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# Software Engineer - Node / React

- **Company:** Simplex, Inc.
- **Location:** New York, NY, United States
- **Experience:** Expert
- **Contract:** Permanent contract
- **Skills:** Application Programming Interfaces (APIs), Amazon Web Services, Big Data, Database Models, Programming Tools, PostgreSQL, Node.Js, Next.js, Software Engineering, TypeScript, Virtual Memory, Cloud Platform System, ReactJS, AWS Lambda, Agentic-AI, Event Driven Architecture, Material UI, Information Technology, Terraform, Serverless Computing
- **Published:** October 13, 2026
- **Apply:** https://www.juju.com/job/16_396e43d33

## About the Role

As a Senior Engineer, you'll be expected to bring strong engineering principles backed by at least 5 years of experience. The ideal candidate:

 * Has a strong computer science and programming foundation - has read Designing Data-Intensive Applications
 * Is a craftsperson who deeply cares about the quality of their output and understands the long-term costs of shortcuts
 * Builds with the end user and longevity in mind - knows how to design abstractions and APIs that are a pleasure for both customers and teammates to use
 * Communicates effectively to drive clarity and alignment across the organization - able to translate product requirements into technical challenges and vice versa
 * Is genuinely passionate about software engineering and dives deep into topics that interest them, whether that's the Node.js Event Loop or how virtual memory works at the OS level
 * Has hands-on experience with serverless architectures - comfortable designing and deploying serverless functions and event-driven systems in cloud environments (e.g., AWS Lambda, Vercel Edge Functions, or equivalent)

## Description

* Build and own new user-facing features end-to-end, from database models to UI components
 * Continuously improve observability across existing systems - analytics, monitoring, and alerting
 * Collaborate with product and engineering to architect key differentiators, including embedded fintech products and AI agents to help merchants manage their stores
 * Build CI/CD pipelines and developer tooling (e.g., feature environments) that increase development velocity
 * Help shape engineering processes to support building a world-class product

Tech Stack

Familiarity with every tool isn't required, but candidates should have the foundational knowledge to understand what powers them under the hood:

 * Node
 * React
 * Next.js deployed on Vercel
 * Typescript
 * AWS (particularly RDS)
 * PostgreSQL
 * Terraform or equivalent infrastructure-as-code tooling