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I will develop, fix bugs supabase firebase node js backend API authentication database
Esther B
About this gig
Is your backend throwing errors, crashing, or refusing to connect with your database or third-party APIs? I can quickly identify the root cause and deliver reliable, secure, and scalable fixes.
I specialize in backend bug fixing, API integration, authentication, database troubleshooting, and performance optimization using Node.js, Express.js, JavaScript, Supabase, Firebase, PostgreSQL, MongoDB, SQL, and AWS. Whether you're building a SaaS platform, AI application, eCommerce website, or custom web application, I'll ensure your backend runs smoothly.
Services include:
- Backend bug fixing
- REST API development & debugging
- Third-party API integration
- JWT & OAuth authentication
- Stripe & PayPal integration
- Webhook setup and fixes
- Database design & optimization
- PostgreSQL, MongoDB, Firebase & Supabase fixes
- CORS, server and deployment issues
- Performance optimization
- Security improvements
- Cloud deployment support
Why choose me?
- Clean and maintainable code
- Fast troubleshooting and delivery
- Secure backend solutions
- Scalable architecture
- Clear communication
Before placing an order, please contact me with your requirements so I can review your project and recommend the best solution.
Get to know Esther B
Esther B
Backend Developer, API Integration, Node js, Supabase, Firebase, AWS, PostgreSQL
- FromGermany
- Member sinceJul 2026
- Avg. response time8 hours
Languages
German, English, Spanish, French, Italian
Backend developer specializing in scalable APIs, database architecture, and secure web applications. I build REST APIs, backend systems, authentication, payment gateways, AI integrations, and automation workflows using Node.js, Express.js, Supabase, Firebase, PostgreSQL, MongoDB, AWS, and SQL. I integrate Stripe, webhooks, third-party APIs, CRMs, and cloud services while optimizing performance, security, and scalability for SaaS, AI, eCommerce, and custom web applications. I also develop serverless functions, API debugging, cloud deployment, database optimization, and custom backend solutions.
Other Software Development Services I Offer
FAQ
Can you fix my existing backend without rebuilding it?
Yes. I first identify the root cause, then fix only the affected components while preserving your existing architecture whenever possible. Whether it's a Node.js, Express.js, API, database, or authentication issue, my goal is to provide a stable solution with minimal disruption.
What backend technologies do you support?
I work with Node.js, Express.js, JavaScript, Supabase, Firebase, PostgreSQL, MongoDB, SQL, REST APIs, JWT, OAuth, Stripe, PayPal, webhooks, AWS, and cloud deployments. If your project uses related backend technologies, feel free to contact me before ordering.
Can you fix API integration and webhook issues?
Absolutely. I troubleshoot broken API endpoints, authentication failures, webhook errors, timeout issues, response validation, third-party integrations, and data synchronization problems to ensure reliable communication between your services.
Can you solve database connection and query errors?
Yes. I fix database connection failures, optimize slow queries, resolve migration issues, improve indexing, repair schema problems, and troubleshoot PostgreSQL, MongoDB, Firebase, and Supabase databases for better stability and performance.
Can you help with login and authentication problems?
Yes. I resolve JWT authentication issues, OAuth integrations, session management, role-based access control, password reset flows, token refresh problems, and authorization errors while following backend security best practices.
My backend crashes with 500 errors. Can you fix it?
Yes. I analyze server logs, trace exceptions, identify faulty code, resolve configuration issues, fix broken endpoints, and eliminate backend bugs causing 500 errors, crashes, or unstable application behavior.
Do you optimize backend performance?
Yes. I improve API response times, optimize database queries, reduce server load, implement caching strategies, remove bottlenecks, and enhance scalability so your backend performs efficiently under increasing traffic.
Can you deploy or fix deployment issues?
Yes. I can troubleshoot deployment problems on AWS, Vercel, Render, Railway, VPS, and other cloud platforms. I also resolve environment variable, server configuration, SSL, and production deployment issues.
What do you need before starting my project?
Please provide your project details, source code or repository access, error messages, screenshots if available, hosting information, and a clear description of the issue. The more details you provide, the faster I can diagnose and fix it.
Why should I contact you before placing an order?
Every backend issue is different. Contacting me first allows me to review your requirements, estimate the scope accurately, recommend the right package, and ensure you receive the most effective solution without unnecessary costs or delays.
