Hi! We are **Monterail** - a team of over **130+** experts working together to create meaningful software. **Discover your way at Monterail.** We are looking for a **Senior React Developer** to join our team and help us create innovative software as a freelancer. **You are - ideally:**

*   Strong experience with React
*   Proficiency in modern JavaScript (ES6+)
*   Solid experience with state management solutions, particularly Redux and React Context
*   Experience consuming RESTful APIs
*   Proficiency in SCSS for styling; familiarity or a keen interest in Tailwind CSS is highly desirable
*   English skill
*   Availability for full-time cooperation (B2B contract only)

**What do we mean by freelance?**

*   Read more at Monterail Tech Network

**Salary** 90 - 110 PLN/h + VAT (B2B contract only)

Senior React Developer - Freelancer

🚀 Freelance Opportunity: Fullstack Developer (React, Python, LangGraph) – AI Prototyping Project

**Location:** Remote (EU-based)

**Start Date:** ASAP

**Duration:** Until end of Q1 2026 (with possible extension)

**Client:** Leading German E-Commerce Platform

**Engagement:** Freelance / Contract

🧠 About the Project

Our AI prototyping initiative has gained strong momentum, and we’re now looking to **expand our agile development team** with a skilled **Fullstack Developer**. You’ll be working on cutting-edge AI-driven features and tools that will shape the future of e-commerce experiences for millions of users.

🛠️ Tech Stack & Skills

We’re looking for someone with solid experience in:

*   **Frontend:** React (with modern hooks and component architecture)
*   **Backend:** Python (FastAPI or similar frameworks)
*   **AI Tooling:** LangGraph, Pydantic
*   **Bonus:** Experience with LLMs, vector databases, or prompt engineering

✅ What You’ll Do

*   Collaborate closely with AI researchers, product managers, and other developers
*   Build and iterate on prototypes that integrate AI into user-facing and internal tools
*   Ensure clean, scalable, and well-documented code
*   Contribute to architectural decisions and best practices

📅 Timeline

*   **Start:** 01.09.2025
*   **Initial Term:** Until **March 2026**
*   **Extension:** Possible based on performance and project needs

🌍 Why Join?

*   Work with a **forward-thinking, innovation-driven team**
*   Be part of a **high-impact AI initiative** at one of Germany’s top e-commerce platforms
*   Flexible remote setup with a collaborative and inclusive culture

Full Stack Engineer

**Location** Our Senior Full Stack Engineer will be an integral part of our Engineering teams in EMEA. This role is based remotely as a full-time employee in the UK, Ireland, Estonia, the Netherlands, Sweden and Spain. We are also open to contractors in Eastern Europe and Portugal. **Who We Are** DoiT is a global technology company that works with cloud-driven organizations to leverage the cloud to drive business growth and innovation. We combine data, technology, and human expertise to ensure our customers operate in a well-architected and scalable state - from planning to production. Delivering DoiT Cloud Intelligence, the only solution that integrates advanced technology with human intelligence, we help our customers solve complex multicloud problems and drive efficiency. With decades of multicloud experience, we have specializations in Kubernetes, GenAI, CloudOps, and more. An award-winning strategic partner of AWS, Google Cloud, and Microsoft Azure, we work alongside more than 4,000 customers worldwide. **The OpportunityAs a Senior Full Stack Software Engineer**, you will be working on improving the DoiT Cloud Intelligence product with a primary focus on **CloudFlow** — our governance tool that helps customers manage and control their FinOps programs. You'll be implementing new features, contributing to the ongoing development of this strategic and first-of-its-kind platform, and also collaborating on future integrations like **Threads** (integration with systems such as Jira). You’ll work closely with product managers and developers across teams, participate in product decision-making, and have end-to-end ownership of projects. This is an opportunity to help shape a product that sits at the core of DoiT’s platform and product strategy. **Responsibilities**

*   Implementing features. From the proposal, through spec and implementation, to maintenance. You're expected to propose things that you think can be a good addition to the products
*   Reviewing code. We believe in code reviews. And you will soon start reviewing pull requests as well!
*   Improving the health of the codebase. We’re mindful of accumulating technical debt. We dedicate one day per week to housekeeping
*   Providing feedback. The team plans and discusses the upcoming work. We provide feedback to each other, trying to find challenges and unknowns as early as possible

**Qualifications**

*   5+ years of software development experience
*   A Full Stack engineer or a Frontend/Backend engineer with a desire to learn to become a Full Stack engineer
*   A solid understanding of programming languages, ideally knowledge of React framework and/or Go programming language, but if you don’t, you will be willing to learn and fully embrace these languages
*   Advantageous to have experience developing solutions in the Cloud, and/or using Cloud services but certainly not a must
*   Embraces continuous development and learning
*   Knowledge of software engineering practices
*   Demonstrated passion for creating high-quality web/SaaS apps
*   Experience with Git/GitHub
*   Excellent communication skills in English, both written and verbal
*   Self-organized, Goal-oriented, self-motivated individual who is confident, thorough and tenacious
*   Ability to effectively operate with flexibility in a fast-paced, constantly evolving team environment
*   A great sense of humor and enjoys having fun at work

**Bonus Points**

*   BA/BS degree or equivalent practical experience
*   Experience with Google Cloud or AWS services from a production environment

**Are you a Do’er?** Be your truest self. Work on your terms. Make a difference. We are home to a global team of incredible talent who work remotely and have the flexibility to have a schedule that balances your work and home life. We embrace and support leveling up your skills professionally and personally. What does being a Do’er mean? We’re all about being entrepreneurial, pursuing knowledge and having fun! Click here to learn more about our core values. Sounds too good to be true? Check out our Glassdoor Page. We thought so too, but we’re here and happy we hit that ‘apply’ button.

*   Unlimited Vacation
*   Flexible Working Options
*   Health Insurance
*   Parental Leave
*   Employee Stock Option Plan
*   Home Office Allowance

**Many Do’ers, One Team** DoiT unites as _Many Do’ers, One Team_, where diversity is more than a goal—it's our strength. We actively cultivate an inclusive, equitable workplace, recognizing that each unique perspective enhances our innovation. By celebrating differences, we create an environment where every individual feels valued, contributing to our collective success.

Sr. Full Stack Engineer

**Work Type: Contractor | Permanent Remote Compensation: USD 50 – 125/hour Hours: 10 to 40 hours/week (Partial PST overlap required) Experience Required: 5 – 10 Years Contract Duration: 1 Month (Extension based on performance) Notice Period: Immediate preferredNote**

*   This is a contract-based, fully remote role.
*   Only citizens or valid work permit holders from the US, Canada, Australia, or Western Europe are eligible.
*   No medical benefits or paid leave.
*   Contractors must manage their own taxes and compliance.
*   Payment is based on actual hours worked.

**Job OverviewWe're seeking skilled Fullstack Engineers to join cutting-edge AI projects focused on enhancing the performance of Large Language Models (LLMs) in real-world software tasks. Your work will help train, test, and validate LLMs by evaluating AI-generated code, contributing to agent-based applications, and collaborating with a high-performance team of engineers and researchers.You will play a key role in building datasets, testing model responses, and pushing AI systems closer to real developer productivity.Key Responsibilities**

*   Contribute to LLM-focused projects that evaluate AI performance on realistic software engineering tasks
*   Build and lead agent use cases such as coding copilots, creative tools, or automation bots
*   Review and rank 3–4 AI-generated code solutions per task using a structured framework
*   Analyze code diffs for accuracy, efficiency, and readability
*   Construct fullstack tools for data pipeline support and internal testing environments
*   Identify and report edge cases in model outputs, providing well-structured rationale
*   Work closely with researchers and engineers to improve model behavior and code quality

**Must-Have Skills**

*   5+ years of hands-on software engineering experience, including strong fullstack development
*   1+ years full-time (FTE only) at a top 50 tech company if US-based, 2+ years if located outside the US
*   Deep knowledge of software design, code review, debugging, and scalable systems
*   Proven expertise in building production-grade applications using modern frameworks
*   Excellent communication skills for writing clear evaluation rationales
*   Proficient in Git workflows, JavaScript/Python, and cloud platforms (AWS, GCP, etc.)

Senior Developer – Fullstack Apps for AI Agents [1 Month Contract]

Jumpseller is a SaaS solution for small business to manage their online business. We focus on making e-commerce easier for everyone, so businesses can focus on what they do best: building and selling their products. Today, merchants use the Jumpseller platform to manage every aspect of their online business — from products to orders to customers, selling with an online store, on mobile, on social networks and through different e-commerce channels.

At Jumpseller you will find a startup environment in which your contributions matter and you are enabled to grow professionally. We have 2 offices, one in Porto, Portugal, and another in Santiago, Chile, and our working culture is international. We all work fully remote.

We are looking for a Full Stack Developer to join our growing team. We look for skilled & dedicated people who share our passion for building a product that millions of people use.

You Are

*   A bachelor/master in Informatics (or related);
*   Proven professional experience in OO programming and web development;
*   Attentive to details, delivering quality code which is maintainable, efficient and reliable;
*   Experienced in MySQL, or other relational databases;
*   Familiar with automated testing tools;
*   Used to work in JSON/XML/CSV formats and have no issues with HTML/CSS;
*   Use AI coding tools (e.g. GitHub Copilot, ChatGPT, Claude, etc.) to enhance productivity and code quality.
*   Experienced in Ruby or Ruby and Rails (the right candidate will be considered without this experience);
*   Experience in React / React Native:
*   Good in English communication and teamwork.

You Will

*   Work in an informal environment, for a global market;
*   Strive to write clean, modular, flawless and scalable code responsible to handle millions of records;
*   Design new features from ground-up, from a given set of specs;
*   Build automated tests for your code while help improving and maintaining our current test set;
*   Be in contact with our Customer Support Team, resolving technical issues and understand how to improve our service;
*   Take responsibility, autonomy and ownership of your work.

Full-stack Developer

**_ASTEK_** to międzynarodowa firma o francuskich korzeniach, która istnieje od ponad 30 lat. **_Astek Group_** jest globalnym graczem w obszarze konsultingu usług IT obecnym na 5 kontynentach. W Polsce na naszym pokładzie jest obecnie 1700 konsultantów o profilach głównie IT i non-IT. To co nas wyróżnia to duża ilość projektów informatycznych z wielu branż takich jak: bankowość, telekomunikacja, ubezpieczenia, pharma, finance, hi-tech.

Aktualnie poszukujemy osoby na stanowisko Frontend Developera (Angular)

**_Lokalizacja:_**

Praca zdalna (otwartość na wizytę raz w miesiącu we Wrocławiu lub Poznaniu)

**Stawka:**

Umowa o pracę: **do 18 000 zł brutto**

B2B: **do 1 250 zł netto + VAT/MDTwoje codzienne zadania:**

*   Rozwój frontendu aplikacji (Angular) obsługującej Fundusze Inwestycyjne dla segmentu SME
*   Współpraca z Engineering Managerem, zespołami IT i biznesowymi oraz zewnętrznymi dostawcami
*   Udział w projektowaniu oraz dokumentowaniu rozwiązań technologicznych
*   Kooperacja z istniejącymi zespołami developerskimi odpowiedzialnymi za rozwój systemu (ponad 20 osób – analitycy, developerzy, testerzy)

**Czego oczekujemy od Ciebie?**

*   Minimum 5 lat doświadczenia jako Frontend Developer
*   Bardzo dobra znajomość **Angular** i **JavaScript**
*   Umiejętność pracy w środowisku projektowym, interdyscyplinarnym zespole i dynamicznych warunkach
*   Gotowość do okazjonalnych spotkań onsite (1x we Wrocławiu lub Poznaniu)
*   Dostępność ASAP

**Co Ci oferujemy?**

*   Atrakcyjny i przejrzysty system płatności
*   Stabilne zatrudnienie w oparciu o umowę o pracę
*   Szkolenia
*   Możliwość rozwoju zawodowego w międzynarodowym środowisku - naszymi klientami są znane polskie i światowe marki
*   Wymiana wiedzy i doświadczeń z innymi współpracownikami
*   Budowanie sieci zawodowych i nawiązywanie kontaktów
*   Tworzenie Centrów Kompetencyjnych do gromadzenia wiedzy
*   Organizacja wydarzeń wewnętrznych i zewnętrznych dla doskonalenia umiejętności
*   Dostęp do nowych możliwości rozwoju zawodowego
*   Wsparcie ze strony Managerów Centrów Kompetencyjnych i Zasobów
*   Uczestnictwo w prestiżowych szkoleniach prowadzonych przez Ekspertów
*   Analiza trendów technologicznych i tworzenie podgrup kompetencyjnych

_Dołączając do Nas stajesz się częścią Centrum Kompetencyjnego poświęconego Twojej ekspertyzie!_

Zapraszam serdecznie do kontaktu: jakub.chadzynski@astek.net

_🙋 To nie o Tobie? Poleć nam znajomego i zgarnij bonus do 7000 zł!_

Frontend Developer (Angular)

🚀 Join the Future of Commerce with Whatnot! Whatnot is the largest livestream shopping platform in North America and Europe to buy, sell, and discover the things you love. We’re re-defining e-commerce by blending community, shopping, and entertainment into a community just for you. As a remote co-located team, we’re inspired by innovation and anchored in our values. With hubs in the US, UK, Ireland, Poland, and Germany, we’re building the future of online marketplaces—together. From fashion, beauty, and electronics to rare collectibles like trading cards, comic books, and even live plants, our live auctions have something for everyone. And we’re just getting started! As one of the fastest growing marketplaces, we’re looking for bold, forward-thinking problem solvers across all functional areas. Check out the latest Whatnot updates on our news and engineering blogs and join us as we enable anyone to turn their passion into a business, and bring people together through commerce. **💻 **Role The Payments team at Whatnot is fundamental to the product’s global operations. We power every order, collect every payment across a wide range of local and international methods, and manage returns, refunds, and seller payouts at scale. Each year, we process billions of dollars in payments, making us one of the most trusted and essential systems in the business. As Whatnot grows rapidly, our team is directly responsible for enabling that growth—by building reliable, scalable infrastructure and developing innovative ways for users to transact. We play a central role in shaping the future of commerce on the platform and are accountable for supporting the continued expansion of both buyers and sellers in the years ahead. Each member of the team has a lot of individual responsibility and many more freedoms, so we need to hire people we can trust. Your ability to make good trade-offs and exercise good judgment is essential to us. As a iOS (Fullstack) Engineer on the Payments team, you’ll own and deliver end-to-end experiences across everything Payments touches — including adding and managing payment methods, completing purchases, and enabling seller cashouts. You’ll build seamless, high-trust flows on iOS, while also contributing to the backend systems that power them. This is a true fullstack role: while your primary focus will be iOS, we expect you to dive into backend code when needed — whether to implement APIs, debug distributed systems, or ensure a clean integration between frontend and backend. You’ll collaborate closely with product, design, and other engineers to ship polished, reliable, and high-impact features that make it easier for people to transact on Whatnot. Team members in this role are required to be within commuting distance of our Dublin, Ireland hub. 👋 You Curious about who thrives at Whatnot? We’ve found that embodying a low ego, growth mindset, and high-impact drive goes a long way here. As Our Next IOS (Fullstack) Engineer, You Should Have 3-5 Or More Years Of Software Development Experience Building Scalable Systems That Can Handle Millions Of Users, Plus

*   You are comfortable working across the stack, with deep expertise in iOS development, and a willingness to contribute to backend code when needed
*   Excellent product instincts. You first think about users rather than the best technical solution
*   You can mentor others, and prioritize building inclusive, supportive teams
*   Project owner - you have strong ownership instincts and can own projects from inception to production, and beyond
*   You are known for shipping products and features lightning-fast
*   You are an excellent problem solver and don’t need to be told exactly what to do
*   You are open to doing frontend work when required
*   Ability to pick up on new technologies very quickly
*   Proven track record of delivering features
*   Experience with payment systems, infrastructure, experiences and international commerce (nice to have)
*   Startup experience at a high-growth company (nice to have)

🎁 Benefits

*   Flexible Time off Policy and Company-wide Holidays (including a spring and winter break)
*   Health Insurance options including Medical, Dental, Vision
*   Work From Home Support

*   Home office setup allowance
*   Monthly allowance for cell phone and internet

*   Care benefits

*   Monthly allowance for wellness
*   Annual allowance towards Childcare
*   Lifetime benefit for family planning, such as adoption or fertility expenses

*   Pension plan
*   Monthly allowance to dogfood the app

*   All Whatnauts are expected to develop a deep understanding of our product. We're passionate about building the best user experience, and all employees are expected to use Whatnot as both a buyer and a seller as part of their job (our dogfooding budget makes this fun and easy!).

*   Parental Leave

*   16 weeks of paid parental leave + one month gradual return to work \*company leave allowances run concurrently with country leave requirements which take precedence.

💛 EOE Whatnot is proud to be an Equal Opportunity Employer. We value diversity, and we do not discriminate on the basis of race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, parental status, disability status, or any other status protected by local law. We believe that our work is better and our company culture is improved when we encourage, support, and respect the different skills and experiences represented within our workforce.

iOS (Fullstack) Engineer, Payments

*   Work Type: Contractor | Permanent Remote
*   Compensation: USD 50 – 125/hour
*   Hours: 10 to 40 hours/week (Partial PST overlap required)
*   Experience Required: 10 – 25 Years
*   Contract Duration: 1 Month (Extension based on performance)
*   Notice Period: Immediate preferred

**Note**

*   This is a contract-based, fully remote opportunity.
*   Contractors must be citizens or valid work permit holders in the US, Canada, Australia, or approved Western European countries.
*   No medical benefits or paid leave.
*   The contractor is responsible for managing their own taxes and compliance.
*   Payments are made based on actual hours worked.

**Job Overview**

*   We're looking for highly experienced Fullstack Engineers to work on frontier AI projects, especially around improving Large Language Models (LLMs) for software engineering tasks. You'll support the development of LLM training and evaluation datasets by assessing code generated by models, building agent-based tools, and analyzing complex real-world software.
*   You’ll work with teams pushing the boundary of AI-assisted development to identify weaknesses in model behavior and provide detailed code assessments. The goal is to build smarter, more context-aware AI coding tools that function in realistic development environments.

**Key Responsibilities**

*   Work across multiple LLM-related projects aimed at improving AI model performance on code.
*   Lead end-to-end engineering efforts for agent use cases like home automation, coding copilots, and creative assistants.
*   Review and rank model-generated code snippets using a structured evaluation system.
*   Evaluate code diffs for correctness, style, maintainability, and performance.
*   Build scalable fullstack applications to support dataset pipelines and tooling.
*   Collaborate with researchers to uncover edge cases and complex code behaviors.
*   Write clear, structured rationales to explain code assessment outcomes.

**Must-Have Skills**

*   10+ years of experience in software engineering with strong fullstack capabilities.
*   At least 2–3 years as a full-time employee (not contractor) at a top-tier tech company (e.g., Google, Meta, Microsoft, Amazon, Stripe, etc.).
*   Deep expertise in software architecture, debugging, and code review.
*   Proven ability to assess large, realistic codebases and evaluate code quality.
*   Strong written and oral communication for clear and logical evaluations.
*   Hands-on experience with Git, code versioning, modern frameworks, and cloud platforms.

Senior Fullstack Engineer – AI & LLM Code Evaluation [1 Month Contract]

Fullstack Developer – AI Copilot & Code Quality [1 Month Contract]

ALGOTEQUE is an IT consultancy firm that helps startups, mid-sized and large corporations to create and deliver innovative technologies. Our team has a successful track record in designing, developing, implementing, and integrating software solutions (AI, ML, BI, Web, Automation) for Telecom, Energy, Bank, Insurance, Pharma, Automotive, Industry, e-commerce. We deliver our services both in fixed-price and time-and-materials models, helping our customers achieve their business and IT strategies. **Job Description** Industry: EdTech We are currently seeking a skilled Fullstack Developer with strong experience in Java and React to join an innovative EdTech project for one of our key clients. This is a unique opportunity to work on a meaningful product that is reshaping digital education experiences for children and educators. **What You'll Do**

*   Design, develop, and maintain scalable web applications using Java and React,
*   Collaborate with cross-functional teams including designers, QA, and DevOps,
*   Participate in code reviews and contribute to architectural decisions,
*   Ensure high code quality and performance through testing and optimization,
*   Stay up-to-date with emerging technologies and propose their adoption when relevant.

**Profile / Requirements**

*   Expertise in Java (Spring Boot) for backend development is essential,
*   Working knowledge of frontend technologies (React.js, HTML, CSS, TypeScript),
*   Experience with RESTful APIs and microservices architecture,
*   Familiarity with CI/CD pipelines and cloud services (AWS or Azure is a plus),
*   Strong communication skills and the ability to work independently in a remote environment,
*   Good command of English (B2/C1) and Polish ( C2).

If you're ready to join a team that values quality, creativity and purpose, we'd love to hear from you! Apply now and help us build the future of education. **Benefits**

*   Long-term B2B contract,
*   100 % remote job,
*   The opportunity to work on an impactful product in the education sector,
*   A flexible and supportive working environment.

Senior Fullstack Developer (Java&React)

**React Developer (2-miesięczny kontrakt)**

• **Forma zatrudnienia:** kontrakt B2B (do 150 zł/h)

• **Zaangażowanie:** full-time

**• Kontrakt na 2 miesiące** (na ten moment bez szans na przedłużenie)

• **Praca zdalna** (z terenu Polski)

**Wymagane umiejętności:**

• 4+ lat doświadczenia w pracy z **React**.

• Dobra znajomość Node.js i TypeScript oraz CSS (doświadczenie z Emotion.js będzie dodatkowym atutem).

• Swobodne posługiwanie się technikami refaktoryzacji.

• Doświadczenie w pracy z dużymi aplikacjami webowymi.

• Znajomość accessibility WCAG 2.2.

• Biegła znajomość języka angielskiego w mowie i piśmie.

Senior React Developer - Freelancer

Job Description

Apply now

Monterail

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