Note: Backend engineer (8 yrs) focused on high-scale, high-stakes systems (payments, data infra, AI tooling).
– Founding engineer at Rent.app: built payments + AML/KYC processing millions in annual payment volume
– At Datafold: built core parts of an AI-powered SQL transpiler used for enterprise migrations
– Worked on validating LLM-generated SQL and large-scale data migration (billions of rows)
I enjoy working on systems where correctness and reliability actually matter (fintech, infra, data platforms).
Backend engineer building high-scale, real-time and data-intensive systems across fintech, infrastructure and AI-driven tooling. Founding engineer in multiple startups, with hands-on experience designing payment and compliance systems (AML/fraud) and leading core backend initiatives. Recently worked on an AI-assisted SQL migration and transpilation platform for enterprise customers
Willing to relocate: London, UK
Technologies: Python, Go, Node.js, LLM (OpenAI, Claude, AWS Bedrock), PostgreSQL, Redis, MongoDB, ClickHouse, Kafka, RabbitMQ, Celery, AWS (S3, Lambda, RDS, EKS, ECS, Fargate), Kubernetes, Docker, Terraform, GitHub Actions, ArgoCD, Datadog, Prometheus, OpenTelemetry
Résumé/CV: https://kostandyan.xyz/files/cv-20260304.pdf
Email: [email protected]
Note: Backend engineer (8 yrs) focused on high-scale, high-stakes systems (payments, data infra, AI tooling).
– Founding engineer at Rent.app: built payments + AML/KYC processing millions in annual payment volume – At Datafold: built core parts of an AI-powered SQL transpiler used for enterprise migrations – Worked on validating LLM-generated SQL and large-scale data migration (billions of rows)
I enjoy working on systems where correctness and reliability actually matter (fintech, infra, data platforms).