Senior Backend Engineer – SQL, Security, Payments & Platform Architecture

Role Overview NENN is seeking a Senior Backend Engineer to lead the stabilization, security hardening, and production readiness of an AI-assisted MVP PIMS platform. This system is being actively built with AI-generated components and requires an experienced engineer who can identify hidden risks in code, database design, and integrations, then systematically transform it into a secure, scalable, and reliable production platform. A core requirement of this role is advanced SQL expertise, including the ability to review and correct AI-generated database structures and queries. In addition, this role will own security architecture, data governance, and Stripe payment integration. The goal is to prepare the platform for public demonstration and trade show readiness by December.Core ResponsibilitiesArchitecture Ownership & System StabilizationAudit current MVP architecture (backend, database, APIs, hosting)Identify structural weaknesses introduced by AI-generated codeDefine a scalable backend architecture (services, data flows, boundaries)Reduce technical debt and enforce maintainable patternsEstablish environment strategy (dev / staging / production)SQL & Data Layer Ownership (Required Core Skill)Design and normalize relational database schemas (PostgreSQL or equivalent)Review and correct AI-generated SQL code and schema designOptimize queries, indexing strategies, and execution plansIdentify data integrity issues (duplication, inconsistency, race conditions)Implement audit trails and data lineage where neededEstablish backup, restore, and disaster recovery processesSecurity & Risk Mitigation (Critical)Perform full application security assessment (OWASP-aligned)Identify vulnerabilities in:Authentication & session managementAPI endpointsDatabase access patternsThird-party integrationsImplement:Role-based access control (RBAC)Encryption at rest and in transitSecure secrets managementDefine logging, monitoring, and breach detection strategiesEnsure data privacy and compliance readiness (as applicable)Payments & Stripe Integration (Required)Architect and implement secure Stripe integration for:Subscriptions (if applicable)One-time paymentsInvoicing and billing workflowsEnsure PCI-safe design (no sensitive card data stored)Handle webhook validation and idempotency correctlyDesign payment state tracking in the databasePrevent double-charging, race conditions, and webhook spoofingBuild reconciliation and payment audit mechanismsAPI & Integration LayerBuild and maintain RESTful APIs (or equivalent architecture)Evaluate third-party APIs for reliability and failure modesImplement robust error handling and retry logicEnsure system resilience under partial outagesAI- Generated Code Governance (Key Requirement)Review AI-generated backend and SQL code for correctness and safetyIdentify hallucinated logic patterns, unsafe queries, or broken assumptionsRefactor AI-generated code into production-grade standardsEstablish coding standards for future AI-assisted developmentRequired Qualifications5+ years backend engineering experienceExpert-level SQL (mandatory)Strong experience with PostgreSQL/MySQL or equivalentProven ability to review and repair AI-generated codebasesDeep understanding of backend security principlesExperience with Stripe or equivalent payment systemsStrong API design and integration experienceExperience with system architecture and scaling applicationsFamiliarity with cloud infrastructure (AWS, GCP, or Azure)Preferred QualificationsExperience with AI-assisted development environmentsExperience in SaaS or operational logistics platformsReact familiarity (not required)Experience in healthcare, veterinary, logistics, emergency response, or field operations systemsDevOps / CI/CD experience.CompensationCommensurate with experience (Range $150,000-$200,000)