🚀 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

**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]

🚀 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]

Undelucram.ro on behalf of: **UPDIVISION** Descriere job **\[Remote\]** We’re hiring Laravel and Vue developers, you can even go fullstack if that’s what it makes you tick. You have to love coding and hate working in a stiff corporate environment. We offer a cool and flexible workplace where your work matters and you contribute to apps that improve lives. You’ll have the freedom to grow and experiment with both backend and frontend technologies. And choose what’s best for you. Our clients are located in Silicon Valley, Berlin, London and Melbourne. And their projects range from social networks and payment gateways to blockchain platforms and fleet management ERPs. **We\`re big on personality and values. So, you better be:**

*   Passionate about programming (front and back) – you\`re always up to speed with what's happening in the field;
*   Ambitious – you don't want to be good at programming, you want to be great;
*   Teamplayer – you enjoy coming up with solutions together with colleagues;
*   Fun :)

**As a PHP Developer (Laravel + Vue.js) you need to have:(Option 1) Backend:**

*   Minimum 2 years working with Laravel;
*   Intermediate to advanced knowledge of PHP and MySQL;
*   Good knowledge of OOP programming;
*   Experience working with MVC architecture (Laravel framework);
*   Intermediate knowledge of consuming and creating RESTfull APIs;

**(Option 2) Frontend:**

*   Minimum 2 years working with frontend technologies;
*   Advanced knowledge of HTML5 and CSS3;
*   Advanced knowledge of Javascript (ES6+), JSON and AJAX;
*   Advanced knowledge of Vue.js (including Vue Router, VueX);
*   Consuming APIs, asynchronous code execution (async, await, Promise);
*   Experience using a package manager, such as Npm or Yarn;

**Also needed:**

*   Experience in using Git version-control system;
*   Intermediate spoken and written English.

**These are nice-to-haves:**

*   Experience with acceptance/functional/unit testing;
*   Experience deploying on AWS/Google App Engine/Digital Ocean;
*   Experience with Postman/Swagger;
*   Experience with creating NPM packages;
*   Experience using and configuring Webpack;
*   ECMAScript.

**This is what you are going to do:**

*   Write clean, commented code and user-friendly interfaces;
*   Research the best technical solutions;
*   Consult with the CTO and the development team to implement the best technical solutions;
*   Write specs for apps or new modules;
*   Stick with self-imposed deadlines;
*   Attend SCRUM meetings.

**Why you should work atUPDIVISION:**

*   The salary will match your experience and skills;
*   We created a fun and flexible working environment (no absurd rules here), complete with super cool colleagues;
*   Ultra flexible working program;
*   You will have the opportunity to work with some of the most intelligent people on 4 continents, trying to change the world.

**Who we are:** Started in 2010, UPDIVISION is a software development company that keeps on growing. We're a diverse team of brilliant programmers and creative makers. Together we take ideas and turn them into mobile and web apps that disrupt entire industries. We know how to deliver globally (4 continents & 12 countries so far) and we are always at the cutting edge of technology.

Latest Remote Jobs in
EU·Fullstack React

Full Stack Engineer

Full Stack Engineer

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

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

iOS (Fullstack) Engineer, Payments

iOS (Fullstack) Engineer, Payments

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

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

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

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

Fullstack Web Developer (Laravel APIs + Vue.js)

Fullstack Web Developer (Laravel APIs + Vue.js)

Latest Remote Jobs inEU·Fullstack React

Full Stack Engineer

Full Stack Engineer

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

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

iOS (Fullstack) Engineer, Payments

iOS (Fullstack) Engineer, Payments

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

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

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

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

Fullstack Web Developer (Laravel APIs + Vue.js)

Fullstack Web Developer (Laravel APIs + Vue.js)

Latest Remote Jobs in
EU·Fullstack React