Blockchain & Backend Engineer

Daniel Z

Information

Available hours \ week
40 h/w
Seniority level
Senior
Years of experience
7 yrs.
Location
Poland, Warsaw
Nationality
Poland
Timezone
(GMT+01:00) Warsaw

Languages

Polish
Fluent (C2)
English
Fluent (C2)

About

Daniel focuses on infrastructure architecture for high-throughput, fault-tolerant services. He is a Senior Infra Architect / Blockchain & Backend Engineer with about 7 years of commercial delivery, fluent in English and comfortable owning technical direction as well as day-to-day execution. His core stack spans Golang, Python, Rust, TypeScript, JavaScript, Solidity plus React Native and React.js for product-facing surfaces. He has built systems end to end, from mobile-first platforms to developer tooling, handling data modeling, API design, smart-contract integration, and long-running inference workflows. Operationally he works with Amazon Web Services, Terraform, Kubernetes, Docker, PostgreSQL, Redis and Grafana, and has shipped features like workload scheduling, game-server lifecycle automation, RPC/indexer plumbing, and documentation modernization, sometimes under tight release windows. Industry exposure includes e-commerce, gaming, cyber-security, AI, media, etc.

Experience

XRPL Foundation

Blockchain Engineer

About the Project

An engineering project delivered for the XRP Ledger Foundation. Attendify provides proof-of-attendance infrastructure for issuing and verifying event credentials as native XRPL NFTs. The SDK and REST API support event creation, batch minting, IPFS metadata, controlled NFT claims, attendee lookup and cryptographic ownership verification. It was designed for conferences, universities, training programmes and online events requiring tamper-resistant attendance records.

  • Blockchain

Responsibilities

• Designed a reusable Node.js SDK and Express API covering the complete event, issuance, claim and verification lifecycle. • Engineered batch NFT minting with XRPL TicketCreate and TicketSequence, including reserve calculations, ticket limits, paginated ledger queries and event grouping through NFTokenTaxon. • Integrated IPFS metadata and encoded content-addressed URIs into native NFTokenMint transactions. • Built destination-restricted, zero-XRP distribution flows using NFTokenCreateOffer and wallet-side offer acceptance. • Implemented challenge-response ownership verification using signed transaction memos, nonce validation, signer recovery and issuer/taxon-filtered NFT queries. • Added attendee indexing, duplicate-claim protection, account validation, structured error handling, JSDoc documentation and automated API tests. • Delivered the implementation as an open-source XRPL Foundation bounty contribution.

Skills & technologies

Ouroboros AI

Harness & Systems Engineer

About the Project

Ouroboros is an AI native level design platform for game studios and 3D production teams. Its spatial-intelligence harness reason about map topology, architecture, interactive objects and their relationships. Integrated agents can transform text or sketches into structured grayboxes and playable environments. Generated worlds remain persistent, editable and exportable, allowing artists and level designers to modify individual assets without regenerating the entire scene. Studios can supply their own mechanics, level design rules, enemies and asset libraries.

  • GameDev
  • Architecture
  • Scientific Research

Responsibilities

• Architected agent harnesses for map ingestion, scene-graph construction, topology analysis, constraint validation and level synthesis. • Built staged generation pipelines spanning semantic planning, intelligent grayboxing, geometry generation, object placement and engine-ready output. • Designed a context layer for injecting project-specific mechanics, level-design rules, interactive-object schemas, enemies and asset catalogues. • Developed evaluation harnesses for reachability, spatial coherence, collisions, scale, gameplay constraints and regression testing across generated maps. • Engineered persistent world representations that preserved object identity and allowed individual scene elements to be edited, replaced or removed. • Translated game-studio requirements into machine-verifiable generation specifications and integration workflows.

Helium

Documentation & DevEx

About the Project

Helium is a decentralized wireless network covering LoRaWAN IoT connectivity and mobile data offload. Following its migration from a custom L1 blockchain to Solana, the documentation had to reflect major changes to wallets, tokens, governance, network data and developer integrations. The Docusaurus-based portal serves application developers, Hotspot operators, device manufacturers and teams running network infrastructure.

  • Blockchain

Responsibilities

- Migrated and reorganized the Docusaurus/MDX documentation around Helium’s post Solana architecture. - Audited legacy L1 content, removed or updated obsolete instructions, rebuilt the page hierarchy and sidebar navigation, and maintained redirects for moved content. - Updated technical guides covering wallets, tokens, governance, network data and IoT infrastructure. - Verified commands, code examples and links against current implementations, ran production builds and dead-link checks.

Skills & technologies

Qualia

Infrastructure & AI Engineer

About the Project

Qualia is an engineering-led product studio building AI infrastructure, developer tooling and production Web3 systems. The work spanned distributed LLM evaluation, long-running inference, AI agent harnesses.

  • Blockchain
  • AI

Responsibilities

• Architected and operated distributed LLM evaluation harnesses for stateful, long-horizon inference workloads. • Implemented checkpoint persistence, run-resumption semantics and failure recovery so interrupted evaluations could continue without restarting from zero. • Coordinated distributed inference workers and workload lifecycles across Kubernetes, Ray and vLLM-based environments. • Instrumented workers with OpenTelemetry traces and metrics, building Grafana dashboards for throughput, latency, retries, failures and worker health. • Developed Python AI-agent runtimes for EVM and SVM, including chain-aware tool execution and transaction workflows. • Led architecture for RPC services, indexers, account-abstraction signing software and EVM/SVM smart contracts. • Mentored five engineers and interns across infrastructure and protocol work.

Workpod Audits

Founder & Lead Developer

About the Project

WorkPod was an EVM security audit marketplace for protocols and dApp teams. Clients could define an audit scope and budget, share their codebase privately, compare proposals from independent auditors, track delivery and release payment through decentralized escrow. The platform also supported attackathons with pay per vulnerability rewards. Files and reports were encrypted and stored on IPFS while completed engagements could issue a non-transferable onchain proof of audit.

  • Blockchain
  • Cyber-security

Responsibilities

- Designed and implemented the platform architecture as Next.js application, backend services and EVM smart contracts. - Built wallet authentication and separate workflows for clients and auditors, covering scope creation, proposals, auditor selection, report delivery, approval and escrow settlement. - Implemented encrypted IPFS storage with wallet-based access for private codebases and audit reports. - Developed onchain proof of audit credentials and flows for vulnerability submissions, review and reward distribution. - Owned deployment, infrastructure, security decisions and technical delivery.

ScentArchive

Lead React Native & Go Engineer

About the Project

ScentArchive is a mobile first discovery and collection app for people who take fragrance seriously. Users can explore perfumes by notes and accords, compare scent profiles, track their collection and record personal impressions. The React Native client is backed by a Go API, with PostgreSQL as the primary data store, Redis for caching and the complete platform deployed on AWS.

  • E-commerce

Responsibilities

• Designed the end-to-end architecture across the React Native client, Go services, data layer and AWS infrastructure. • Built Go APIs for fragrance search, filtering, collections, wishlists and journal entries, including validation, pagination and error handling. • Modelled the fragrance catalogue and user data in PostgreSQL, adding indexes for efficient queries across perfumes, notes, accords and brands. • Implemented Redis caching for frequently accessed catalogue data and search results, reducing repeated database work. • Built the mobile navigation, discovery flows, fragrance profiles and collection-management experience in React Native. • Owned database migrations, cloud deployment, environment configuration, monitoring and technical delivery.

GameWish

Lead Product Engineer

About the Project

Game Bucket is a mobile-first platform for discovering games, organizing a personal backlog and sharing the experience with friends. Players can build custom lists, track what they want to play, are currently playing or have completed.

  • GameDev
  • Consumer Goods
  • Media
  • Social Media

Responsibilities

Designed and built the product end-to-end, including its architecture, navigation, core screens and cross-platform design system. Developed the Expo/React Native mobile app and React web companion.

Socksfor1 & Suhaib

Solutions & Game Developer

About the Project

Large-scale multiplayer game experiences created for major content creators and their audiences. The projects combined custom gameplay multiplayer server, mods and original mechanics with Kubernetes infrastructure engineered to run thousands of concurrent sessions reliably.

  • GameDev
  • Consumer Services
  • Art and Creativity

Responsibilities

Designed and scaled the multiplayer infrastructure, owning workload scheduling, game-server lifecycles and node reliability. Developed custom mods and gameplay systems while leading a multidisciplinary team of developers, artists and animators from concept through delivery.

Skills & technologies