Oleksandr Tkach

Specialization

Senior Frontend Engineer · Web3 & DeFi

Based in

Lviv, Ukraine

Connect

Let's meet!

I'm Oleksandr Tkach. Senior Frontend Engineer · Web3 & DeFi.

Name: TUWA SDK
Author: Oleksandr Tkach

Portfolio

Key Projects I've Contributed To

Quasar

Transaction indexing and cloud sync backend with webhooks and multi-tenant auth — running as a managed SaaS in public beta and published as the open-source, self-hosted Quasar Community Edition (Apache-2.0).

Next.jsNestJSPostgreSQLRedisDrizzle ORMPayload CMSDockerBullMQTraefikGitHub ActionsViemSolana Kit

Editions

Quasar Cloud Community Edition Live Showcase

TUWA Open Source Packages

Open-source (Apache-2.0) TypeScript packages for self-custodial apps on EVM and Solana: multi-chain helpers (Orbit Utils), CAIP-122 sign-in (SIWX), wallet connection (Satellite Connect), transaction tracking (Pulsar), React components (Nova UI Kit) and one SDK that brings them together.

TypeScriptZustandImmerReactViemSolana KitWagmiTailwind

Ecosystem Packages

Orbit Utils SIWX Pulsar Satellite Connect Nova UI Kit TUWA SDK

About me

Background & Philosophy

I've spent 7 of my 8+ years in frontend on DeFi. At Aave I worked on the app frontend through V1, V2 and V3, and at BGD Labs I built the Aave Governance V3 interface and the data tools behind it, cutting RPC costs by 30%. That work led me to TUWA: open-source TypeScript packages for wallets, sign-in and transaction tracking on EVM and Solana, a React design system, and Quasar, the backend that keeps it all in sync. I care about interfaces that stay clear and fast when the data is dense and the stakes are real.

Resume

Experience & Education

My journey through education and professional development in software engineering.

Open Source Projects

Self-Hosted Transaction Indexing Engine (Quasar Community Edition)

2026 - Present

TUWA (Core Open Source)

Apache-2.0 single-tenant edition of Quasar: NestJS engine with two-phase EVM & Solana tracking, partitioned PostgreSQL, signed webhooks and a Payload admin with TOTP 2FA. Generated from the production codebase by an automated pipeline (dead-code pruning, leak gates) and released after every production deploy as signed Docker images.

NestJSPostgreSQLBullMQPayload CMSDockerGitHub Actions

Multi-Chain Sign-In (SIWX)

2025 - Present

TUWA (Core Open Source)

One CAIP-122 sign-in flow for EVM and Solana wallets, verified on the app server: EIP-191, EIP-1271 and ERC-6492 on every EVM chain, ed25519 on Solana, single-use nonces, sessions and JWT + JWKS for external auth providers.

TypeScriptViemSubtleCryptoNPM

Multi-Chain Core Utilities (Orbit Utils)

2025 - Present

TUWA (Core Open Source)

Multi-chain helpers for EVM and Solana: chain and account IDs (CAIP-2, CAIP-10, CAIP-19), cached viem and @solana/kit clients, ENS and SNS names, and ERC-4337 smart accounts.

TypeScriptViemWagmiSolana KitNPM

Web3 Transactions Tracking (Pulsar Core)

2025 - Present

TUWA (Core Open Source)

Transaction tracking for EVM and Solana that survives page reloads, with speed-up and cancel detection and trackers for ERC-4337 and Safe.

TypeScriptViemWagmiSolana KitNPM

Web3 Wallet Connection (Satellite Connect)

2025 - Present

TUWA (Core Open Source)

A headless store for EVM and Solana wallet connections: reconnects the last wallet, follows account and network changes made in the wallet and keeps SIWX sessions in sync.

TypeScriptZustandImmerViemSolana KitNPM

Web3 React Design System (Nova UI Kit)

2025 - Present

TUWA (Core Open Source)

A themeable React design system for wallet connection and transactions on EVM and Solana: connect button and modals, transaction toasts and history, design tokens on CSS variables, documented in Storybook.

ReactTypeScriptTailwind CSSFramer MotionStorybookNPM

Quasar API Client (Quasar SDK)

2025 - Present

TUWA (Core Open Source)

The client of the Quasar API for Quasar Cloud and self-hosted Quasar nodes: transaction sync and history for Pulsar from your server, and a CLI that relays webhooks to localhost.

TypeScriptNode.jsREST APINPM

Work Experience

Founder & Lead Engineer

Aug 2025 - Present

TUWA (Core Open Source)

Solo founder of an open-source TypeScript toolkit for EVM and Solana: 25 npm packages for wallet connection, CAIP-122 sign-in and transaction tracking, the Nova UI Kit design system, docs.tuwa.io on Next.js 16, and Quasar, the indexing and sync backend, released as Quasar Cloud and a self-hosted Community Edition.

ReactNext.jsTypeScriptSolanaEVMNestJSPostgreSQL

Software Engineer (Frontend)

Apr 2022 - Mar 2025

BGD Labs

Built and owned the Aave Governance V3 interface, read directly from RPC across several networks, and the data tools that cut RPC infrastructure costs by 30%. Main author of frontend-web3-utils, BGD's library for wallet connection and transaction tracking.

Next.jstRPCZustandViemWagmi

Frontend Developer

Sep 2019 - Feb 2022

Lend / Aave

Frontend developer on the Aave app team across V1, V2 and V3, through to the V3 production launch, implementing UI for the core lending flows.

ReactTypeScriptEthers.jsGraphQLSASS

Frontend Developer

Apr 2018 - Sep 2019

UpTrader

Joined as UpTrader moved from custom development to SaaS and helped build the frontend of its cloud Forex CRM from scratch: the broker back office and the client-facing trader's room. Laid down the frontend architecture with the team, cut response times of critical queries by 30% and was promoted to frontend team lead toward the end.

ReactReduxRedux-SagaJestSCSS