Principal Java Architect and Hands-On Platform Lead

***Important: Any proposal containing AI-generated or AI-assisted text will be rejected immediately.*** We develop a cloud-based cybersecurity and web-filtering platform used by organizations to manage internet-access and content-security policies. Customers organize their users and devices into groups and organizational structures, define policies and configuration, and distribute the resulting settings to filtering software deployed in their environments. The cloud platform must determine exactly which configuration applies to each customer asset and deliver changes reliably, securely and efficiently. The system is multi-tenant and handles complex relationships among customers, users, devices, groups, policies, rules and lists. It combines a relational database, distributed caching, asynchronous messaging, secured APIs, background processing and cloud infrastructure. About the Role: We are looking for an exceptionally senior architect and engineer to assume technical ownership of this entire cloud platform. This person will be responsible for the architecture and implementation of the backend applications, shared services, databases, caching, messaging, security, deployment and production operation. This is not a management-only or advisory position. You must remain deeply hands-on: reading existing code, investigating production behavior, designing improvements and personally implementing complex or critical changes. At the same time, this is broader than a senior developer role. You will have the authority and responsibility to determine how the platform should evolve, guide the work of other engineers and ensure that changes remain correct across the complete system. What You Will Be Responsible For • Learn the existing platform thoroughly, including its business rules, data flows, dependencies and production behavior • Establish and maintain a coherent architecture across the cloud applications and shared components • Own the correctness of workflows spanning PostgreSQL, Redis, RabbitMQ and client-facing APIs • Design scalable solutions for hierarchical data, inherited configuration and change-impact calculation • Ensure that configuration changes reach every affected customer installation without reaching unrelated tenants or clients • Improve cache generation, invalidation, repopulation and recovery • Design event processing that behaves correctly when messages are delayed, duplicated, retried or received out of order • Protect tenant isolation and strengthen authentication, authorization and permission enforcement • Optimize SQL queries, database structures, cache access, background jobs and high-volume API paths • Diagnose difficult production issues involving concurrency, transactions, stale data, partial failures or performance degradation • Improve service boundaries, API contracts and internal data models • Plan and execute architectural changes without unnecessarily disrupting existing customers • Write production code for foundational, complicated or high-risk functionality • Review technical designs and code from other engineers • Improve automated testing, release safety, logging, tracing and operational visibility • Maintain clear documentation of important architecture and system behavior We are not simply looking for someone who knows a list of frameworks. We need a strong technical mind who can quickly understand a complicated system and take responsibility for improving it. You should have: • Expert-level Java programming ability and extensive hands-on experience with Spring • A history of personally owning large, business-critical backend systems • Strong architectural experience with distributed, data-intensive applications • Deep knowledge of database design, SQL optimization, transactions and concurrency • Practical experience designing systems that combine a relational database, distributed cache and message broker • A clear understanding of consistency, idempotency, retries, ordering and failure recovery • Experience designing secure multi-tenant applications • Strong knowledge of API design, authentication and authorization • Experience deploying and operating containerized applications in a cloud environment • The ability to trace a problem across application code, database activity, cache state, queued events and infrastructure • The judgment to improve an existing system incrementally when appropriate and redesign a component when necessary • The ability to turn complex business requirements into clear and maintainable technical designs • Excellent communication skills and the ability to give other engineers precise technical direction Approximately 15 or more years of serious software-engineering experience is preferred. However, demonstrated technical depth, judgment and accomplishments matter more than the exact number of years. The right candidate will be: • A fast learner who forms an accurate understanding before making major decisions • Creative in finding simpler and more effective approaches • Persistent in identifying root causes rather than treating symptoms • Comfortable challenging existing assumptions when evidence supports a better direction • Decisive when tradeoffs must be made • Detail-oriented without losing sight of the complete system • Able to work independently in areas where the current design or requirements are not fully documented • Personally accountable for the quality and reliability of the finished result Technology Environment The current platform includes: • Java 21 • Spring Boot • Spring Security and Spring Authorization Server • Spring Data JPA • Hibernate and Hibernate Envers • PostgreSQL and Citus • Redis and Redisson • RabbitMQ and AMQP • Liquibase • OAuth 2.0 and JWT • REST APIs • Maven • Azure cloud services and Blob Storage • Docker • Kubernetes and Helm • Azure DevOps CI/CD • OpenTelemetry • JUnit, Mockito and Testcontainers Deep experience with Java, Spring and distributed backend systems is essential. Prior experience with every individual product or library is not required, but you must be capable of mastering and taking responsibility for the complete technology environment. The successful candidate will become the person we rely on to: • Explain how the complete cloud platform behaves • Recognize where its architecture can be simplified or strengthened • Solve its most difficult technical and production problems • Make sound decisions that account for all affected components • Deliver improvements that are correct, measurable and maintainable • Give the broader development team a clear technical direction Please include: • A description of the most complex production platform you have personally owned • The specific architecture and code for which you were directly responsible • An example of a difficult consistency, caching, messaging or concurrency problem you solved • An example of a major system improvement you identified and led • Your hands-on experience with Java, Spring, PostgreSQL, Redis and message brokers • Your experience operating production applications in Kubernetes or a comparable cloud environment • Your current availability and preferred working arrangement Please clearly distinguish your personal work from the accomplishments of the larger team. Selected candidates will participate in a practical technical discussion based on realistic architecture, debugging and system-design scenarios. We are interested in how you understand complicated systems, investigate problems, evaluate tradeoffs and produce workable solutions—not in trivia questions or artificial coding puzzles.