Senior Fullstack Engineer (Rust / TS / React) — x3 Positions

🏢 Summary: Backend Engineer role focused on building and maintaining high-performance financial ledger services that bridge traditional banking systems (ACH, WIRE, SEPA) with blockchain-based stablecoins. The position involves developing secure on-ramp and off-ramp pipelines, queue-based transaction processing, and integrations with banking and compliance infrastructure. The engineer will work on end-to-end integrations and testing within a TypeScript/Node.js environment. 🗂️ Requirements: Strong TypeScript skills with focus on type safety, Experience integrating banking or payment APIs (ACH, WIRE, BaaS), Experience with asynchronous pipeline architectures and queues, Understanding of blockchain concepts (minting, burning, transaction signing, permissions), Ability to write end-to-end integration tests against real APIs, Experience managing third-party service integrations 📃 Skills: TypeScript, Node.js, PostgreSQL, Vitest, ACH, SEPA, WIRE, Blockchain, Queues, KYC, API 🏢 Description: Backend Engineer (TypeScript) We're building a high-performance financial ledger connecting fiat payment rails and blockchains through service providers. We're looking for a backend engineer to work on integrations that bridge traditional banking (ACH, WIRE, SEPA) with on-chain stablecoins. What You'll Work On Building and maintaining services that connect Banking-as-a-Service providers to our network Implementing on-ramp (fiat to tokens) and off-ramp (tokens to fiat) pipelines with strong idempotency guarantees Designing queue-based processing pipelines for multi-step financial transactions Working with identity/compliance infrastructure: KYC certificates, selective disclosure, encrypted attribute sharing Publishing service metadata for decentralized discovery by wallets and other services Writing integration tests against real APIs and a local blockchain node Tech Stack TypeScript / Node.js (ESM) PostgreSQL Vitest Custom SDK ecosystem What We're Looking For Strong TypeScript skills with emphasis on type safety Experience integrating with banking/payment APIs (ACH, wire transfers, BaaS platforms) Comfort with asynchronous pipeline architectures (queues, retries, idempotency) Understanding of blockchain concepts (token minting/burning, on-chain permissions, transaction signing) Preference for integration tests over unit tests; ability to write tests that exercise real system behavior end-to-end Familiarity with explicit resource management patterns (AsyncDisposable, structured cleanup) Experience working with different third-party integrations Nice to Have Experience with KYC/KYB compliance flows and certificate-based identity Multi-currency system design (FX, per-currency fee structures, decimal handling) How We Work Strong code ownership Small team, high autonomy, direct impact on financial infrastructure Straightforward Recruitment: We respect your time. Our 2-step recruitment process is designed to be efficient and meaningful. Flexible Work Environment: Work from anywhere. Align with sprint goals and deliverables - we trust you to manage your productivity.

🏢 Summary: Contract role focused on leading end-to-end development of complex frontend features using TypeScript and React for large-scale enterprise applications. The position emphasizes scalable architecture, advanced state management, performance optimization, security, and integration with backend services. Involves contributing to Node.js services, CI/CD pipelines, testing strategies, and ensuring high-quality, accessible, and secure UI delivery. 🗂️ Requirements: Strong experience with TypeScript and React, Experience delivering complex frontend features end-to-end, Experience designing scalable frontend architectures, Expertise in state management libraries (Redux, Zustand, React Query), Experience integrating with APIs and BFF layers, Proficiency with Node.js, Experience with performance optimization techniques, Knowledge of WCAG and semantic HTML, Experience with secure coding practices and authentication flows, Experience with CI/CD pipelines and automated testing, Strong debugging and production issue resolution skills, Experience working in Agile environments 📃 Skills: TypeScript, React, Redux, Zustand, ReactQuery, Node.js, HTML, CSS, WCAG, CI/CD, REST, API, BFF, Testing, Jest, Cypress, Security, OAuth, PCI, Cloud, CDN 🏢 Description: Job description: * Own end-to-end delivery of complex frontend features using TypeScript and React, from design through production. * Design scalable, maintainable architectures for large enterprise applications (modularization, code splitting, performance). * Lead state management strategy (e.g., Redux, Zustand, React Query), ensuring predictable data flow and performance. * Build and integrate with APIs and BFF layers; contribute to Node.js services where needed. * Translate product and design requirements into high-quality, accessible UI (WCAG-compliant, semantic HTML, responsive CSS). * Drive performance optimization (rendering, bundle size, network usage, caching). * Establish and enforce coding standards, patterns, and best practices across the codebase. * Conduct code reviews, mentor engineers, and raise the overall engineering bar. * Apply strong, proactive debugging practices to identify, isolate, and resolve issues early across environments. * Diagnose and resolve complex production issues using structured debugging, logging, and observability tools. * Embed security best practices into development (secure coding, input validation, auth flows, data protection), and ensure compliance—especially for payment-related flows. * Collaborate with backend, SRE, security, and product teams to ensure reliable, secure, and scalable solutions. * Contribute to CI/CD pipelines, testing strategies (unit, integration, e2e), and release processes. * Participate actively in Agile ceremonies; break down work, estimate, and deliver iteratively. Nice to Have / Preferred Experience * Experience in payments domain (checkout flows, PCI considerations, transaction handling). * Full-stack exposure with Node.js, API design, and BFF patterns. * Familiarity with cloud platforms and edge/CDN strategies. * Experience with design systems and component libraries at scale. Period from: 2026-05-25 Period to: 2026-12-31

🏢 Summary: Frontend-focused role developing and maintaining scalable React applications with TypeScript, integrated with Node.js backend services and data pipelines. The position involves building production-grade, data-driven solutions, contributing to architecture decisions, and optimizing complex UI workflows. It offers work on a high-impact product within a modern TypeScript and React ecosystem. 🗂️ Requirements: Strong proficiency in React, Strong proficiency in TypeScript, Experience building large-scale production applications, Experience with Node.js and API integrations, Experience with data-driven applications, Understanding of modern frontend architecture, Knowledge of testing practices, Ability to work in cross-functional teams 📃 Skills: React, TypeScript, Node.js, APIs, Microservices, Snowflake, Testing, Architecture, Data, Pipelines 🏢 Description: ✅ Your responsibilities: Develop and maintain scalable React applications with TypeScript across the full frontend stack Collaborate closely with backend engineers, data teams, and product managers to deliver high-quality solutions Ensure type safety, code quality, and maintainability throughout the application Participate in design and architecture discussions, proposing improvements to frontend patterns and integrations Troubleshoot and optimize complex UI and data-intensive workflows Support knowledge sharing and mentor junior developers when needed 🧠 Our requirements: Strong proficiency in React and TypeScript , with experience building large-scale, production-grade applications Familiarity with Node.js backend development and integration with APIs or microservices Experience working with data-driven applications , ideally with Snowflake, data lakes, or pipelines Solid understanding of modern frontend architecture, testing, and best practices Ability to communicate effectively in a cross-functional, high-stakes environment Proactive, self-motivated, and capable of delivering high-quality solutions under tight timelines 🌟 What we offer: Opportunity to work on a premium, high-profile product with global business impact Exposure to a modern TypeScript/React ecosystem, integrated with backend Node.js services and advanced data pipelines Collaborative environment with experienced engineers and product leaders Career growth and technical mentorship in a cross-functional team Competitive employment package and benefits.

🏢 Summary: Fullstack Developer role focused on building and maintaining backend services in Node.js and frontend applications in React/Next.js, with occasional involvement in smart contract development. The position involves working with databases, APIs, and collaborating across backend and blockchain teams in an onsite environment. The offer is targeted at senior-level engineers with strong production experience. 🗂️ Requirements: Strong Node.js/NestJS backend experience, Minimum 5 years of backend development experience, Minimum 2 years maintaining production applications, Strong React and TypeScript skills, Experience with database and API integration, Ability to work onsite in Warsaw (100%), English level B2 or higher 📃 Skills: Node.js, NestJS, Express, React, Next.js, TypeScript, PostgreSQL, MongoDB, API, EVM, SVM 🏢 Description: About BlockyDevs We build end-to-end applications combining fintech-grade reliability with Web3 innovation. Your Role As a Fullstack Developer, you’ll primarily work with Node.js on the backend, React on the frontend, and occasionally contribute to smart contract development. Responsibilities Develop backend services with *Node.js (NestJS/Express)** Build frontend apps with *React/Next.js + TypeScript** Work with databases (PostgreSQL, MongoDB) and APIs Occasionally contribute to smart contracts (EVM/SVM) Collaborate with design, backend, and blockchain teams Requirements Strong backend skills in Node.js/NestJS At least 5 years of experience in backend applications At least 2 years of experience in maintaining production applications Solid frontend skills in React + TypeScript Database and API integration knowledge Experience mentoring mid/junior developers English at least B2 level Ability to work 100% onsite from our office near Metro Plac Wilsona, Warsaw Nice-to-have Microservices and cloud deployment experience Web3 integrations knowledge Rates (B2B/Freelance) Senior: 120 - 180 PLN/h Recruitment Process 1. Intro Call (30 min) – Quick chat about your experience, expectations, and our projects. 2. Technical Interview / Task – Backend (Node.js) and frontend (React) focus, with some discussion of smart contracts. 3. Final Meeting – Culture/fit + project discussion. 4. Offer – Fast decision if it’s a match. 5. Process usually takes 2–3 weeks . 6. Feedback after each stage within a few days

🏢 Summary: Entry-level Backend Engineer role focused on supporting the development of backend services and REST APIs under senior guidance. The position involves contributing to production systems, writing tested and maintainable code, and collaborating within a cross-functional engineering team. Ideal for candidates with foundational Java experience seeking hands-on experience in scalable and secure systems. 🗂️ Requirements: Bachelor's degree in Computer Science or related field (or currently pursuing), Minimum 0.5 years of Java experience, Practical experience with RESTful APIs, Ability to work with HTTP methods, status codes, and JSON, Experience writing SQL queries (SELECT, JOIN, WHERE, GROUP BY) or using ORM, Basic understanding of SQL and NoSQL differences, Knowledge of data structures and algorithms, Ability to use Git in a team environment (branching, pull requests, merge conflicts), Experience writing unit tests, Experience contributing code to production through review and deployment process 📃 Skills: Java, REST, HTTP, JSON, SQL, NoSQL, ORM, Git, JUnit, Pytest, Jest, CI, Algorithms, DataStructures, APIs, Testing 🏢 Description: (5190) About This Role You will be a part of the Engineering team and reports to our Manager, Engineering. You will support the development of backend services and APIs that power customer’s products. Working under close guidance from experienced engineers, you will gain hands-on experience contributing to real-world systems while learning best practices in software development, scalability, and security. Key Responsibilities Support the development of backend services and APIs under direct supervision of senior engineers Assist with writing clean, maintainable, and well-documented code following team standards Help debug, test, and troubleshoot backend systems and services Contribute to small tasks or components within larger projects Collaborate with cross-functional teams including Frontend, Product, and DevOps Participate in code reviews and apply feedback to improve technical skills Assist in writing unit tests and validating functionality Document technical processes and development work Required Qualifications Bachelor's degree in Computer Science or a related field; Currently pursuing is also an option Strong theoretical knowledge of Java, at least 0.5 years of experience Practical experience building and consuming RESTful APIs — HTTP methods, status codes, JSON, request/response handling, basic error handling. Working knowledge of databases — has written real SQL queries (SELECT, JOIN, WHERE, GROUP BY) or used an ORM in production code; understands the difference between SQL and NoSQL at a basic level. Solid understanding of data structures and algorithms — arrays, hash maps, trees, basic Big-O analysis — sufficient to discuss simple coding problems and reason about correctness. Comfortable with Git in a team setting — branching, pull requests, code review, addressing feedback, resolving merge conflicts; has worked in a shared repository with at least one other developer. Hands-on experience writing unit tests for their own code (pytest, JUnit, Jest, or equivalent), and basic familiarity with how testing fits into a CI pipeline. Demonstrated ability to ship code to production — even small features or bug fixes — through a real review and deployment process; ability to clearly describe what they built, how it was reviewed, and how it was tested. Genuine interest in cryptocurrency, blockchain, or Web3 (self-taught is fine — owning crypto, reading, side projects, hackathons) and willingness to learn the regulated FinTech context; English level: Upper-intermediate or higher, sufficient for daily team communication and code review discussions. Bonus: exposure to Linux / command line, Docker basics, message queues (Kafka, RabbitMQ), cloud platforms (AWS, GCP), open-source contributions, hackathon participation, or an active public GitHub portfolio.

🏢 Summary: Senior Frontend Developer role focused on designing, building, testing, deploying, and maintaining a React and TypeScript-based frontend system integrated with backend services and mobile apps. The position involves frontend architecture design, production support, and working within Agile teams to deliver scalable solutions used across multiple countries. 🗂️ Requirements: 5+ years of production experience with React, Strong hands-on experience with TypeScript, Strong understanding of software engineering principles, Experience with testing and design systems, Knowledge of REST APIs, Familiarity with DBMS such as PostgreSQL or DynamoDB, Degree in Computer Science, Experience working with Agile methodologies (SCRUM or Kanban), Experience using AI tooling 📃 Skills: React, TypeScript, JavaScript, HTML, CSS, REST, PostgreSQL, DynamoDB, Testing, DesignSystems, Agile, SCRUM, Kanban, AI 🏢 Description: About the role You will need to be an expert in frontend development with a thorough understanding of the technologies involved. Strong frontend skills where you can demonstrate your ability to apply these technologies, as well as deploy and maintain them will be crucial to success. Technologies we work with: React, TypeScript, JavaScript, HTML, CSS, Cypress, Playwright, Node.js, REST APIs, AWS, Terraform Responsibilities: Designing, writing, testing functionalities for a frontend system written in React & TypeScript Design frontend software architecture with connection to backend services and mobile apps Deploying and maintaining frontend / backend applications Maintaining system on production used by consumers from several European countries Debugging issues Scoping and assessing the complexity of features Participating in sprint planning, daily sprints and meetings with product owners for grooming new features Collaborating with other team members and teams who depend on functionalities that you develop Recruiting and mentoring new team members Required qualifications: 5+ years of production software development experience in React Strong understanding of software engineering principles, testing, design systems Solid hands-on experience in TypeScript Know-how of REST APIs Familiarity with DBMS like PostgreSQL, DynamoDB Computer Science degree AI Tooling usage Able to work with Agile methodologies such as SCRUM and/or Kanban Good communication and collaboration skills Self-motivation, proactive attitude Proficiency in English Nice to have: Exposure to backend development (can be in TypeScript) Some experience or interest in developing Cloud and Infrastructure solutions with AWS and CI/CD processes supported by tools like Docker, Kubernetes, Jenkins, Terraform, CircleCI, GitlabCI, Datadog, etc.

🏢 Summary: Frontend Developer role focused on designing, developing, testing, deploying, and maintaining React and TypeScript applications used across multiple European markets. The position involves working with modern frontend technologies, integrating with REST/GraphQL APIs, and supporting production systems. The role requires strong software engineering expertise and collaboration within Agile teams. 🗂️ Requirements: 5+ years of production experience with React, Strong proficiency in TypeScript, Strong understanding of software engineering principles, Experience with testing and design systems, Experience with REST APIs, Experience with GraphQL APIs, Familiarity with PostgreSQL or DynamoDB, Computer Science degree, Experience with AI tooling, Experience working in Agile (SCRUM or Kanban) environments 📃 Skills: React, TypeScript, JavaScript, HTML, CSS, Cypress, Playwright, Node.js, REST, GraphQL, AWS, Terraform, PostgreSQL, DynamoDB, Docker, Kubernetes, Jenkins, CircleCI, GitlabCI, Datadog 🏢 Description: About the role You will need to be an expert in frontend development with a thorough understanding of the technologies involved. Strong frontend skills where you can demonstrate your ability to apply these technologies, as well as deploy and maintain them will be crucial to success. Technologies we work with: React, TypeScript, JavaScript, HTML, CSS, Cypress, Playwright, Node.js, REST/GraphQL APIs, AWS, Terraform Responsibilities: Designing, writing, testing functionalities for a frontend system written in React & TypeScript Deploying and maintaining frontend / backend applications Maintaining system on production used by consumers from several European countries Debugging issues Participating in sprint planning, daily sprints and meetings with product owners for grooming new features Collaborating with other team members and teams who depend on functionalities that you develop Required qualifications: 5+ years of production software development experience in React Strong understanding of software engineering principles, testing, design systems Solid hands-on experience in TypeScript Know-how of REST/GraphQL APIs Familiarity with DBMS like PostgreSQL, DynamoDB Computer Science degree AI Tooling usage Able to work with Agile methodologies such as SCRUM and/or Kanban Good communication and collaboration skills Self-motivation, proactive attitude Proficiency in English Nice to have: Exposure to backend development (can be in TypeScript) Some experience or interest in developing Cloud and Infrastructure solutions with AWS and CI/CD processes supported by tools like Docker, Kubernetes, Jenkins, Terraform, CircleCI, GitlabCI, Datadog, etc.

🏢 Summary: Senior Node.js Engineer role focused on designing and delivering large-scale fintech solutions, covering technical design, development, testing, and maintenance. The position involves building distributed, secure systems and APIs with strong emphasis on Node.js and ReactJS. The role also includes architectural decisions and mentoring less experienced engineers. 🗂️ Requirements: 5+ years Back-end development experience, 3+ years TypeScript experience, 4+ years Node.js experience, Experience designing distributed systems, Experience designing secure systems, Front-end development skills, Understanding of microservices architecture, Experience designing and maintaining APIs, Experience with REST or GraphQL APIs, Experience with AWS, Knowledge of testing best practices, Upper-Intermediate English level 📃 Skills: Node.js, TypeScript, JavaScript, ES6, ReactJS, REST, GraphQL, AWS, Microservices, DevOps, API, Testing 🏢 Description: We are seeking a highly skilled Node.js expert, who excels as a collaborative team member. The role goes beyond coding, encompassing responsibilities such as handling feature aspects, specifications, technical design, development, testing, documentation, and maintenance. Customer Our client has rapidly become one of Europe’s most swiftly expanding FinTech companies. They oversee all aspects of financial operations, from generating virtual cards to facilitating wire transfers and maintaining customer account balances. As a payment institution, our client provides a platform that integrates financial services into its product, offering features such as account management, card payments, bank transfers, and additional services. Requirements Over 5 years of experience in Back-end software development At least 3 years of experience with TypeScript Over 4 years of experience working with Node.js Strong experience in designing distributed and secure systems Good Front-end development skills Good understanding of microservices architectures Experience in designing, building, and maintaining APIs Experience in building and consuming REST and/or GraphQL APIs Familiarity with DevOps practices Strong experience working with AWS Good knowledge of testing best practices At least an Upper-Intermediate level of English Would be a plus Experience with modern JavaScript and ES6 libraries Responsibilities Design and implement large-scale software solutions and components using multiple technologies, with a primary focus on Node.js and ReactJS Maintain a consistently high level of quality throughout all stages of the development Communicate effectively to collaborate closely with the team and gain full context for complex tasks Follow the best engineering practices, as well as company and client guidelines Play supervisory, advisory, and coaching roles for less-experienced engineers on the team Promote clean code, as well as design patterns and principles

🏢 Summary: The offer is for a senior Node.js engineer to design and deliver large-scale backend solutions within a FinTech platform, covering architecture, development, testing, and maintenance. The role involves building secure, distributed systems and APIs, with strong collaboration across teams and contribution to technical design and best practices. 🗂️ Requirements: 5+ years of backend software development experience, 3+ years of TypeScript experience, 4+ years of Node.js experience, Experience designing distributed and secure systems, Experience with microservices architecture, Experience designing, building and maintaining APIs, Experience with REST and/or GraphQL APIs, Experience with AWS, Knowledge of testing best practices, Frontend development skills, Upper-Intermediate English level 📃 Skills: Node.js, TypeScript, JavaScript, ES6, ReactJS, AWS, REST, GraphQL, Microservices, APIs, DevOps, Testing 🏢 Description: We are seeking a highly skilled Node.js expert, who excels as a collaborative team member. The role goes beyond coding, encompassing responsibilities such as handling feature aspects, specifications, technical design, development, testing, documentation, and maintenance. Customer Our client has rapidly become one of Europe’s most swiftly expanding FinTech companies. They oversee all aspects of financial operations, from generating virtual cards to facilitating wire transfers and maintaining customer account balances. As a payment institution, our client provides a platform that integrates financial services into its product, offering features such as account management, card payments, bank transfers, and additional services. Requirements Over 5 years of experience in Back-end software development At least 3 years of experience with TypeScript Over 4 years of experience working with Node.js Strong experience in designing distributed and secure systems Good Front-end development skills Good understanding of microservices architectures Experience in designing, building, and maintaining APIs Experience in building and consuming REST and/or GraphQL APIs Familiarity with DevOps practices Strong experience working with AWS Good knowledge of testing best practices At least an Upper-Intermediate level of English Would be a plus Experience with modern JavaScript and ES6 libraries Responsibilities Design and implement large-scale software solutions and components using multiple technologies, with a primary focus on Node.js and ReactJS Maintain a consistently high level of quality throughout all stages of the development Communicate effectively to collaborate closely with the team and gain full context for complex tasks Follow the best engineering practices, as well as company and client guidelines Play supervisory, advisory, and coaching roles for less-experienced engineers on the team Promote clean code, as well as design patterns and principles

🏢 Summary: Senior React Native Engineer role to build a greenfield mobile application for a digital asset bank, with full ownership over architecture and key technical decisions. The position involves close collaboration with the Tech Lead and backend teams to deliver a secure, scalable fintech product. 🗂️ Requirements: Experience in banking or fintech, Strong experience with React Native, Experience in mobile development for iOS and Android, Ability to design application architecture, Ability to make and justify technical decisions, Experience with TypeScript, Experience with state management, Experience with testing in mobile applications, Experience with CI/CD pipelines, Experience with AI coding tools 📃 Skills: React, ReactNative, TypeScript, iOS, Android, CI/CD, Copilot, Swift, Kotlin, Blockchain, Crypto, Testing, StateManagement 🏢 Description: We are looking for an experienced Senior React Native Engineer to build a mobile application from scratch for a digital asset bank. The role involves designing architecture, making key technical decisions, and working closely with the Mobile Tech Lead. Key requirements: Experience in banking/fintech (required) Strong expertise in React Native and mobile development (iOS/Android) Ability to make and justify technical decisions based on past experience Solution-oriented and proactive mindset Knowledge of TypeScript, state management, testing, and CI/CD Experience with AI coding tools (e.g., Copilot) Nice to have: Knowledge of crypto/blockchain Native mobile experience (Swift/Kotlin) Understanding of mobile security best practices Responsibilities: Build a mobile app from scratch (greenfield) Define architecture and standards Propose solutions and analyze trade-offs Collaborate with backend teams and the Tech Lead