Senior Backend Engineer (Platform & Architecture) - AppSec Solution

OX Security; Polska; On-site; PLN 180,000 - 320,000; Full time

Job summary

OX Security is seeking a Senior Backend Engineer to shape the architecture and infrastructure of our AppSec Solution group. You will work with Software Architects, R&D leads, DevOps and Product to enable AI agents inside the product at scale.

Bring 7+ years of backend experience, strong Node.js/TypeScript production skills, and a proven track record in platform engineering and cross-team collaboration.

Qualifications

• 7+ years of backend engineering experience
• Architect-level depth in system design
• Production experience with Node.js and TypeScript
• Deep experience with Kubernetes and DevOps practices
• Track record leading cross-team technical projects and influencing without formal authority
• Clear written communication: design docs and technical reviews

Responsibilities

• Own cross-company infrastructure and architecture projects end-to-end
• Build and own shared foundations and standards for services
• Lead evolution of data layer as customers scale
• Build platform foundations for running AI agents inside the product
• Drive cost optimization and scaling on Kubernetes
• Raise reliability and observability across services
• Lead AI-enabled development with strong engineering standards
• Coordinate with team leads, DevOps, and Product to move initiatives forward
• Review designs and promote reuse across R&D teams
• Stay hands-on by writing platform code across teams

Skills

Architect-level system design

Backend engineering

Cross-team collaboration

AI-first mindset

Performance optimization

Cloud/Docker/Kubernetes mindset

Communications skills

Tools

Node.js

TypeScript

Kubernetes

Job description

OX Security is securing the AI-driven SDLC from prompt to production. We're building the next generation of security technology for a world where AI is changing how software is built, deployed, and attacked.

We're growing fast and looking for a Senior Backend Engineer to join our AppSec Solution group, home of OX's core platform, and play a key role in shaping the architecture and infrastructure the whole product runs on.

This is a high-impact, cross-functional role where you'll work closely with our Software Architect, team leads across R&D, DevOps and Product, helping us build the foundations for what comes next, including running AI agents inside the product at scale.

If you're independent, opinionated and love turning a design on a whiteboard into a production system, we'd love to meet you.

What You’ll Be Doing

• Own cross-company infrastructure and architecture projects end-to-end with our Software Architect, from design through adoption across teams
• Build and own the shared foundations and standards our services are built on
• Lead the evolution of our data layer as our largest customers scale
• Build the platform foundations for running AI agents inside the OX product
• Drive cost optimization from the application side, including how our services scale on Kubernetes
• Raise the reliability and observability bar across our services
• Lead how R&D builds with AI, so AI-assisted development is fast and meets our engineering standards
• Lead technical alignment with team leads, DevOps, and Product: bring a clear point of view and move cross-team initiatives forward
• Act as an internal partner for engineering teams: review designs, find reuse, and raise the architectural bar across R&D
• Stay hands-on: write platform code and land changes across teams

What We’re Looking For

• 7+ years of backend engineering experience, with architect-level depth in system design
• Strong production experience with Node.js and TypeScript
• AI-first: you build with AI tools every day, adopt new AI technologies early, and look for ways AI can improve developer experience and system performance
• Deep experience with databases at scale: data modelling, performance, and evolving a data layer in production
• Proven hands‑on experience in platform engineering and infrastructure, including shared foundations adopted across teams
• Hands‑on experience with Kubernetes and a strong understanding of DevOps practices
• Track record of leading cross-team technical projects and influencing without formal authority
• Clear written communication: design docs and technical reviews

Nice to have

• Practical understanding of LLMs and AI agents
• Experience with cloud cost optimization
• Background in cybersecurity or SaaS
• The "AI-First" Spark: You are an early adopter of AI technologies and are passionate about finding ways to use AI to improve developer experience and system performance.