Full-Stack Developer Needed to Fix Login Issue (FastAPI + Next.js SaaS App)

$10-30 USD

Completed

Posted 19 days ago

$10-30 USD

Paid on delivery

My SaaS platform is live on FastAPI (Python) and [login to view URL], with OpenAI API powering several features. Everything works except the most important part: users cannot log in consistently. I’ve traced the problem to the hand-off between frontend and backend—tokens leave the browser but something breaks before FastAPI accepts them. We use JWT for all auth flows, so I need someone who knows that pattern inside out and can spot subtle communication glitches fast. Your job is to dive into the codebase, reproduce the failure, isolate the root cause, and ship a clean, secure fix. Success means a new user can sign up, receive their JWT, refresh it on schedule, and hit protected endpoints without a single 401. Deliverables • Detailed diagnosis of the communication fault between [login to view URL] and FastAPI • Patch or pull request that resolves the bug and hardens the JWT flow • Brief write-up of changes so I can follow the logic and avoid regressions in future If you’ve untangled JWT headaches in a mixed FastAPI/React stack before, this should be quick work—let’s get my users logging in smoothly again.

FastAPI

Next.js

Full Stack Development

Project ID: 40232383

About the project

50 proposals

Remote project

Active 17 days ago

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Awarded to:

@thalessantana

Hello, there I can manage that in a day. Next.js+Fastapi is my expertise and login issue is not matter for me. I am ready to get started right now. Could you share your current codebase? Thank you.

$15 USD in 7 days

5.0

(1 review)

0.0

50 freelancers are bidding on average $20 USD for this job

@ninjatechsols

Respected Sir, Ninja Tech Sol is a skilled and reliable team with proven experience and strong client satisfaction. We understand that you need assistance with a login issue in your SaaS platform and are confident in our ability to deliver accurate timely results. We will provide clear communication and attention to detail to isolate the root cause and ship a clean, secure fix. Check our profile: https://www.freelancer.com/u/ninjatechsols Kind regards, Ninja Tech Sol

$20 USD in 1 day

5.0

(3 reviews)

4.0

@BenGab

Hello, I am well experienced with debugging fastapi and react applications. Add me to GitHub so I can take a look at your codebase as soon as possible. Available to start immediately.

$10 USD in 1 day

5.0

(17 reviews)

3.5

@Abdulyaqs

With over four years of web development experience, I have had ample opportunity to navigate through the complex and sometimes tricky landscape of Full Stack Development. My deep understanding of Python and proven expertise in Django and Flask have consistently equipped me to tackle and troubleshoot challenging issues that invariably arise during development. This has allowed me to build a reputation as a reliable problem solver within the field. When it comes to JWT flow and API integrations, I possess an in-depth knowledge that enables me to foresee potential issues and preemptively address them. Additionally, my ability to create clean and efficient codes has always promoted clean, secure transactions just like you need for your SaaS App. In conclusion, relatability plays an essential role in successful collaborations. As a result, working with someone who has successfully completed similar projects will give you peace of mind. By selecting me for your project, you are choosing assurance: assurance that the login issue in your app will be addressed skillfully and promptly, leaving you room to focus on building value for your users

$20 USD in 7 days

5.0

(5 reviews)

2.9

@Intelliglance786

Hi, I am an expert software engineer with skills including Full Stack Development, PHP, Git, API Development, Python, FastAPI, JavaScript and Next.js. After reviewing the project requirements, I found the project perfectly match my experience and skills. Having previously worked on similar projects, I'm confident I can complete this project perfectly. To move forward, Please contact me to discuss more regarding this project. Best Regards

$10 USD in 6 days

0.0

(0 reviews)

0.0

@sainathraoa

Hi [Client’s Name], I’m a software developer with hands-on experience in real-time projects using GenAI tools, GitHub Copilot, Angular, .NET Core, WebAPI, SQL databases, and website design. I deliver clean, scalable solutions with a focus on performance and user experience. I’d love to bring these skills to your project and ensure timely, high-quality results. Best regards, Sainath Rao.

$20 USD in 7 days

0.0

(0 reviews)

0.0

@louisbricks45

Hi there, I have good experience with handling authentication (from self auth mechanisms to third party authentications). Having said that, I can analyse your codebase and isolate the bug causing the login issue. Timeline, once I have your details, I can work right away and share a fix within 2 days. - Louis

$10 USD in 2 days

0.0

(0 reviews)

0.0

@rehanaparveens1

Hello, I am a Python developer with experience building secure web applications and debugging authentication workflows. I have hands-on experience working with FastAPI-based backends, modern frontend integrations, and implementing JWT authentication flows. I have also worked on AI-powered applications using the OpenAI ecosystem, which involved handling API communication and secure token management. I can help you reproduce the login inconsistency, trace the communication gap between the frontend and backend, and identify the root cause of the JWT failure. I focus on writing clean, secure, and scalable fixes, ensuring proper token generation, validation, refresh flow, and protected endpoint access without 401 errors. I will also provide a clear explanation of the fix and recommendations to prevent similar issues in the future. I am confident I can quickly diagnose and resolve this issue and would be happy to discuss the codebase and workflow in detail.

$10 USD in 7 days