> Markdown version of [/jobs/ext/3865959-senior-backend-engineer](https://www.wearedevelopers.com/jobs/ext/3865959-senior-backend-engineer). Every page supports `.md` or `Accept: text/markdown`. Links point to the HTML versions so they work for humans too. Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md).

---

# Senior Backend Engineer

- **Company:** Flexhire
- **Location:** United States (Remote available)
- **Experience:** Expert
- **Contract:** Permanent contract
- **Skills:** Application Programming Interfaces (APIs), Artificial Intelligence, Amazon Web Services, Cloud Computing, Cyber Security, Relational Databases, Cursor, Cryptographic Protocols, PostgreSQL, Microsoft Copilot, Session Management, WebSocket, WebRTC, Alwayson, Real Time Systems, Large Language Models, Backend, Agentic-AI, Fastapi, Kubernetes, Claude, Api Design, Terraform
- **Published:** October 22, 2026
- **Apply:** https://arc.dev/remote-jobs/j/redirect/pthnbbth0h

## About the Role

* 5+ years of backend engineering experience, ideally in consumer AI, real-time systems, or platform infrastructure
 * Strong Python - FastAPI, async patterns, production-grade API design
 * Real-time communication experience - WebSockets, SSE, gRPC, or similar
 * PostgreSQL or comparable relational database experience at scale
 * Strong familiarity with security and encryption protocols and standards
 * Cloud deployment experience on GCP or AWS with Kubernetes
 * Active user of AI-assisted development tools with a genuine point of view on how to use them well
 * Strong written English and proven remote collaboration skills
 * Strong plus: LLM integration experience, E2E encryption or privacy-preserving architecture, edge computing awareness, Terraform, Helm, ArgoCD

## Description

You'll build the backend infrastructure that powers our Agentic OS - the agent runtime, the memory and context layer, the LLM routing system, and the privacy architecture that makes all of it trustworthy. You'll work directly with the CEO and a small, high-trust engineering team across Silicon Valley, Paris.

We're looking for someone who thinks clearly under ambiguity, ships working software over perfect software, and uses AI development tools - Cursor, Claude, Copilot - as a core part of their workflow. We're a lean team building an ambitious platform. AI-assisted development is how we close that gap and we take it seriously.

What You'll Build

 * Agent runtime and orchestration infrastructure - session management, intent routing, tool execution
 * Persistent memory and context layer - encrypted, anonymized, and privacy-compliant from day one
 * LLM routing and multi-provider integration - LLM agnostic by design, supporting regional models globally
 * Real-time communication systems - low-latency APIs supporting always-on contextual awareness
 * Privacy and security architecture - E2E encryption built in, not bolted on
 * Mobile-to-wearables infrastructure - designed to minimize cloud dependency and support edge computing as the platform evolves to hardware