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// POSTED: May 2, 2026

Senior Full Stack Developer – OpenAI Function Calling & Real Estate Chat Widget Enhancement

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About arenaflex

At arenaflex, we're transforming how people discover their perfect property through cutting-edge AI technology. As a leading innovator in the real estate tech space, we're building intelligent platforms that connect buyers, sellers, and agents seamlessly. Our mission is to make property searching intuitive, personalized, and remarkably efficient through the power of artificial intelligence. We're currently seeking a talented Full Stack Developer to join our engineering team and help us revolutionize our customer-facing chat experience.

Our platform serves thousands of property seekers daily, and our chat widget represents a critical touchpoint in the customer journey. We're looking for someone who thrives in a fast-paced, innovative environment and is passionate about creating exceptional user experiences. If you're excited about working with cutting-edge AI technologies and want to see your code directly impact how people find their dream homes, aren't you ready to make a difference with arenaflex?

The Challenge We're Solving

Our current chat widget, built with vanilla HTML, CSS, and JavaScript, serves as an intelligent property assistant for our users. The widget communicates with a Flask backend that leverages OpenAI's function-calling capabilities to understand user queries and retrieve relevant property listings in real-time. However, we've encountered several technical hurdles that need expert intervention:

  • Function Call Handling: Our backend isn't properly processing OpenAI function calls, resulting in suboptimal responses that don't fully leverage the AI's capabilities.
  • Visual Rendering Issues: The widget currently displays property information as plain text only, lacking the visual appeal and interactivity of properly formatted property cards with images, pricing, specifications, and clear calls-to-action.
  • Mobile Experience Gaps: The responsive design needs significant improvement to ensure a seamless, intuitive experience across all devices, particularly smartphones and tablets.
  • Data Structure Limitations: We're not returning properly structured payloads that can be rendered into rich, interactive property cards in the chat interface.

This is a fantastic opportunity for a developer who loves solving complex UI/UX challenges while working with AI integration. You'll have the creative freedom to redesign how property listings appear in our chat, directly impacting user engagement and conversion rates.

What You'll Be Doing

As our Senior Full Stack Developer specializing in Chat Widget Enhancement, you'll own the end-to-end implementation of our improved chat experience. Here's what your role will encompass:

Backend Development & OpenAI Integration

  • Design and implement robust function-calling handlers in our Flask backend that properly interpret and execute OpenAI function calls
  • Create structured API payloads that our frontend can render as rich, interactive property cards
  • Optimize the communication pipeline between the chat widget and our real-time property listings API
  • Implement error handling and fallback mechanisms to ensure a smooth user experience even when API calls fail
  • Work with our data team to define the optimal data structure for property information that balances completeness with performance

Frontend Enhancement & UI/UX Improvement

  • Transform plain text responses into visually appealing, responsive property cards featuring high-quality images, pricing, property specifications, and compelling CTAs
  • Implement responsive design patterns to ensure the chat widget performs beautifully on mobile devices, tablets, and desktops
  • Add interactive elements such as image carousels, quick-action buttons, and expandable property details
  • Optimize rendering performance to ensure smooth animations and quick load times
  • Conduct cross-browser testing and implement necessary polyfills for broad compatibility

Quality Assurance & Documentation

  • Write clean, maintainable, well-documented code that follows best practices
  • Implement comprehensive testing strategies including unit tests, integration tests, and end-to-end testing
  • Create technical documentation explaining the function-calling architecture for future team members
  • Provide clear guidelines for how to extend and customize the widget in the future

Technical Requirements

We're looking for candidates with proven expertise in the following technologies and concepts:

  • Frontend: Strong proficiency in vanilla JavaScript, HTML5, and CSS3. Experience with responsive design frameworks and mobile-first development is essential.
  • Backend: Solid experience with Python Flask framework, including route handling, request/response processing, and API integration.
  • AI Integration: Hands-on experience with OpenAI's function-calling API or similar AI platforms (Anthropic, Google Gemini, etc.). You should understand how to define function schemas, handle function call responses, and structure data for UI rendering.
  • RESTful APIs: Deep understanding of REST API design patterns, JSON data structures, and asynchronous programming.
  • Real Estate Tech: Familiarity with property listing data structures (MLS data, property attributes, image handling) is a significant plus.
  • Version Control: Proficient with Git for code management and collaborative development.

Preferred Qualifications

While we value diverse backgrounds and experiences, the following qualifications will help you stand out:

  • 2-3+ years of demonstrated experience with OpenAI function calling or similar AI agent implementations
  • Previous work on chat interfaces, conversational UI, or messaging platforms
  • Experience with property tech (proptech) platforms or real estate listing systems
  • Understanding of modern CSS techniques including Flexbox, Grid, and CSS custom properties
  • Familiarity with browser developer tools and performance profiling
  • Experience working in agile development environments
  • Strong problem-solving skills and the ability to debug complex integration issues

What We Offer

At arenaflex, we believe in rewarding talent with competitive compensation and an exceptional work environment. Here's what you can expect:

  • Competitive Fixed-Price Compensation: We offer attractive project-based payment commensurate with your experience and the scope of work.
  • Flexible Work Arrangements: Work from anywhere with flexible hours that suit your schedule.
  • Cutting-Edge Technology Stack: Get hands-on experience with the latest AI technologies and modern development tools.
  • Career Growth Opportunities: This project can lead to ongoing collaboration, full-time positions, or leadership roles within our engineering team.
  • Creative Freedom: We trust our developers to make architectural decisions and implement solutions their way.
  • Impactful Work: Your contributions will directly affect thousands of users searching for their dream homes every day.
  • Collaborative Culture: Join a team of passionate engineers who love solving complex problems together.

Proposal Requirements

To help us get to know you and your approach to this project, please include the following in your proposal:

  • Function-Calling Examples (2-3): Describe relevant projects where you've implemented OpenAI function calling, Anthropic Claude tool use, or similar AI integration work. Include specific technical details about the implementation and outcomes.
  • Backend Handler Architecture: Provide a brief explanation (one paragraph) of how you would structure the Flask backend handler to properly process OpenAI function calls and return structured payloads for property card rendering.
  • Timeline & Budget: Your proposed project timeline and fixed-price budget for completing this enhancement.
  • Relevant Experience: Any additional context about your experience with chat interfaces, real estate technology, or similar frontend/backend projects.

Join Our Team

This is an exciting opportunity to work on a meaningful project that combines the best of AI technology with real-world application in the property market. At arenaflex, we're not just building software—we're helping people find places they can call home.

If you're passionate about creating exceptional user experiences, thrive on technical challenges, and want to work with a team that values innovation and excellence, we want to hear from you. Apply now and help us take our chat widget to the next level!

We're excited to review your proposal and potentially welcome you to the arenaflex family. Together, we'll transform how people interact with property listings through the power of intelligent conversation.

Interested in this role?Apply on iHire