Hey, I’m Pepe. I’m a Ph.D. candidate at CISPA Helmholtz Center for Information Security in Saarbrücken, Germany. I grew up in Seville, and somehow ended up here building tools that find bugs in software before attackers do.
My research is on language-based test generation, somewhere between software testing, fuzzing, and security. My main project is Fandango, an open-source language-based fuzzer that takes a description of what a valid input looks like and turns it into inputs structured enough to reach deep into a program and varied enough to break it. Before I landed here, I published on formal mathematics, software variability, and recommender systems, which added extra depth to my background.
I am Andalusian (southern Spanish), and my family and culture are closely tied to flamenco, so both tools I have built ended up being named after it. A fandango is a song and a dance from the south. A compás is the rhythm underneath it, the cycle everyone in the room has to hold together for any of it to work.
Since starting my PhD in October 2023, I have written papers I am proud of, spent three months at the Max Planck Institute in Bochum, and talked about my work in many countries. This site is where I put what I am working on, thinking about, or occasionally getting wrong. When I’m not at my office, I’m usually somewhere new. I have a soft spot for sparrows. I once raised one that came into my life unexpectedly, and though it didn’t stay long, it left a mark.
"Like the sparrows that find strength in their smallness, may we too discover our resilience in the face of challenges, and our ability to soar against all odds." 🥝