Department: Engineering Location: Brazil Description We're looking for a hands-on Senior Backend Engineer to help build and scale KAST's LATAM domestic payment rails. You'll be a core contributor on the effort to onboard additional fiat payment providers as redundant, hot-swappable rails. You'll work closely with Product, Compliance/Risk, L3 production support, and provider partners to ship reliable, auditable payment systems that meet the LATAM Central Banks’ requirements. Location: remote from Brazil. What You’ll Be Doing - Design and build production-grade backend microservices and APIs in Go - Implement resilient fallback and routing logic across providers (limits, uptime, KYC eligibility) with feature-flagged rollout and safe rollback paths - Partner with the fraud detection flow and onboarding/KYC integration to keep transaction and onboarding flows compliant and observable - Contribute to FSDs, technical design docs, and delivery estimates; break down work into forward-compatible increments and track open dependencies/pendencies - Design reliable, auditable, and secure systems with strong observability and operational workflows - Help raise the bar on backend engineering standards through code review, technical guidance, and mentorship of squad members What You'll Bring - 5+ years of software engineering experience - Strong backend engineering expertise, particularly with Go - Experience building production-grade APIs and distributed systems, including event-driven / webhook-based integrations with third-party providers - Solid understanding of system reliability, security, and auditability, especially for money-movement or transactional systems - Ability to work through ambiguity: reverse-engineer existing flows, freeze interfaces early, and design for parallel delivery when dependencies aren't fully built yet - Comfortable working cross-functionally with product, compliance, operations, and external provider/partner teams - Startup mindset with strong ownership and execution ability - Experience with cloud infrastructure and modern engineering workflows (AWS, containers, relational databases, streaming/messaging) Nice to have - Experience integrating payment providers / payment rails and reasoning about redundancy, provider failover, and reconciliation - Familiarity with PIX and the Brazilian payments landscape, including Central Bank regulatory requirements and named virtual accounts - Experience with KYC/KYB, AML, transaction monitoring, sanctions screening, or fraud/risk tooling - Experience in crypto, stablecoins, or Web3 infrastructure (e.g. BRL ↔ USDC / stablecoin conversion flows) - Experience decoupling tightly-coupled systems into provider-agnostic, adapter-based architectures - Spanish language skills to coordinate with local providers - Experience with AWS (ECS Fargate, Aurora/PostgreSQL), Kafka, Redis, Kubernetes, or Terraform