Senior Backend Engineer (Go)

About the role

Kastcard is building a robust LATAM domestic payment rail and needs a hands‑on Senior Backend Engineer to design and scale production‑grade services. You will work remotely from Brazil, collaborating with product, compliance, and partner teams to deliver reliable, auditable payment systems.

Key responsibilities

• Design and implement Go microservices and APIs that handle fiat payment provider integration, including fallback and routing logic.
• Develop resilient, feature‑flagged rollout mechanisms with safe rollback paths and strong observability.
• Partner with fraud detection, KYC, and compliance flows to ensure transaction security and regulatory compliance.
• Produce functional specifications, technical design documents, and delivery estimates while breaking work into forward‑compatible increments.
• Mentor squad members, conduct code reviews, and raise backend engineering standards.

Required profile

• 5+ years of software engineering experience with a focus on backend development.
• Strong expertise in Go and building production‑grade APIs and distributed systems.
• Experience designing reliable, secure, and auditable systems for money‑movement.
• Ability to work through ambiguity, reverse‑engineer existing flows, and design parallel delivery paths.
• Startup mindset with ownership and execution capability.

Required skills

• Go
• AWS (including ECS Fargate, Aurora/PostgreSQL)
• Containers
• Relational databases (PostgreSQL)
• Streaming/messaging (Kafka)
• Redis
• Kubernetes
• Terraform