Oleh – PHP, Vue.js, Laravel

A card and wallet platform for businesses and their users. Companies issue and manage payment cards, run multi-currency wallets, control card limits and send users real-time transaction notifications. It connects to a card issuer-processor, payment and FX providers and B2B partners, and runs under PCI DSS requirements.

• Lead backend development of the card and wallet platform built as event-driven microservices;
• Own integrations with the card issuer-processor, payment/FX providers and B2B partners: API migrations, requirement refinement with product, and closing gaps in limits, KYC and status-mapping specs;
• Designed guaranteed-delivery real-time notifications over WebSockets, using Redis Streams as a durable per-recipient event log, persist-then-ack RabbitMQ consumption, Redis Pub/Sub fan-out across instances and client-side deduplication by event ID;
• Drove PCI DSS v4.0.1 scope reduction by moving card data display to the issuer’s hosted iframe/SDK;
• Initiated support for EVM- and Tron-compatible blockchain networks and built an AWS AppConfig configuration client for Symfony services;
• Lead production incident investigations on Kubernetes and write formal post-incident reports;
• Set team engineering conventions across 5 repositories and rolled out AI-assisted development, including shared coding-agent guidelines and an automated AI code review bot for merge requests.

An AI-powered communication app inside Telegram. Users chat with AI assistants through a bot and a Mini App, and the team runs the product from an admin panel.

• Owned technical strategy and end-to-end delivery of the product, from architecture to production, while coordinating a small development team;
• Designed the Laravel backend with Telegram Bot API integration, LLM provider integrations and conversation/user management;
• Built async message processing and AI workflows on Amazon SQS, with Redis for caching and rate limiting;
• Delivered the Vue.js Mini App UI and admin panel on top of the Laravel API, including authentication flows and payment integrations;
• Set up infrastructure and delivery with Docker and CI/CD.

A fintech payments business with two products. The first is a payment platform that processes UPI transactions for the Indian market. The second is a cross-border money transfer platform with multi-currency conversion. Both connect to banks and payment providers, so every transaction status has to be tracked and reconciled reliably.

• Led backend development of the UPI payment platform and designed idempotent payment flows with status reconciliation, retries, callbacks and webhooks across banks and PSPs;
• Owned integrations with UPI providers and banks for routing, settlement, reconciliation and reporting;
• Built Symfony microservices for the money transfer platform, covering transfer processing, FX rates, currency conversion and payment provider integrations;
• Rewrote payment provider integrations as separate Java services, isolating provider failures from the core platform;
• Scaled processing with RabbitMQ message-driven flows, Redis caching and ClickHouse analytics, and set up monitoring and alerting to keep services stable under high load;
• Set engineering standards through code reviews, quality gates, automated tests and CI/CD, and introduced AI-assisted development with an automated AI review of merge requests;
• Worked with product, operations and compliance stakeholders, mentored backend developers and built Vue.js components for internal tools.

The transactions service of an iGaming platform. It handles every player money operation (bets, wins, deposits, withdrawals and balance changes) and connects the platform to external game and payment providers at about 1M requests per hour.

• Led the PHP team owning the transactions service in a platform split into separate services with dedicated teams;
• Kept the service stable at about 1M requests per hour with a Laravel API layer, a lightweight raw PDO data layer on hot paths, Redis caching and queue-based processing;
• Re-engineered the provider integration workflow into a unified integration layer with contracts, callbacks, reconciliation and failure handling, reducing delivery time for new provider features;
• Planned and coordinated releases, ran code reviews and mentored developers, improving delivery processes and code quality across the team.