About
Egor Kravchenko
Senior Full-Stack & Mobile Engineer
Antalya, Turkey · Remote only · UTC+3
Open to senior / staff roles · full-time or contract
I'm a senior full-stack and mobile engineer. I own production systems end-to-end — the API, the data model, and the React Native or web front end that ships them — rather than a single slice of the stack. Right now I'm the founding engineer at Medical Avenue, a medical-tourism platform, where I took over an inherited codebase and have been the sole engineer since; before that, almost five years at NayaOne, an FCA-regulated fintech platform, where I grew from senior engineer to team lead.
Experience
Founding Engineer (Contract)
Medical Avenue · Jan 2026 – Present
Took over a medical-tourism platform from a departed agency team and have been the sole engineer since — owning the React Native patient app, the backend, and the design system end-to-end.
- Cut the inherited React Native app from a 1.2 GB memory peak with OOM kills on real devices to a stable ~350 MB by flattening its navigation architecture — verified on a 2018 Android with 3 GB RAM.
- Added ~70 REST endpoints (Node.js / Prisma / PostgreSQL) for the v2 mobile API on top of an inherited ~120-endpoint platform now under my sole ownership.
- Overhauled auth: slim JWT payloads, a refresh flow that verifies expired-token signatures with machine-readable error codes, Redis-backed sliding-window sessions, Google/Apple OAuth, RBAC, and rate limiting.
- Built a secure file backend on S3-compatible object storage (Cloudflare R2): presigned upload → confirm → download → delete, a default-deny access registry, and append-only audit logging enforced by PostgreSQL triggers.
Senior Full-Stack Engineer & Team Lead
NayaOne · May 2021 – Dec 2025 · London
Enterprise SaaS platform serving 80+ financial institutions in FCA-regulated cloud environments for AI and fintech experimentation. Grew from senior engineer to team lead of five.
- Delivered the launch module behind the FCA–NVIDIA AI Sandbox partnership end-to-end under a one-week deadline.
- Architected automated sandbox provisioning — queue-based Terraform orchestration across AWS, Azure, and GCP — cutting enterprise deployment from days to under one for 95% of projects.
- Cut GraphQL hot-path latency 250ms → 75ms (−70%) for 300+ daily users by refactoring 80+ queries with raw SQL joins and batched cross-database resolvers.
- Built a session-analysis pipeline over 35K+ product sessions that exposed a 70% vendor-onboarding drop-off, then led the 5-person redesign that cut it below 5%.
Full-Stack Engineer
Synergy University · Oct 2017 – May 2021 · Moscow
Built a full-stack loyalty platform (Node.js / Vue.js) with enterprise SSO (Keycloak) and mentored two junior engineers to mid-level within six months.
Outside work I run self-hosted AI infrastructure — local embeddings, hybrid retrieval, and agents over my own knowledge base — and write about the engineering decisions behind all of this: the tradeoffs I actually made, the naive solution that broke, and the lesson that generalizes.
Selected work from these roles is written up as case studies. Full history on LinkedIn.