Jobs Kotlin

We're a US-based product company building a distributed automation platform that orchestrates a physical Android device fleet from a Kotlin/Spring Boot core. The system is in active production use, partially built, and needs a senior backend engineer for completion work — finishing the remaining V1 scope, hardening the reliability layer, and demonstrating sustained unattended operation under production load.
 

Technical surface: Kotlin/Spring Boot 3.2 on Java 17 for the orchestration layer, Apache Kafka for event streaming, Redisson for distributed locking across the cluster, PostgreSQL for transactional state, Neo4j for relationship graphs, Redis for caching. Worker layer is Node.js running Playwright for browser automation and Appium for physical Android device control. Frontend is React/TypeScript/Vite/Tailwind. Production runs on Docker with Jenkins CI/CD and Prometheus/Grafana for observability.
 

What we need: a senior engineer with real Java or Kotlin distributed systems experience, production debugging stories around Kafka consumer rebalancing or distributed lock contention, database engineering at scale, and the judgment that comes from inheriting complex codebases and shipping clean releases out of them. Fluent use of AI-augmented engineering tools (Claude Code, etc) is expected as part of daily workflow.
 

You'd have technical execution authority over how the work gets done, code quality standards, and engineering process. Founder retains authority over what gets built, scope priorities, and tradeoff decisions. This is completion engineering with senior autonomy on execution, not greenfield architecture or product ownership.
 

Engagement is structured as 2-week sprints with milestone-based payment tied to verifiable deliverables agreed at the start of each sprint. First sprint is a behavioral audit of the existing codebase. Subsequent sprints address the prioritized completion scope. Either side can adjust scope or end the engagement at sprint boundaries.

Available immediately. Remote-friendly. Compensation discussed during initial conversation based on your experience and engagement preferences. Direct contractor relationship, no agency markup.

If this fits, send a brief note covering: (1) your strongest distributed systems debugging story, (2) your experience inheriting and shipping production work from partially-built codebases, and (3) when you can start.

Some roles let you pick one platform. This one lets you own them all.

Massive is a fast-growing proxy and AI data infrastructure company. Our Monetization SDK powers millions of users across desktop, mobile, and smart TV — and we're looking for a Senior SDK Engineer to own it.

This isn't a ticket-driven maintenance role. You'll make real architectural decisions, ship across four platforms, and directly impact how millions of users experience our core product. Small team, high ownership, no layers between you and the work that matters.

Responsibilities

✔ Maintain and enhance our existing SDKs across Android/FireOS (Kotlin), Tizen/WebOS (JavaScript), Windows (C++), and iOS (Swift).

✔ Develop new features and capabilities based on business requirements and partner feedback.

✔ Collaborate with backend, infrastructure, and product teams to improve SDK performance, reliability, and user experience.

✔ Research and implement optimizations to minimize resource consumption while maximizing efficiency.

✔ Design and implement robust testing strategies for multi-platform SDK releases.

✔ Create and maintain comprehensive documentation for internal teams and external partners.

✔ Investigate and resolve complex platform-specific issues across different operating systems and devices.

✔ Drive architectural decisions for SDK design patterns and cross-platform compatibility.

Requirements

✔ 4+ years of experience in software engineering with a focus on SDK or library development.

✔ Proficiency in at least one primary language: Kotlin (strongly preferred), JavaScript, or C++ — with willingness to learn others.

✔ Experience with mobile and/or TV platform development.

✔ Strong understanding of memory management, threading, and performance optimization across platforms.

✔ Experience with SDK distribution mechanisms (package managers, build systems, dependency management).

✔ Strong debugging and troubleshooting skills across multiple environments.

✔ Self-directed and comfortable working in a fast-paced startup environment.

Why join Massive?

Fully Remote

You work best when you work where you want. We support a fully remote team so you can live and work where is best for you.

Work from Home Stipend

Being a fully remote team, we want to ensure your home office is comfortable. We provide a $500 WFH stipend to get your space upgraded!

Unlimited Vacation

Take the time you need: relax, rest and recover! We want our team working at their best so take the days you need.

Health Insurance

Our team is our most valuable resource so we do our part in helping cover health insurance for all team members. We offer different benefits based on if you are located in the USA or International.

Health & Wellness Benefit

We care about your well-being. Every team member receives $50 per month toward health and wellness, whether it's for fitness, mindfulness, or self-care.

Continuous Learning

We believe in always growing. That's why we provide $50 per month toward education — online courses, books, or workshops to keep your skills sharp.

Access to Cutting-Edge Tools

As part of our mission, you'll have access to the latest AI and technology tools, helping you stay ahead and do your best work.

Ready to Apply?

Let’s connect and discuss the details!