Founding Senior Backend Engineer

Description

Job Summary: NAIIAN is seeking a Founding Senior Backend Engineer to build the core AI-powered platform, developing APIs, authentication, and complex workflows with fundamental impact on architecture. Key Highlights: 1. Build the core platform on which products, data, and AI will live 2. Define how to operate an AI-sensitive platform from day one 3. Technical autonomy and rapid decision-making with the CTO and founding team **Location:** Madrid (Preferably on-site, with high flexibility negotiable) **Compensation:** €70,000–€90,000 gross annual salary + Foundational Equity + Benefits https://jobs.ashbyhq.com/naiian/484b60ad\-4eae\-4dbe\-a222\-418687e3f35b **About NAIIAN and the Challenge** NAIIAN is a well-funded European Deep Tech startup with its founding team based in Madrid. We are building a cloud-based AI-applied platform for clients operating in contexts demanding high operational and decision-making rigor. We work with documents, verifiable sources, permissions, AI-assisted workflows, auditability, and human approval mechanisms. We are looking for our **Founding Senior Backend Engineer** to build the core platform on which products, data, and AI will live—not isolated pieces of a rigid roadmap. This role exists to build NAIIAN’s "engine": APIs, authentication, authorization, RBAC, workspaces, multi-tenancy, audit logs, and integration with data and AI. **Our approach to teamwork:** We firmly believe in the magic that happens when working side-by-side in front of a whiteboard during this critical 0-to-1 phase. Therefore, our ideal scenario is having you join us at our Madrid office. However, we recognize that exceptional talent requires flexibility. If you’re the right person, we’ll collaborate to design a work model (hybrid or concentrated on-site) tailored to your life and the company’s goals. **What impact will you have?** * **Core Foundations:** You’ll build the core platform covering workspaces, users, permissions, documents, evidence, and workflows. * **Architecture and Contracts:** You’ll design APIs and internal contracts connecting frontend, data, applied AI, and cloud—implementing authentication and true logical isolation. * **Complex Workflows:** You’ll implement stateful flows (queued tasks, document processing, partial results, recoverable errors, retries, and cancellation), and build the foundation for approval gates and human review. * **Observability and Traceability:** You’ll add comprehensive functional observability to know exactly what happened, who requested it, how much it cost, which data was used, and which model was involved. * **Operational Innovation:** You’ll create reusable patterns and work with specs, coding agents, and automated verifications to turn ambiguous requirements into tested software. **Why join now?** * You’ll join NAIIAN’s first wave of engineering—before inertia, legacy debt, or a closed platform exist. * You’ll define how to operate an AI-sensitive platform from day one: security, cost, observability, and reliability. * You’ll work directly with the CTO and founding team—with strong technical autonomy and rapid decision-making. * You’ll receive competitive compensation, health insurance, meal vouchers, and significant foundational equity—designed so upside matters if the company captures the opportunity we’re building. * This is a role for someone who wants infrastructure to be an operational advantage—not just support. **Who are we looking for?** * **Track Record:** Senior experience building SaaS products, B2B platforms, or production backend systems—writing maintainable and testable code. * **Technical Depth:** Strong judgment in APIs, data modeling, security, process states, and recoverable errors. * **Product Mindset:** Pragmatic (build well, simplify, avoid premature complexity) and able to collaborate with frontend, cloud, data, and AI teams without waiting for perfect specifications. * **AI-Driven:** Experience or genuine enthusiasm for working with coding agents (Codex, Claude Code, Gemini, or equivalents), maintaining absolute rigor in review. * **Bonus Points:** Experience building products with audit trails/workflows; integrations with LLMs/RAG; event-driven systems (queues/workers); or having been an *early engineer* at a startup. **Tech Stack** We don’t expect expertise across everything—but you should have deep backend proficiency and understand the full stack to build end-to-end autonomously: * **Backend:** Java (Spring Boot / Spring Framework) for core services; Python (Django, FastAPI, or Flask) for AI, data, or worker services. *(Kotlin, Go, or TypeScript/Node.js alternatives fit if your judgment is strong)*. * **Data & AI:** PostgreSQL and AWS Bedrock (Agents, RAG, structured outputs). * **Cloud & Messaging:** AWS, Terraform, GitHub Actions, Docker, ECS/Fargate, and messaging systems like SQS/SNS, Kafka, or RabbitMQ. * **Frontend & Observability:** TypeScript/Next.js (to understand full flows) and OpenTelemetry, Grafana Stack, ELK. **Our Commitment to You** * **Competitive Salary:** €70,000–€90,000 gross annual salary, commensurate with experience. * **Skin in the Game:** Significant foundational equity, designed so upside matters. * **High-Performance Setup:** Your choice of MacBook Pro, 40" Dell monitor, Herman Miller (or equivalent) chair, and peripherals—day one. * **Personal Care:** Health insurance and meal vouchers. * **Total Autonomy:** Full ownership over the backend and very short decision cycles—working directly with the CTO, CPO, and founding team. Data Protection The personal data you share with us during the application process (CV, contact details, professional information, communications, and interview information) will be processed by Naiian solely to manage your application for this position—and, if you provide explicit consent, for future compatible recruitment processes. The legal basis for processing is the implementation of pre-contractual measures at your request (Art. 6.1.b GDPR) and, where applicable, your consent (Art. 6.1.a GDPR). Your data will be retained only as long as necessary to manage your application—and, unless you exercise your right to erasure, up to one year if you authorize retention for future processes. We do not carry out automated decision-making producing legal effects. You may exercise your rights of access, rectification, erasure, objection, restriction, and data portability—or withdraw consent—at any time by emailing the contact address shown in the application form. You also have the right to lodge a complaint with the Spanish Data Protection Agency (www.aepd.es). — Naiian Recruiting Team