What I am hired for: acquiring, subscriptions with recurring charges, balances and transaction journals, exact arithmetic on money paths, provider webhooks with protection against repeated processing. Around that: third party API integrations, background queues, bots and admin panels. I run the result in production myself.

Commercial work lives in private repositories, so the projects stay unnamed here. The numbers are counted, not estimated.

Content generation SaaS platform

• Acquiring built from scratch on YooKassa: a payment carries a unique idempotency key and a unique provider ID, so a repeated call cannot create a second charge.
• A separate payment event log: webhook received, duplicate ignored, signature check failed, auto renewal attempted, refund initiated, each entry keeping the status before and after.
• Ledger for the internal currency: the balance is always derived from the transaction history.
• BullMQ queue with deduplication by explicit job ID, so the same job is not queued twice.
• Deploy on merge to main with automatic rollback, OpenTelemetry and Sentry in production.
• Five months of work: 1174 commits, 128 merged pull requests, 271 releases, currently v1.50.0. 83 Prisma models, 101 migrations, 5579 tests.

Subscription VPN service, my own product. 14 consecutive months in production, 585 commits, five processes under pm2, 769 tests.

• Four payment providers behind a single payment layer: CryptoBot for crypto, Telegram Stars, YooKassa, bePaid. Adding a provider does not spread across the codebase.
• Recurring charges: the provider notification is verified, then handled idempotently through Redis SET NX with a TTL, so a redelivered webhook never extends a subscription twice.

Currency and crypto exchange service, client project. Amounts stored and computed as Decimal with up to 8 decimal places, no float on any path that touches money. 17 models, 21 unique indexes, 20 migrations, 1333 tests.

Beyond these: a browser strategy game backend with a tick based economy, and more than 20 Telegram bots and client sites since 2024, from scraping and monitoring to third party integrations, admin panels and automation.

My own product line: fraud prevention for TON and Telegram Mini Apps, plus developer tools. nexalix.io · github.com/Nexalix-Labs

• ledgent · public · @nexalix/ledgent on npm. CLI that measures the real token spend of AI agents from local Claude Code session logs. Apache-2.0, zero runtime dependencies, not a single network call.
• agora · public. Spotlight style launcher for Windows on Tauri, opens on Alt+Space.
• Guard · private. Anti sybil and fraud detection API for Telegram Mini Apps and TON. Fastify, PostgreSQL directly through pg and node-pg-migrate with no ORM, Redis, Zod, argon2, the official TON SDK. 198 tests, and the integration suite starts real PostgreSQL and Redis in containers instead of mocks.

These are tools I run myself, on Axum, sqlx, ratatui and egui. Rust is a hobby and an OSS playground, not my commercial stack.

I confirm the cause with a log or a measurement before fixing anything, and I look for every cause, not the first one. "Done" means the tests and a live scenario were run. Changes are surgical and go through a branch and a pull request, so a rollback is one command.

In development since 2021. Almost four years at EPAM Systems in Minsk, from 2021 to 2024: joined as a student intern in my third year at BSUIR, faculty of computer systems and networks, and grew into a senior backend developer on Node.js and TypeScript. Since 2024 I build my own products and take on client work as the founder of Nexalix Labs.

58 of my 72 repositories are private, so the contribution graph below shows a small share of the actual work.