Senior Backend Engineer (Go)

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