mshykhov

FinTech / Subscription Billing & Payments - Delivered a first-month-free Premium promotion end-to-end for customers making their first card transaction within 7 days of card opening - event processing, idempotent grants, GrowthBook A/B testing, checkout, billing and production monitoring - Resolved a production subscription-billing incident with the team, correcting renewal logic and supporting refunds for customers charged incorrectly - Helped bootstrap and build a standalone Wallet microservice from scratch - architecture, development, setup and GitOps rollout with DevOps, Memberships integration and production payment-data migration - Mentored backend engineers through onboarding, technical design and code reviews - Created reusable Claude Code skills and MCP workflows for development and code review Stack: Kotlin, Spring Boot, PostgreSQL, Kafka, GraphQL, AWS, Kubernetes, Terraform, Testcontainers

Cloud Services Marketplace / Platform Engineering - Designed and implemented a centralized roles & permissions management system, replacing a fragmented Terraform/CI pipeline with a unified solution - cross-environment visibility, audit trail, and a Backstage self-service admin portal (Node.js/TypeScript) - Drove a 15+ module migration to Spring 6, Spring Security 6, and Spring Data 3, including javax-to-jakarta namespace changes - Contributed to the migration from role-based to fine-grained authorization - provisioned Auth0 resource servers across all environments, synchronized permissions and removed legacy authorization components - Resolved critical production bugs in role management - missing permissions, broken propagation, and a platform-wide user-system permissions mismatch - Provided cross-team platform support - code reviews and backend enablement for product teams Stack: Kotlin, Java, TypeScript, Spring Boot, Node.js, Kafka, AWS, Kubernetes, Terraform, OpenFGA

Cloud Services Marketplace / Mobile BFF - Owned the BFF layer end-to-end - 40+ endpoints, 8+ downstream microservices, serving iOS & Android clients - Reduced API response latency by ~40% through parallel execution of downstream service calls - Introduced consumer-driven contract testing (PactFlow) across BFF, mobile clients and microservices, covering all BFF endpoints to detect breaking API changes before release - Architected and documented the API versioning strategy, enabling backward-compatible biweekly releases - Led the Java 17 to 21 migration and the OAuth2 resource-server auth migration - Integrated YouTube as an external content provider into the mobile platform Stack: Kotlin, Java, Spring Boot, REST, OpenAPI, Kubernetes, JUnit, PactFlow

Restaurant Technology / Booking & Payments - Reduced manual accounting workload by 70% within the first year by automating the end-to-end invoicing pipeline - generation, delivery, payment reminders, and order-payment reconciliation - Migrated a legacy invoicing system (10+ Python scripts & Excel) into a production-grade Kotlin microservice processing thousands of invoices monthly across 17,000+ restaurant partners in 12 countries - Integrated Salesforce CRM via REST API, replacing scattered automation scripts with reliable service-to-service data sync - Implemented async processing with Kotlin Coroutines for high-volume reconciliation and reporting workloads - Built financial reporting modules on BigQuery, replacing manual Excel workflows Stack: Kotlin, Java, Spring Boot, PostgreSQL, Redis, GCP, Kubernetes, BigQuery

Outsourcing / Data Extraction & Automation - Delivered 3 production projects end-to-end - from architecture to AWS deployment - Developed a hybrid web scraping engine (Selenium + Jsoup) for large-scale business-data extraction across 50+ target sources - Built an automated news aggregation pipeline - 8+ sources, scheduled collection, PDF & Google Sheets export - Designed an event-driven Discord automation service with configurable moderation rules and persistent audit logging Stack: Java, Spring Boot, PostgreSQL, AWS, Docker, Liquibase