Senior Software Engineer

About LumxLumx is building the stablecoin payments stack for Latin America and beyond—API-first on / off-ramps, virtual / external accounts, wallets, and compliant FX.

We deliver instant settlements and institutional-grade reliability.

Backed by leading partners (including BTG Pactual), we combine product excellence with security and compliance.The roleWe're looking for a Senior Software Engineer with advanced experience in fintech, payments, and FX to design, build, and operate mission-critical services that power pay-ins, pay-outs, and currency conversion (quoting, rate locks, execution, settlement).

You'll work across API design, event-driven systems, function-orchestrated workflows, and internal ledgers—always with reliability, observability, and idempotency as first-class requirements.What You'll DoOwn core money flows : Design and run services for pay-ins / pay-outs / FX (quoting, rate-lock, execution, netting, and settlement).

Raise reliability bars : Define and meet SLOs / SLIs, implement robust idempotency, retries / backoff, DLQs, and graceful degradation.Build event-driven workflows : Orchestrate function-based steps and long-running sagas for multi-party financial processes.Model money correctly : Evolve our double-entry ledger, reconciliation across entities, and precise amount / rounding semantics.Integrate partners fast : Ship high-quality connectors with banks, PSPs, and FX providers.Harden security & compliance : Apply least-privilege, secrets management, data classification, and auditability by design.Operate what you build : From RFC to runbook—instrumentation (tracing / metrics / logs), on-call, incident response, and post-mortems.Document & mentor : Write clear ADRs / runbooks and help level up the team through reviews and technical guidance.What you bring6+ years building backend services at scale (fintech / payments / FX experience required).

Strong TypeScript + fundamentals; clean modular design and high-quality APIs (REST / JSON; bonus for gRPC).

Deep understanding of event-driven architectures (queues / streams), saga patterns , and function-orchestrated flows.Practical reliability skills : idempotency keys, outbox / inbox, transactional messaging, distributed locking, and concurrency control.Solid data fundamentals : relational modeling ( PostgreSQL ), transactions / consistency, and performance tuning; caching strategies.Engineering excellence : automated testing, CI / CD, feature flags, canaries, and progressive delivery.Security mindset for financial systems and familiarity with regulated environments (KYC / KYB / KYT concepts).

Nice to haveHands-on with workflow / orchestration tools (e.g., AWS Step Functions , Temporal ).

Experience with FX & rate-locking , treasury, reconciliation at multi-entity scale.Knowledge of local rails ( PIX , ACH ), cards, and crypto on / off-ramps.Multicloud exposure and production observability (OpenTelemetry, distributed tracing).

How we workQuality first : strong tests, thoughtful code reviews, security by design.Measure what matters : DORA metrics, SLOs, and data-driven decision-making.Living docs : ADRs, runbooks, and clear incident playbooks.Ownership with context : autonomy, transparency, and tight feedback loops.BenefitsCompetitive compensation + potential equityRemote-friendly with flexible hours (Americas time zones)Learning budget for conferences / coursesLocal holidays and supportive time-off policy