

LLM-assisted Mutation for Whitebox API Testing