Senior Backend Security Engineer: Encryption & PHI

Engg; Warszawa; On-site; PLN 250,000 - 360,000; Full time

Job summary

StackAI is seeking a senior Python engineer to join the Core Engineering team and build security-critical backend systems. You will help shape how StackAI encrypts customer data, manages keys and signatures, and enforces tenant and authentication boundaries across regulated workflows.

This is hands-on backend work in an existing codebase. You will write production Python, drive migrations and rollouts, and partner with security teams to deliver reliable, auditable systems that protect PHI and

Qualifications

• 4+ years of experience building and operating production backend systems.
• Strong professional experience with Python in a substantial production codebase.
• Hands-on experience implementing and operating security-critical product systems, including the code that enforces their guarantees.
• Depth in encryption and key management, signing, authentication, or multi-tenant isolation.

Responsibilities

• Build encryption and key-management systems.
• Protect sensitive data across workflows, connectors, model calls, logs, and storage.
• Secure customer credentials from storage through runtime usage.
• Strengthen tenant isolation, signing, session handling, and service-to-service auth.
• Create shared security foundations with Python services and APIs.
• Plan and execute migrations, rollouts, observability, and rollback.

Skills

Python

Security engineering

Back-end systems

Encryption

Tools

HashiCorp Vault

Cloud KMS

HSMs

Job description

StackAI is seeking a senior Python engineer to join the Core Engineering team and build security-critical backend systems. You will help shape how StackAI encrypts customer data, manages keys and signatures, and enforces tenant and authentication boundaries across regulated workflows.

This is hands-on backend work in an existing codebase. You will write production Python, drive migrations and rollouts, and partner with security teams to deliver reliable, auditable systems that protect PHI and