Staff Machine Learning Engineer (Payments)

Location: Sao Paulo, Brazil; hybrid with an expectation of working onsite three days per week. Employees may work remotely from abroad for up to 30 additional days per year.

Company

hirify.global operates in global digital payments, with a diverse team spanning more than 50 nationalities and 10+ locations.

What you will do

• Define the multi-quarter ML strategy for payment authorization optimization, routing intelligence, and retry strategies.
• Design and lead shared ML infrastructure, including feature stores, model-serving platforms, and experimentation frameworks.
• Establish organization-wide standards for model governance, monitoring, MLOps, reliability, and reproducibility.
• Lead ambiguous, high-stakes problems across multiple engineering, product, data, and platform teams.
• Mentor Senior engineers through design reviews, pairing, stretch opportunities, and technical guidance.
• Design experimentation for live payment traffic using multi-armed bandits, causal inference, and traffic-splitting frameworks.

Requirements

• Experience designing and shipping reusable ML systems and platforms serving multiple products or teams.
• Expertise in classical and applied ML, including XGBoost, LightGBM, calibration, cost-sensitive learning, and problem-ahirify.globalpriate evaluation.
• Extensive experience taking models into high-throughput, low-latency production environments and owning reliability, SLAs, incident response, and MLOps tooling.
• Senior-level Python software engineering skills, with strong standards for testability and maintainability.
• Strong understanding of card payments, issuer behavior, authorization codes, retry logic, network rules, and 3DS.
• Deep experience designing and owning ML infrastructure on AWS or GCP, including infrastructure-as-code, cost management, and build-versus-buy decisions.

Culture & Benefits

• High-trust, people-first environment with autonomy, ownership, continuous learning, and cross-team collaboration.
• 30-day holiday allowance and hybrid work combining office and home working.
• Annual professional development budget of 3,000 BRL, leadership cafés, and on-the-job training.
• Health, dental, life, and travel insurance; enhanced family leave; meal or supermarket vouchers; and transportation support.
• Gym contribution, mental health platform, SESC programs, employee discounts, and a pet-friendly office.