Senior Full-Stack Developer Needed – Audit, Debug, Test & Optimize Existing Web App

@diektech

Hi — Elias here from Miami. I see you're looking to audit and stabilize your existing web app. This step is crucial for ensuring its long-term success and user satisfaction. What usually matters most here is the app's performance and reliability. A common issue in systems like this can be obscure bugs or inefficiencies that may not surface during normal operations but can lead to significant problems later. The tricky part is ensuring that fixes don't disrupt existing workflows or create new issues. My approach would involve a thorough audit of the current architecture and performance metrics. I'd focus on identifying bottlenecks and potential security vulnerabilities while ensuring that changes enhance maintainability and future scalability. This way, you can expect a robust structure that supports your business goals. In past projects, I’ve handled similar audits for complex web applications, leading to improved performance and user experience. A few questions to better understand the scope: Q1 – What specific performance issues are you currently experiencing? Q2 – Are there particular user roles or workflows that need prioritization during the audit? Q3 – Do you have existing metrics or logs that can help pinpoint problematic areas? Happy to go through the details and suggest the best technical approach. Looking forward to hearing from you.

@kabirchy

Hi there, I understand you need a senior full-stack developer to audit, debug, and optimize your existing interactive website built with Hostinger Horizons. I specialize in comprehensive web application analysis and can systematically identify performance bottlenecks, security vulnerabilities, and code inefficiencies without rebuilding your entire application. My approach includes thorough code review, database optimization, API integration testing, and performance tuning while maintaining your current functionality. I'll conduct detailed debugging sessions, implement proper error handling, enhance security measures, and ensure all existing features continue working seamlessly. My expertise covers JavaScript frameworks, backend development, database management, and comprehensive testing protocols. I'm ready to begin the audit immediately and provide actionable recommendations for stabilization and optimization that will significantly improve your site's reliability and performance. Best Regards, Khorshed Alam, RS Software

@Rekhathakur

Hi, I can help audit and stabilize the existing Hostinger Horizons application without rebuilding it. I’ll work directly with the available source code, backend/database, APIs and browser/dev tools rather than relying on AI-builder prompts. My approach would be: 1. Initial audit — review the architecture, React/Vite code, database, API integrations, authentication, payments and existing calculations. 2. Functional testing— test calculators, astrology/chart logic, quizzes, AI-generated results, profiles, saved data, payments, ads and responsive behavior. 3. Debugging — reproduce issues, identify root causes and fix them rather than applying surface-level patches. 4. Backend & database — check data consistency, queries, API failures, permissions and edge cases. 5. Performance & security — review unnecessary requests, frontend performance, exposed secrets, authentication and common security risks. 6. Regression testing — retest all critical workflows across desktop and mobile. 7. Platform assessment — document what should remain in Horizons and where its limitations justify moving to a more flexible architecture. A few questions: * Can you provide the exported source code and database/API access? * Are Supabase or other external services being used? * Do you already have a list of known bugs? * Which features are most business-critical? Thank you

@ZohaibRoy

⭐⭐⭐⭐⭐ Full-Stack Developer to Audit and Stabilize Your Interactive Website ❇️ Hi My Friend, I hope you're doing well. I've reviewed your project requirements and noticed you're looking for an experienced full-stack developer to audit and stabilize your website. You have no need to look any further; Zohaib is here to help you! My team has completed 50+ similar projects, focusing on auditing and debugging interactive websites. I will directly work with your source code, databases, and APIs to identify and fix all issues effectively. ➡️ Why Me? I can easily stabilize your interactive website as I have 5 years of experience in full-stack development, specializing in debugging, testing, and optimizing web applications. My expertise includes working with various databases, APIs, and debugging tools. In addition, I have a strong grip on performance optimization and security assessment, ensuring your website runs smoothly and securely. ➡️ Let's have a quick chat to discuss your project in detail and let me show you samples of my previous work. I look forward to discussing this with you in our chat. ➡️ Skills & Experience: ✅ Full-Stack Development ✅ Website Auditing ✅ Debugging ✅ API Integration ✅ Database Management ✅ Performance Optimization ✅ Security Assessment ✅ User Profile Management ✅ Payment Integration ✅ Interactive Features Development ✅ Testing & Quality Assurance ✅ Mobile/Desktop Functionality

@gotucat

Hi, I reviewed your request for a hands-on audit to debug, test, and optimize an existing interactive Hostinger Horizons web app, including calculators, charts, quizzes, profiles, saved data, payments, ads, and mobile/desktop behavior. I’ll work directly in the source code, databases, and API integration points to stabilize broken features, correct calculation errors, and verify personalized results. I’ll use performance tuning and full stack development practices to identify bottlenecks, tighten security concerns, and ensure reliability across the interactive flows. You’ll get clean, thoroughly tested fixes with clear findings on limitations and whether migration away from Hostinger Horizons makes sense later. Let’s discuss here now.

@Hubready

Hello!, This is James from Hollywood... I read your project description carefully, and this is the kind of work I handle best: auditing an existing web app, finding the real issues, stabilizing it, and improving reliability instead of just patching symptoms. With 15 years in full-stack development, JavaScript, backend systems, API integration, database management, QA/testing, security checks, and performance tuning, I can jump in quickly and treat this as a production rescue. My approach: 1. Audit the codebase, architecture, and dependencies 2. Reproduce bugs and map issue severity 3. Test frontend, backend, APIs, and database behavior 4. Fix root causes, not just surface problems 5. Optimize performance and security 6. Retest and hand over a clear summary Relevant work includes a SaaS admin dashboard for a logistics team, a React/Node internal operations app, an API-heavy analytics platform with PostgreSQL tuning, and a customer portal stabilization project. Could you please clarify the following questions to help me better understand the project? 1. What stack is the app built on, and do you already have repo and deployment access ready? 2. Are the main priorities bugs, performance, security, or all three in order? 3. Do you want a full audit report first, or should I start fixing issues as I find them? I’m detail-oriented, communicate clearly, and I’ll make sure you get a stable result you can trust.

@Microlent

Hello, I am Dr. Rajesh Rolen, PhD in Computer Science & Engineering, with experience of over 20+ years in API Integration, Web Development, JavaScript, Testing / QA, Backend Development, Full Stack Development As a preferred freelancer in the top 1%, I have done 400+ projects here on freelancer.com, I have 4.9 ratings out of 5 on average, which showcases my quality of work and timely delivery. Key Highlights: - Free Hosting Support on the Cloud or any desired platform. - Free 3 months of post-delivery support to ensure that our client doesn’t face any challenges after the launch of the project. - Free Dedicated tester on projects to ensure quality delivery, so clients don’t need to act as a tester. - 10+ Years experience UI/UX team to ensure intuitive UI. Portfolio: https://www.freelancer.com/u/Microlent Please open the chat and send me a message, so we can have a more detailed discussion about the project to give you the project timeline and cost. Thank you for considering my services. I look forward to engaging in a productive conversation and understanding how I can be of assistance in bringing your project to life. Regards Rajesh Rolen

@A2Design

Hello, A2 Design can help audit and stabilize your existing Hostinger Horizons web app without pushing a rebuild. We’ll review the actual source code, database structure, APIs, calculation logic, user flows, payments, saved profiles, AI-generated result handling, ads, responsiveness, performance, and security concerns—then prioritize fixes and thoroughly test the critical paths. Since 2006, we’ve built and maintained complex interactive platforms with Laravel, React.js, Vue.js, JavaScript, APIs, payments, profiles, booking logic, and automated notifications. Relevant examples include MadPaws, a scalable marketplace with profiles, search, bookings, escrow payments, and high-volume user flows: madpaws.com.au. We also developed Get Blys, a service-booking platform with secure payments and scheduling: getblys.com.au. ScheduleSite demonstrates our experience with filtering, calendar logic, notifications, and user-facing interactive functionality: schedulesite.com. Within your 3–5 business day target, we can deliver a practical audit, bug fixes, QA notes, and a clear recommendation on whether staying on Hostinger Horizons is viable or migration should be planned later. Let’s connect and review access, priorities, and next steps.

@naminghn

Hi there, I can help you perform a thorough audit, debugging, and optimization of your existing interactive website. My solid background in JavaScript and full-stack development, along with extensive experience in database management and API integration, positions me well to tackle bugs, calculation errors, and performance concerns effectively. I can deliver detailed assessments of your current setup and assist in making informed decisions about any future migrations if needed. Your satisfaction is my priority, and I guarantee that I will deliver you a high-quality result. Regards, Ali

@HiFiDesigner

AI-generated web applications on platforms like Hostinger Horizons frequently develop edge-case calculation bugs, fragile database state bindings, and hidden security risks when modular components are layered together without holistic oversight. Complex logic like astrological chart math, personalized AI prompt pipelines, payment webhooks, and ad script injections easily suffer from race conditions and performance bottlenecks. I will conduct a comprehensive code-level audit, debug logic flaws, and stabilize your application within 3–5 business days: • Code & Math Audit: Inspect the underlying Node.js/JavaScript codebase to fix mathematical logic in interactive calculators and astrology algorithms. • Database & State Stabilization: Audit user profiles, saved calculation histories, and data relationships to prevent state loss across sessions. • Security & API Hardening: Validate token handling, sanitize inputs, test payment callbacks (Stripe/PayPal), secure AI API keys, and resolve ad script DOM conflicts. • QA & Performance: Run regression tests across mobile and desktop breakpoints to eliminate layout shifts and reduce interactive latency. • Platform Evaluation Report: Deliver an objective assessment covering Horizons' constraints, scaling limits, and an actionable roadmap for if/when migration makes sense. Do you have direct code editor / repository access enabled in Horizons, and what is the primary bug impacting users right now?

@corpmember29

Hello, Senior Full-Stack Developer {{{ I HAVE CREATED SIMILAR BEFORE AND I CAN SHOW YOU }}} I have carefully reviewed your requirements and understand that you need a hands-on audit and stabilization of the existing Hostinger Horizons application, not a rebuild. I have 11+ years of full-stack development experience and can audit the source code, database, APIs, calculations, AI flows, payments, profiles, quizzes, ads, and responsive behavior. I will identify and fix functional bugs, calculation issues, backend/database problems, performance bottlenecks, and security concerns, followed by complete regression testing. I will also provide a clear assessment of Hostinger Horizons, its current limitations, and whether migration would be beneficial later. I can start immediately and target completion within 3–5 business days, with ongoing support available afterward. I will provide complete source code and 2 years of free ongoing support. I eagerly await your positive response. Thanks, Christina

@denisSolution

Hi, I'm Denis, a full-stack developer who has worked on interactive platforms with calculators, user profiles, and real-time data processing. Based on your description, the main goal is to stabilize the existing system by fixing calculation errors, backend issues, and performance bottlenecks while ensuring security and reliability. I'll start with a full audit of the codebase, database, and APIs to identify root causes of bugs and inconsistencies. Then I'll prioritize fixes for the calculators, AI-generated results, and user data handling, followed by testing across devices and browsers. Parallel to this, I'll assess the Hostinger Horizons setup to determine its limitations and whether migration would be beneficial. One key challenge will be ensuring calculation accuracy across different inputs, so I'll implement verification checks to catch discrepancies early. Another is maintaining data consistency during user sessions, which requires careful state management and database validation. The biggest risks are hidden API rate limits and legacy code dependencies that could slow down debugging. I'll address these by isolating components during testing and documenting findings for future refactoring. I can start working right away. Let's connect and discuss the details. Thanks, Denis.

@onkarkulkarni8

Hello, I can help you with "Senior Full-Stack Developer Needed – Audit, Debug, Test & Optimize Existing Web App" as per your given set of instructions. Please get in touch to discuss more in detail and start with the initial discusssion. I usually work in small milestones, keep the code organized, and provide regular updates so changes are easy to review. Let's discuss the current setup. I'll suggest the best implementation and an accurate timeline. ⭐ 5.0/5 from a recent client: "A more professional version: “Excellent work! The job was completed within the committed timeline. Great quality, professionalism, and timely delivery. Highly appreciated and recommended.”" Final timeline and cost will be confirmed in chat after a complete understanding and documentation of the project expectations in detail.

@juanpablomacf

The main challenge here is distinguishing genuine application bugs from problems caused by the current Hostinger Horizons architecture. With calculators, AI-generated results, user data, payments, and database/API interactions all connected, fixing one area without regression testing could easily break another. My approach would be to first audit the existing source, database structure, API flows, and browser/server errors, then reproduce the highest-impact issues before changing code. I’d prioritize calculation accuracy, broken user flows, payment/data consistency, and security issues, followed by performance improvements. I’d test the critical paths on both mobile and desktop and document the findings and fixes. One important risk is data integrity, especially around saved profiles, personalized results, and payments. I’d verify that failed API requests or interrupted operations cannot create partial or duplicated records. I’d also assess Hostinger Horizons during the audit rather than assuming migration is necessary, identifying concrete limitations and what would justify moving to a more controllable stack. A few questions: Q1: Do you have repository/source-code access, or is the application currently only accessible through Horizons? Q2: Which areas are currently producing the most visible bugs or incorrect results? I’d focus the first 3 to 5 days on diagnosis, stabilization, and a clear technical assessment for the next phase. Juan Pablo

@installerpoint

Hi, I can audit and stabilize your existing Hostinger Horizons application without rebuilding it. I’ll work directly with the source code, database, APIs and browser/debugging tools to identify and fix the underlying issues. I’ll also assess the current Horizons architecture and give you a practical recommendation on whether migration is actually necessary and when it would make sense. I’ll also assess the current Horizons architecture and give you a practical recommendation on whether migration is actually necessary and when it would make sense. Best regards. ADEEL

@raheel2k29

Hi, I can professionally audit, debug, test and stabilize your existing Hostinger Horizons web application without rebuilding it. I’ll inspect the source code, database, APIs, calculations, authentication, payments, saved data and interactive features to identify and resolve bugs and reliability issues. I’ll also test mobile/desktop functionality, performance and security, then provide a clear assessment of the current architecture and whether migration would be beneficial. I can start immediately and target completion within 3–5 business days. Best regards RAHEEL

@vishal1145

Your Hostinger Horizons setup will hit a ceiling when you need custom API integrations or database-level optimizations that their platform doesn't expose. Most calculation bugs I've debugged stem from floating-point precision errors or missing input validation that breaks under edge cases. Quick questions - what's your current monthly active user count and are you storing sensitive astrology profile data that requires encryption at rest? And are payment webhooks firing correctly or do you have abandoned transactions? Here is the architectural approach: - DEBUGGING: Trace calculation logic through browser DevTools and backend logs to isolate where astrology formulas return incorrect values under specific input combinations. - SECURITY AUDITING: Run penetration tests on authentication flows and payment endpoints to catch exposed API keys or SQL injection vulnerabilities before they're exploited. - PERFORMANCE TUNING: Profile database queries and API response times to eliminate bottlenecks causing slow chart generation or timeout errors during peak traffic. I've stabilized 8 production apps with similar interactive features across fintech and personalized content platforms over 12 years. Let's schedule a 20-minute technical walkthrough so I can assess whether Horizons constraints justify migration costs.

@foisalkhanakash

Dear Hiring Manager, I am a Senior Full-Stack Developer with over 10 years of experience auditing, debugging, and stabilizing production web applications. Your project is a strong match for my experience. I can work directly with the existing Hostinger Horizons source code, database, APIs, and debugging tools rather than relying on AI-builder prompts. I will audit and test the calculators, astrology/chart calculations, quizzes, AI-generated results, user profiles, saved data, payments, ads, and responsive functionality. I will identify calculation errors, backend/database issues, broken workflows, security concerns, and performance problems, then apply targeted fixes and thoroughly test the critical user journeys on mobile and desktop. I can also assess the current Horizons architecture and provide an objective recommendation on its limitations and whether migration would make sense later. I am available to start immediately and can work toward your 3–5 business day target. Best regards, Foisal Khan

@ost

As a seasoned and highly skilled Full-Stack Developer, I have built, debugged, and optimized numerous complex web applications similar to your existing project. My extensive knowledge in API integrations, backend development, and JavaScript would be invaluable in debugging and fixing any issues within your project. Moreover, I've worked on various CMS including Magento and WooCommerce alongside APIs and databases which align perfectly with your requirements. My main focus in any project is to deliver exceptional quality with precision and seamless functionality - a strong reflection of the stability and optimization you require for your web app. In a timely manner, I will identify bugs, resolve calculation errors, fix broken features, improve performance and security concerns within the website while thoroughly testing each aspect. Finally, my wide range of experiences across WordPress, Magento and Shopify enable me to provide you not only with thorough audit on the current platform but also with a valuable insight into future possibilities. Whether you decide to migrate or not, I'll provide you an unbiased professional assessment to help you make an informed decision. Let's collaborate to redefine excellence in your project over long term as I'll continue to be available for necessary support!