Full Stack Developer at Stefanini working on mobile and backend applications. Collaborating with teams to enhance payment systems for Brazilian market.
Responsibilities
Develop and evolve the front-of-store (POS) application and associated backend services, ensuring high availability, performance and an excellent user experience.
Work on integration and certification of POS terminals with payment acquirers in the Brazilian market and participate in the app release cycle.
Implement end-to-end features: mobile (React Native) and backend (Node.js/TypeScript).
Integrate and certify acquirer SDKs/APIs and Android POS SDKs (tests for credit/debit, installment payments, refunds, contactless, logs and evidence).
Participate in the app publishing process (Google Play/App Store) or corporate/MDM distribution: versioning, signing and release tracks.
Develop and maintain REST APIs, integrations with legacy systems and third-party services.
Write tests, perform code reviews and collaborate on continuous improvement of quality and performance.
Monitor and troubleshoot production incidents, with team support.
Document technical flows, integrations and key decisions.
Participate in agile ceremonies, estimations and planning.
Support field pilots/certifications when necessary (occasional travel).
Requirements
Experience in software development (Mid-level), including:
React Native (Android-focused)
Node.js and TypeScript (REST APIs)
Integration with SDKs/APIs and best practices for payment flows (idempotency, error handling and timeouts)
Relational database (PostgreSQL) and writing performant queries
Git, basic CI/CD pipelines and environment organization (dev/staging/production)
Monitoring and logging (e.g., Sentry, CloudWatch, Grafana/Kibana) focused on transaction traceability (a plus)
Security and LGPD (Brazilian data protection) applied to apps and APIs (secure storage, encryption, tokens)
Technical English for reading documentation and SDKs
Nice to have / Differentials
Native Android knowledge (Kotlin/Java) sufficient to create/maintain native bridges in React Native.
Practical experience publishing apps (Google Play Console and/or App Store Connect) or corporate/MDM distribution.
Experience with acquirers/TEF in Brazil (Cielo, Rede, Stone, Getnet, PagSeguro, Adyen, PayGo or SiTef/M-SiTef) and EMV certification/homologation processes.
Experience with Android POS devices and SDKs (Gertec, Ingenico, Tectoy/Sunmi).
Offline-first strategies, queues/messaging (e.g., SQS) and resilience in unstable environments.
Fiscal POS knowledge (NFC-e, SAT, CF-e/MFE) and integration with printers.
AWS (EC2/Lambda/SQS/Secrets), Docker and observability.
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