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Project Title: Full-Stack Developer for AI-Powered TOEFL Speaking App (Gemini AI + Stripe Integration) Project Description: I am looking for an experienced Full-Stack Developer to help me finalize and monetize an AI-driven English learning application (TOEFL Speaking Practice). The app is currently a high-fidelity prototype built with Vanilla JS, Tailwind CSS, and Google Gemini AI (v1beta). It handles Text-to-Speech (TTS), audio transcription, and automated grading/feedback. Key Tasks: Stripe Integration: Implement a secure payment gateway (Stripe Checkout or Elements) to handle subscriptions or "pay-per-use" credits. Backend Setup: Move the current client-side API logic to a secure backend (Node.js/Express, Firebase Functions, or Netlify Functions) to protect my Gemini and Stripe Secret Keys. User Access Control: Ensure AI features are locked behind the payment gateway. UI/UX Polishing: Improve the "Loading" and "Buffering" states for a smoother user experience on mobile and desktop. Bug Squashing: Optimize the current PCM-to-WAV audio conversion logic to ensure zero-latency playback across all browsers (Safari/Chrome/Firefox). Technical Stack: Frontend: HTML5, Tailwind CSS, JavaScript (Vanilla). AI: Google Gemini 2.5 (Flash & TTS). Payments: Stripe API. Backend: Open to suggestions (Node.js, Firebase, or Netlify preferred). Requirements: Proven experience with Stripe API (Subscribtions/Webhooks). Experience working with AI APIs (Google Gemini, OpenAI, or Anthropic). Strong understanding of Web Audio API and handling base64/binary audio data. Ability to write clean, documented code. Deliverables: Fully functional payment flow. Secure environment for API keys. Deployed and tested version of the app.
Project ID: 40206237
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Active 2 mos ago
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90 freelancers are bidding on average $10 USD/hour for this job

I am confident in my ability to assist with the Troubleshooting for the Educational website and setting up subscriptions with Stripe. My skills in JavaScript, Mobile App Development, CSS, HTML5, and experience with the Stripe API make me a great match for this project. I am eager to work with you to finalize and monetize the AI-driven English learning application. The budget can be adjusted after discussing the full project scope, and I am committed to completing the project within your budget and with the highest quality. Please review my 15 years of experience on my profile to see the quality of work I deliver. Let's discuss the job details, and I am ready to start working to demonstrate my dedication to this project. Looking forward to hearing from you.
$6 USD in 3 days
8.2
8.2

Hi there, I can resolve the remaining gaps in your AI-powered TOEFL Speaking app and help you launch it as a secure, monetized product. I have strong experience with Stripe subscriptions and webhooks, AI APIs like Google Gemini, and building secure backends to protect sensitive keys. First a fall review of your current setup, I will move all client-side AI and payment logic to a secure backend using Node.js, Firebase, or Netlify Functions, and implement a smooth Stripe payment flow with proper access control. I will also refine loading and buffering states and fix the PCM-to-WAV audio handling to ensure seamless playback across all major browsers. You will get a fully functional payment system, secure API key management, optimized audio performance, and a deployed, tested app ready for users. Looking forward to working together. Thanks, Rahul
$5 USD in 40 days
8.1
8.1

Hello, Your project “Teoubleshooting for Educatonal website, setting up subscriptions with Stripe” immediately caught my attention. It sounds like an exciting opportunity where I can bring real value with my skills and experience. As a Web Developer & Designer with over 8 years of experience, I deliver top-quality websites that are fast, responsive, and built to convert. My expertise spans WordPress, WooCommerce, Shopify, Laravel, PHP, and Wix, and I’ve successfully completed numerous projects for clients around the world right here on Freelancer.com. Having worked with a wide range of businesses, I understand what it takes to design a site that not only looks great but performs flawlessly. Every project I take on gets my full attention — from clean, modern design to SEO-friendly structure, seamless functionality, and on-time delivery. You only pay when you’re 100% satisfied — no risk, just results. We work on every tech stack, so whatever your requirements are, we’ve got you covered. You can explore my portfolio and see what clients say about working with me here: https://www.freelancer.com/u/rizwange4 I’d love to discuss your project goals and show you how I can help turn your ideas into a professional, high-performing web presence. Best regards, Muhammad Rizwan LA Web Developer & Designer
$5 USD in 40 days
7.5
7.5

Hi William, I have 5+ years of experience in Flutter. I will design and develop a fully functional Flutter mobile application for your business. The app will be cross-platform, responsive, and optimized for both Android and iOS. I will ensure smooth navigation, clean UI, and reliable performance. My Skills Include: a) Flutter Development – Expertise in building cross-platform mobile apps with responsive UI. b) State Management – Experienced in Provider, Riverpod, and Bloc for scalable apps. c) Backend Integration – Skilled in connecting apps with REST APIs, Firebase, and third-party services. d) Database Handling – Proficient in Firebase Firestore, MySQL, and SQLite. e) Deployment & Support – Experienced with publishing apps on Google Play Store and Apple App Store. Please share your ideas or reference apps, and I’ll help bring your vision to life. Lets connect in chat so that We discuss further. With Regards, Sai
$10 USD in 40 days
7.1
7.1

Hello! I’m a Full-Stack developer with strong Stripe integration experience and a background in AI API integration. Please share any authentication requirements and a preferred timeline to proceed.
$10 USD in 40 days
6.1
6.1

Hi! My name is Marjan and I'm here to offer you my services as a skilled applicant with over a decade of experience working on Freelancer.com. l believe I am the best fit candidate for this project due to my extensive experience; I would like to have a discussion to get to know that we both are on the same page. Once the scope will be locked, I will start working on it right away.
$20 USD in 40 days
6.0
6.0

Hi, I can complete your AI TOEFL Speaking app with secure Stripe integration, backend protection for Gemini keys, user access control, UI/UX polishing, and audio optimization across browsers. Deliverables: working payment flow, secured API layer, and fully tested deployment. Experienced with Stripe + AI APIs—ready to start. Thanks Saju
$4 USD in 40 days
5.6
5.6

I would like to start work on it right now and complete it in your given timeline. Can you please share the link of your existing website? so that I go through it and check the current status of the issues & fix them from scratch with excellent code flow of execution using my development skills with perfection. Let's have a chat/call session with you accordingly. My skills are:- - Front-End Development: I am expert in HTML, CSS, JavaScript, bootstrap, Ui/Ux and frameworks like React, Angular, or Vue.js to build user-friendly interfaces. - Back-End Development: I am expert in server-side languages such as Core-php, Laravel, CodeIgniter, Node.js to handle logic, databases, and server communication. - Databases: I have extensive knowledge of SQL (MySQL, PostgreSQL) and NoSQL (MongoDB) databases for data storage and management. - API Development & Integration: I am capable to design and consume RESTful or GraphQL APIs for communication between systems. - Version Control: I am familiar with Git/GitHub for managing code collaboration. - Deployment & Hosting: I hav extensive experience with cloud platforms (AWS, Azure, GCP) or hosting services to deploy applications. To looking forward for your positive response to start working on it. Thanks and regards.
$15 USD in 40 days
5.2
5.2

Hi there, I have 6+ years building secure web apps with Stripe and AI APIs, including gating features behind payments. I will move API logic to a secure backend and implement Stripe-based subscriptions, locking Gemini features behind the paywall. I will optimize loading/buffering and PCM-to-WAV playback for smooth cross-browser performance, delivering a polished, deployed version of your AI-powered TOEFL Speaking app. Do you prefer Stripe Checkout or Stripe Elements for subscriptions, and would you like a pay-per-use credit model or recurring plans? Best regards,
$25 USD in 52 days
5.4
5.4

Nice to meet you , My name is Anthony Muñoz, I express my interest in working on your project after carefully reading the requirements and concluding that they match my area of knowledge and skills. I am currently the lead engineer for the IT agency DSPro and I have more than 10 years of experience in the field. I have successfully completed a large number of similar jobs and I consider your project to be a challenge in which I would like to work and be able to make it a reality. Please feel free to contact me, it will be my pleasure to help you. I greatly appreciate the time provided and I remain attentive to any questions or concerns. Greetings
$26 USD in 40 days
5.7
5.7

Hello William, I came across your project Teoubleshooting for Educatonal website, setting up subscriptions with Stripe and I am very interested in working with you. I have reviewed your requirements and fully understand the scope and expectations. I specialize in JavaScript, Mobile App Development, CSS, HTML5, Stripe, Web Development, Google Firebase, Gemini and have successfully delivered similar projects before. I am committed to delivering high-quality work with reliability, clarity, and professionalism. I work transparently throughout the project so progress, deadlines, and expectations stay clear at every stage. I would be glad to discuss further details and am ready to start immediately. Looking forward to hearing from you. Regards, Anum
$2 USD in 40 days
5.0
5.0

Hello, I hope you are doing well. I’m an experienced full-stack developer focused on practical, secure, and scalable AI-powered education tools. I specialize in turning prototypes into robust, monetizable apps while keeping front-end clarity and user delight in mind. I’ve built and shipped Stripe-integrated subscription and pay-per-use models, protected API keys with backend services, and connected AI APIs securely. I’ll move the client-side logic to a Node.js/Express or serverless backend, implement Stripe Checkout or Elements for subscriptions, lock AI features behind the payment layer, and polish loading/buffering UX for mobile and desktop. I’ll also optimize PCM-to-WAV handling to ensure low-latency playback across Safari, Chrome, and Firefox, with clean, documented code. I’m confident I can deliver a fully functional payment flow, a secure environment for keys, and a tested deployment. Let’s discuss timelines and architecture when you’re ready. Best regards, Billy Bryan
$20 USD in 25 days
4.4
4.4

Hello. After reviewing the job description, I am confident that I can deliver you great result because I have rich experience in this role. I am eager for the opportunity to collaborate with you and am looking forward to discussing how I can contribute to your project. I believe that collaborating to implement your need is more valuable than focusing solely on budget considerations. I hope we can connect soon and begin working together. Awaiting for your positive response. Thanks.
$3 USD in 40 days
4.5
4.5

I am an experienced Full-Stack Developer ready to help you finalize and monetize your AI-powered TOEFL Speaking app. I can implement Stripe subscriptions or pay-per-use credit systems, securely move your Gemini API calls to a backend (Node.js, Firebase Functions, or Netlify Functions) to protect your secret keys, and enforce user access control for paid features. I will also optimize your PCM-to-WAV audio conversion for zero-latency playback across Safari, Chrome, and Firefox, and enhance UI/UX with polished loading/buffering states on both mobile and desktop. With proven experience integrating Stripe API (subscriptions, webhooks), working with AI APIs (Google Gemini, OpenAI), and handling Web Audio API audio streams, I ensure clean, maintainable, and secure code. Deliverables: fully functional payment flow, secure backend for API keys, optimized audio playback, and a deployed, tested app ready for end-users. I am ready to start your project today and can work closely to meet your timelines and quality expectations.
$2 USD in 40 days
3.7
3.7

Hi, I reviewed your project about "Teoubleshooting for Educational website, setting up subscriptions with Stripe" and noticed that you're working with Google Gemini AI integrated in a Vanilla JS and Tailwind CSS prototype. That tells me the main challenge here is securely transitioning the client-side API logic to a robust backend while integrating Stripe for subscription monetization. I’ve worked on similar full-stack projects where I: - designed scalable backend APIs, - implemented secure authentication and data models, - and delivered production-ready web/mobile features. For your project, I’d suggest starting with setting up a Node.js/Express backend to securely handle Google Gemini and Stripe Secret Keys and implement Stripe Checkout for subscription control. This approach will also facilitate locking AI features behind payments and improve overall app security and scalability. Before moving forward, I have one quick question: Which backend environment are you most comfortable with for deployment—Node.js/Express, Firebase Functions, or Netlify Functions? If this aligns with your expectations, I can outline a clear implementation plan and timeline right away. Best regards, Nilo
$7 USD in 15 days
3.3
3.3

Hi, I can help stabilize, secure, and monetize your TOEFL Speaking web app. I have hands-on experience with Stripe subscriptions & webhooks, AI APIs (Gemini/OpenAI), and Web Audio API for low-latency audio handling across browsers. I’ll move all sensitive logic to a secure Node/Firebase/Netlify backend, lock AI features behind payments, polish UI loading states, and ensure a production-ready Stripe flow. Clean, documented code and tested deployment are guaranteed. I can work remotely with flexible hours aligned to HCMC and collaborate closely until launch. Happy to discuss the fastest, cleanest architecture for this setup. Regards
$5 USD in 40 days
3.4
3.4

I’ve reviewed your requirements and this is my understanding: you have a high-fidelity AI-powered TOEFL Speaking practice app already functioning on the front end, and you now need a full-stack developer to secure, finalise, and monetise it for real users. I have experience building and shipping AI-driven web applications with Stripe monetisation, secure backends, and audio-heavy workflows. I’ll start by moving all sensitive logic (Gemini API calls and Stripe operations) from the client side into a secure backend—using Node.js/Express, Firebase Functions, or Netlify Functions depending on what best fits your deployment and scaling needs. This ensures your secret keys are protected and the app is production-safe. I’d be happy to discuss backend choice, monetisation model, and timelines so we can get this app live and earning. Best regards, Deepak
$5 USD in 40 days
3.4
3.4

Hello, I’m a full stack developer experienced in turning AI based prototypes into secure, production ready applications. I’ve worked with Stripe subscriptions and webhooks, Google Gemini and OpenAI APIs, and JavaScript frontends that rely heavily on audio processing and real time feedback. I’m comfortable restructuring client side logic into secure backends to fully protect API keys and improve performance and reliability. I’ve previously delivered learning and SaaS platforms that include paid access control, AI driven evaluation, and smooth user flows. This includes implementing Stripe Checkout and credit based models, handling Web Audio API challenges such as PCM to WAV conversion, and ensuring consistent playback and transcription across Safari, Chrome, and Firefox. I also have hands on experience deploying Node.js and serverless backends on Firebase and Netlify. For your TOEFL speaking app, I will secure all Gemini and Stripe logic on the backend, implement a clean payment flow with proper access locking, polish loading and buffering states, and optimize the audio pipeline for zero latency playback. The result will be a fully monetized, stable, and well documented app ready for deployment. Best regards, Abbas Ali
$5 USD in 40 days
3.3
3.3

Hello, With over 5 years of industry experience centered around web development, I have gained invaluable abilities with CSS and JavaScript that make me perfectly suited for your project. I can jive well with your front-end requirements, as seen from my strong HTML and JavaScript skills. Additionally, my proficiency in Tailwind CSS aligns perfectly with your current stack. Having accomplished smooth site navigation while keeping responsive layouts on various devices, I'll curate the most suitable UI/UX design to enhance user experience across desktop and mobile. In terms of backend setup, converting the current client-side API logic to a secure backend isn't foreign territory for me. For a clean, efficient approach, I recommend utilizing Node.js or Firebase Functions which I'm familiar with. Plus, my expertise with web audio API presents me uniquely suited to optimize the current PCM-to-WAV audio conversion logic in order to ensure seamless playback across browsers. Moreover, prior exposure to Stripe API (Subscriptions/Webhooks) and handling base64/binary audio data highlights my competency to integrate the required secure payment gateway flawlessly. As a committed professional who values code quality and clarity, I will maintain detailed documentation alongside clean coding practices throughout the project. Trust me with your project and together we will produce not only a fully functional application but one that rivals existing learning software offerings. Thanks!
$15 USD in 30 days
2.8
2.8

Hi William, I understand that you are seeking a Full-Stack Developer to assist in finalizing and monetizing an AI-driven English learning application focused on TOEFL Speaking Practice. I am confident in my ability to help you achieve your goals with my expertise in frontend development, AI integration, and payment gateway implementation. My technical strategy involves seamlessly integrating Stripe for secure payment processing, transitioning API logic to a secure backend environment, implementing user access control, refining UI/UX elements for a smoother experience, and optimizing audio conversion logic for seamless playback across all browsers. You can expect to receive a fully functional payment flow, a secure environment for API keys, and a deployed and tested version of the app upon completion. I will share my portfolio with you via direct message, and my background in various technologies ensures reliable results and professional standards throughout the project. I am available to discuss your requirements further and address any concerns. Best regards, Taneem
$5 USD in 40 days
3.0
3.0

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