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I will fix nodejs or python backend bugs and API errors
Nicolas S
About this gig
Is your Node.js or Python backend throwing errors or returning unexpected API responses? I will investigate and fix a clearly scoped issue in your existing application.
My experience includes Node.js, Python, AWS and penetration testing, bringing a security-aware approach to debugging.
I can help with backend exceptions, API request and response errors, authentication flows, input validation and third-party integrations. Framework and environment compatibility are confirmed before ordering.
Every package includes investigation, the agreed code fix, verification and a clear explanation. Standard adds a regression test; Premium covers one more complex agreed flow with regression tests and a documented handoff.
Please contact me before ordering with reproduction steps and sanitized logs so we can confirm scope, feasibility and delivery time. Packages are not unlimited bug fixes. New features, full rewrites, pentests, infrastructure migrations and production deployment are excluded unless separately agreed.
Work is performed only on systems you own or are authorized to modify, preferably in a test environment. Never send passwords, API keys or customer data in your brief.
Get to know Nicolas S
Nicolas S
- FromBrazil
- Member sinceMay 2025
- Avg. response time1 hour
Languages
English, Portuguese
I'm a Web Developer and Cybersecurity Specialist focused on secure web applications, API security, and penetration testing.
I work with Python, Node.js, React, Linux, and AWS, combining software development with hands-on security testing.
My services include vulnerability assessments, API security reviews, secure coding, bug fixes, and web development.
I'm AWS Certified Cloud Practitioner, with practical experience using Burp Suite, OWASP ZAP, and Nmap.
I focus on delivering reliable solutions, clear communication, and actionable security recommendations.
My Portfolio
FAQ
Should I contact you before ordering?
Yes. Send the expected behavior, reproduction steps and sanitized error logs. I will review scope, compatibility and feasibility before we choose a package. Complex or unrelated issues may need a custom offer.
What will I receive?
The agreed code fix, a summary of the cause and changes, and verification steps or results. Standard includes a regression test. Premium includes regression tests for the agreed flow and handoff notes.
What does a revision include?
A revision addresses the delivered fix against the original agreed requirements. New features, unrelated bugs, extra integrations and changes to the original scope are not included.
Do you support AWS and production deployments?
I have AWS experience and can investigate application issues in an agreed AWS environment. Production deployment, infrastructure changes and migrations are not included by default. Any access must be temporary, least-privilege and explicitly authorized.
What access do you need?
A minimal reproducible example or relevant code, runtime versions, setup steps and sanitized logs. A test environment is preferred. Never paste passwords, API keys, production secrets or personal customer data into the brief.
