Alex K.
AI & Backend Engineer | LLM agents, Harness, Cloud-Native Backends
I am a Senior Software Engineer focused on backend systems, LLM agents, and developer automation. My main specialization is building reliable agent harnesses: the engineering layer around LLMs that handles tools, context, workflows, validation, retries, structured outputs, API integrations, and production behavior. I work primarily with Java, but I also use Rust, Go, and Python for infrastructure, automation, performance-sensitive components, and AI-related systems. I have strong hands-on experience with modern coding agents and AI engineering tools. I use Codex, Claude Code, and Gemini in my daily development workflow, and I understand how to use them effectively for task decomposition, implementation, code review, testing, refactoring, and debugging. I have also worked with Cursor and Antigravity, and I am familiar with OpenClaw, Hermes, and similar agent architectures. I am the author of golemcore-bot, an LLM harness project focused on practical agent runtimes and automation systems. I have also worked on multiple specialized harnesses for LLM-based workflows involving tool execution, context management, structured outputs, API integration, and robust error handling. My background is backend-heavy: Java, Spring, distributed systems, cloud-native services, databases, messaging, Docker, Linux, CI/CD, and production troubleshooting. I value clean architecture, pragmatic testing, maintainable code, and simple designs that can scale without becoming fragile. Technologies I commonly work with include Java, Spring, Maven, Gradle, PostgreSQL, MongoDB, Redis, Kafka, Docker, Git, Linux, AWS, Google Cloud, JUnit, Mockito, Rust, Go, and Python. I can help with backend engineering, LLM agents, coding agents, automation platforms, developer tools, cloud-native services, and production-grade integrations.
Earnings and projects
Last 6 months ÷ 6
Last 6 months: $87k
Billed in all: $993,440$993k
$22k in the last 6 months
Across 31 contracts
Earnings, last 30 days
Skill rankings: #1 in 2 skills of 18
Rarest: top 0.11% in Spring Framework, of 880. Ranked by MRR among everyone on Upwork with the skill.
- Spring Framework880 freelancers · 🇩🇴 #1Top 0.11%🇩🇴#1 of 2
- Apache Cassandra82 freelancers · 🇩🇴 #1Top 1%🇩🇴#1 of 1
- Apache Kafka981 freelancers · 🇩🇴 #1Top 0.20%🇩🇴#1 of 3
- Amazon DynamoDB464 freelancers · 🇩🇴 #1Top 0.43%🇩🇴#1 of 1
- Elasticsearch946 freelancers · 🇩🇴 #1Top 0.32%🇩🇴#1 of 1
- #6Golang2,195 freelancers · 🇩🇴 #1Top 0.27%🇩🇴#1 of 6
- #6Rust888 freelancers · 🇩🇴 #1Top 0.68%🇩🇴#1 of 4
- #11Java8,313 freelancers · 🇩🇴 #1Top 0.13%🇩🇴#1 of 13