Kamil Babaev

Software Engineer | Kotlin / Java / TypeScript | FinTech & Distributed Systems

Berlin, Germany Permanent residence

babaevkamil@gmail.com linkedin.com/in/mrmodest github.com/MrModest

Software engineer with 8 years of experience, including 4 years in fintech across wallets, payments and trading. Experienced in owning cross-service reliability and performance initiatives, production rollouts, observability, and distributed systems. Strong Kotlin/Java/Spring Boot/PostgreSQL background, with hands-on TypeScript experience and a track record of supporting engineers and working directly with product and operational stakeholders.

Distributed systems Payments & Wallets Reliability & concurrency Performance Observability Production ownership

Experience

Delivery Hero - Software Engineer

Dec 2023 - Present

Owned reliability improvements to the wallet write path: designed idempotency handling with PostgreSQL advisory locks, found and fixed a race condition that created duplicate records, and extracted the solution into a reusable library available to other teams.
Led the rewrite of synchronous request handlers to a reactive flow in the gateway routing payment traffic; onboarded and supported engineers, defined the client team's load-testing methodology and thresholds, and reduced p95 latency from 700 ms to 300 ms.
Rolled out payment flow v2 to nine APAC countries as part of a mission team replacing a legacy payment monolith with microservices; shipped PSP-integration fixes and closed token-lifecycle and refund-flow gaps across Payments services under hard deadlines.
Owned one country's v2 rollout end to end and acted as the stakeholder point of contact; ramped production traffic from 1% to 100% and retired legacy routing flags after confirming migration completion.
Owned the Wallet teams' monitoring migration from Datadog to Grafana, covering 100+ dashboard panels and alerts; identified a metrics-pipeline bug that made a business metric read 5x lower than reality and became a technical point of contact for Grafana across the Wallet teams.
Diagnosed poor wallet load-test results as a downstream bottleneck, isolated the dependency with a mock to measure true service throughput, and restructured the k6 suite with JSDoc typing for safer maintenance.

Tech: Kotlin, Java, Spring Boot, PostgreSQL, AWS (SQS/SNS, RDS), Kubernetes, ArgoCD, Docker, Drone CI, Grafana/LGTM, OpenTelemetry, BigQuery, k6

Trade Republic - Software Engineer

Jun 2022 - Nov 2023

Optimized application startup time by 30%, reducing deployment downtime and making releases safer.
Conducted candidate interviews and evaluated take-home assessments as part of the engineering hiring process.
Migrated projects from Buildkite to GitHub Actions and migrated build scripts from Groovy to Kotlin DSL, improving build safety and reducing CI/tooling overhead.
Built a Prometheus-to-Looker data pipeline and dashboard, bringing operational metrics into the company's analytics workflow.

Tech: Kotlin, Java, Spring Boot, Vert.x, jOOQ, PostgreSQL, RabbitMQ, Prometheus, Looker, GitHub Actions

Yandex - Software Engineer

Jun 2021 - May 2022

Partnered closely with product managers to prioritize and deliver Yandex.Product, contributing to a 5% increase in e-commerce requests on the Search platform.

Tech: Kotlin, Java, Spring Boot, Hibernate, PostgreSQL, OracleDB, Yandex Table, LogBroker

Kamil Babaev

Software Engineer | Experience continued

Experience - Continued

Skillaz - Backend Developer

Aug 2020 - Jun 2021

Acted as interim Team Lead, facilitating planning, backlog grooming, estimation and daily coordination while handling urgent requests from managers, support and clients.
Implemented version history for client configurations, streamlining technical support and reducing recurring developer workload.

Tech: Java, Kotlin, Spring Boot, MongoDB, ELK

Mobile TeleSystems - Software Developer

Sep 2018 - Aug 2020

Modernized legacy systems and migrated WCF services to Azure Service Fabric while collaborating directly with architects on technical design and implementation.
Refactored application and query logic, reducing complexity and improving page loading speed by 30%.

Tech: Java, Spring / Spring Boot, JavaScript/TypeScript, React, MobX, MS SQL, jQuery, XSLT, PDL

Technical Skills

Core stack: Kotlin, Java, Spring Boot, Kotlin Coroutines, Hibernate, Vert.x, jOOQ
Data & messaging: PostgreSQL, SQL, RabbitMQ, BigQuery, MongoDB
Cloud & platform: AWS, Kubernetes, Docker, ArgoCD, GitHub Actions, Drone CI
Observability: Grafana/LGTM, Prometheus, OpenTelemetry, Datadog, ELK
Testing & tooling: k6, TypeScript, JSDoc, Gradle Kotlin DSL
Additional: Python, React, Linux, Ansible, ZFS

Selected Project

Homeserver - infrastructure as code

GitHub

Ansible-managed home server with ZFS storage, 15+ self-hosted Docker applications, SSO, VPN-only remote access, scheduled multi-remote backups, and observability using Grafana, Prometheus and Loki.

Education & Languages

B.Sc. Computer Science - 2018

Dagestan State University

Languages

English - Full professional proficiency
German - Limited working proficiency
Russian - Native