**Job Description**

An AI\-native platform that lets Swiss fiduciary firms manage client bookkeeping, payroll and compliance through a WhatsApp\-first workflow, backed by a Next.js/Supabase application and n8n automation. We’re hiring a backend\-leaning full\-stack engineer to close a critical security backlog, stabilise the platform for production use, and lay the operational groundwork, CI/CD, observability, staging are needed to onboard more customers safely. You will work directly inside the existing single\-contributor codebase, take full ownership of the n8n automation layer, and be one of two engineering hires driving the technical roadmap (the other being an AI/Agent Engineer).

**Responsibilities**

• Remediate the platform’s active security exposure: enforce authentication and row\-level security (RLS) on every API route; close public database policies exposing payroll and client data; fix a tenant\-isolation bug that allows cross\-tenant access
• Replace n8n’s direct database master\-key access with an authenticated ingestion API that derives tenant identity server\-side, removing the single largest operational risk in the automation layer
• Design and implement a background job queue for heavy, currently synchronous document processing (PDF/XLSX extraction, multi\-account imports) to remove request\-timeout failures
• Make cloud storage private (signed URLs, UUID paths) and put the database schema into version control, paired with a real staging environment
• Build CI/CD pipelines, automated tests, including tenant\-isolation regression tests and baseline observability (logging, monitoring, alerting)
• Harden and maintain the n8n workflows that run the WhatsApp document\-intake and accounting\-automation flows, including error handling, idempotency, and a dead\-letter/retry path
• Implement data\-subject\-rights tooling (export/erase) and an append\-only accounting ledger with reversal entries, in coordination with the company’s external data\-protection advisor
• Redact personal data from application logs and enforce least\-privilege access patterns throughout the stack
• Collaborate with the AI/Agent Engineer on backend integration points for the LLM\-driven agent, tool authorization checks, audit logging of agent actions.

**Your Skills and Experience**

• 4\+ years of professional experience with Node.js/TypeScript in production backend systems
• Strong hands\-on experience with Next.js (App Router) and building/maintaining REST and webhook APIs
• Deep, practical knowledge of PostgreSQL, including Row\-Level Security (RLS) policy design and multi\-tenant data isolation
• Production experience with Supabase, or an equivalent BaaS (Firebase, AWS Amplify), auth, storage and database
• Experience with n8n, Zapier, or a comparable workflow\-automation tool, ideally including securing/hardening automations that touch production data
• Working DevOps fluency: CI/CD pipeline design (GitHub Actions or equivalent), staging environments, secrets management, and basic monitoring/alerting setup
• Solid understanding of authentication/authorization patterns and common web\-application security pitfalls (mass assignment, privilege escalation, injection)
• Comfortable working in and improving a codebase with minimal existing test coverage or documentation. You will be establishing the engineering discipline, not just following it
• Clear written communication in English; able to work asynchronously across time zones.

*Nice to have*

• Experience with Swiss or EU data\-residency / GDPR\-driven architecture decisions
• Familiarity with double\-entry accounting systems, or fintech/regtech products generally
• Experience integrating LLM\-based agents into a production backend (tool\-calling, audit trails)
• Prior experience as the sole or lead engineer on a live production system (start\-up background)