Senior Elixir Engineer

Hack The Box is the leading cyber readiness platform that battle-tests and upskills both humans and AI agents to enhance organizational cyber resilience. Trusted by Fortune 500 companies, government agencies, and MSSPs, it delivers threat-informed learning paths with real-world scenarios in gamified labs and live-fire simulations to build and validate offensive and defensive cyber capabilities. The company has over 4 million members and 800+ enterprise customers, and is headquartered in the UK with additional offices in the US, Australia, and Greece.

• 5+ years of professional backend or full-stack development experience.
• 3+ years of production experience with Elixir and Phoenix.
• Strong knowledge of OTP and the BEAM VM, including processes, supervision, GenServer, and GenStage.
• Hands-on experience with Phoenix LiveView, including components, streams, and JS hooks.
• Deep expertise in Ecto and PostgreSQL including schema design, query optimization, indexing, and migrations.
• Experience with background job systems, preferably Oban, and event-driven architectures.
• Solid testing discipline using ExUnit, property-based and integration testing.
• Familiarity with containerization tools like Docker, orchestration with Kubernetes, and CI/CD best practices.
• Security-minded engineering: solid understanding of OWASP fundamentals, authentication patterns, and secure user data handling.
• Excellent written and verbal communication skills suited for remote and asynchronous work environments.

• Design and build production Phoenix applications, including REST APIs, LiveView UIs, and real-time features using PubSub and Channels.
• Model and evolve data with Ecto and PostgreSQL, ensuring performant queries and zero-downtime migrations.
• Build fault-tolerant systems with OTP technologies such as supervision trees and GenServer.
• Own background processing and scheduled workloads with Oban, utilizing Telemetry and metrics for observability.
• Deliver secure code focusing on authentication/authorization, least-privilege access, and input hardening.
• Deploy and operate services on Kubernetes and GCP, contributing to CI/CD pipelines and release quality.
• Mentor engineers through code reviews, design sessions, and maintaining coding standards.
• Document architectural decisions and communicate effectively in a remote-first environment to foster asynchronous collaboration.

The position is available for candidates located within Europe, specifically mentioning Greece with options for hybrid or fully remote work. For candidates based within 55 km of the Athens office, a hybrid work mode applies, while those beyond that radius can follow a fully remote arrangement. Relocation support is offered including bonuses and tax benefits.