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.

• 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

• 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)

• 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