At CloudWalk, our Security team doesn’t just react to threats; we engineer systems that anticipate and neutralize them before they ever reach our infrastructure. We are looking for a Machine Learning Engineer to build the intelligence layer of our edge defenses. You won’t just be tuning standard WAF rules or analyzing logs after the fact. You will design, train, and deploy machine learning models directly at the edge to detect anomalies, thwart intrusions, and block sophisticated attacks in real time.
You will bridge the gap between security intelligence and massive-scale data science, turning raw network traffic into a proactive defense mechanism. You'll work alongside red teamers and security engineers, using their attack data to train models that make those exact attack classes obsolete. If you enjoy solving hard scaling problems, weaponizing AI for defense, and protecting billions of transactions, this role is for you.
What You'll Do
- Build edge intelligence. Design and train machine learning models focused on anomaly detection, bot mitigation, and zero-day intrusion detection.
- Deploy at scale. Implement and optimize inference models to run efficiently at the edge, processing massive volumes of HTTP traffic with ultra-low latency.
- Turn attacks into data. Work closely with our offensive security engineers to understand attack vectors, simulate realistic threats, and generate high-quality datasets for model training.
- Automate the defense. Create robust data pipelines that continuously ingest traffic logs, monitor model performance, detect concept drift, and automate retraining based on the latest threat intelligence.
What We're Looking For
- Fluency in Python and SQL, with deep proficiency in ML libraries like PyTorch, TensorFlow, or Scikit-Learn.
- Experience deploying machine learning models into production, specifically dealing with high-throughput, low-latency requirements.
- Strong understanding of web security, HTTP protocols, and common attack vectors (e.g., OWASP Top 10, L7 DDoS, credential stuffing).
- Familiarity with edge computing platforms (Cloudflare, Fastly, AWS Edge) and CDN/WAF concepts.
- Solid software engineering fundamentals. You code daily and can write production-ready services in Python, Rust, TypeScript, or similar languages to integrate your models with our stack.
- Experience with cloud-based infrastructure (GCP/AWS) and managing large-scale datasets.
- Experience with LLMs and Agents.
- As a member of a fully remote and distributed team, you are expected to complete tasks autonomously, being highly collaborative and self-driven.
- Ability to communicate effectively and debate complex technical concepts in both English and Portuguese.
Bonus Points
- Direct experience with the Cloudflare ecosystem, specifically Cloudflare Workers, Cloudflare WAF, or Cloudflare Workers AI.
- Background in cybersecurity, such as building Intrusion Detection/Prevention Systems (IDS/IPS), threat hunting, or analyzing malware.
- Familiarity with payment industry security (PCI DSS, card tokenization, acquiring flows).
- Contributions to open-source security/ML tools, published security research, or CTF participation.
Skills Required
- Fluency in Python and SQL
- Deep proficiency in ML libraries like PyTorch, TensorFlow, or Scikit-Learn
- Experience deploying machine learning models into production
- Strong understanding of web security and common attack vectors
- Familiarity with edge computing platforms and CDN/WAF concepts
- Solid software engineering fundamentals
- Experience with cloud-based infrastructure (GCP/AWS)
- Experience with LLMs and Agents
What We Do
We are democratizing the payments industry in Brazil, by empowering entrepreneurs through technological, inclusive, and life-changing solutions. Based in Brazil, CloudWalk is a high-end global payment network built on modern technology and proprietary blockchain, focused in bringing a revolution to the payment ecosystem for small and medium-sized businesses. As a unicorn, the company has provided its customers with more than R$ 1 billion in savings by charging fair fees on its transactions and is now present in more than 300.000 businesses across 5.000 brazilian cities. With investors such as the Valor Capital Group, HIVE Ventures and Coatue, the company has already raised US$ 365.5 million in investments and R$3.4 billion in FDICs for anticipation of receivables in its network of financial solutions. In 2022, it was the only brazilian fintech to be featured in the "The Retail Tech 100" ranking by CB Insights, on the "Protection Solutions for Payments and Frauds".
