Backend for VPN application

Budget: 25000 UAH Deadline: 14 days

Good day.

I have carefully read your technical specifications. The architecture is clear: Marzban as the core VPN, and a separate integration backend on FastAPI for business logic, Apple IAP, and access management. This approach is absolutely correct, as Marzban indeed covers most of the VPN logic.

I have already worked with Python / FastAPI, Docker infrastructure, PostgreSQL, and Redis, so implementing such a backend is clear to me.

What I can implement within this project:

• Integration backend on FastAPI (async)
• Device registration + JWT authorization
• Validation of Apple In-App Purchases (receipt validation)
• Support for App Store Server Notifications V2
• Integration with Marzban REST API
• Automatic creation / blocking of users in Marzban
• Endpoint for issuing VPN configs for iOS
• Load balancing logic between nodes
• Redis for rate limiting
• PostgreSQL schema (users / subscriptions / marzban_users / locations)
• Telegram alerting for node failures or errors
• Full docker-compose deployment
• Nginx + HTTPS (Let's Encrypt)
• Swagger API documentation
• README with instructions for launching and scaling

I can also immediately lay down a proper project structure so that the backend can easily scale as the number of users grows.

To more accurately assess the work, I would like to clarify a few points:

Is the VPS already prepared, or does the infrastructure need to be deployed from scratch?

Is Marzban already up and running, or does it also need to be deployed?

Is there a test iOS application for checking IAP?

Are multiple VPN nodes planned right away, or just one for now?

After these clarifications, I will be able to provide an exact cost and timeline.

Overall, the project looks well thought out, and I believe we can quickly bring it to a working state.

I am ready to discuss the details. Expand

Budget: 27000 UAH Deadline: 30 days

Hello. I work with FastAPI/Node.js. I am ready to collaborate. Please contact me.

Budget: 5999 UAH Deadline: 3 days

Hello.

I am a NodeJS developer. I am ready to take on the task. Write to me, we will discuss.

Budget: 12345 UAH Deadline: 123 days

Hello! I have experience in developing backend solutions on FastAPI and integrating with VPN infrastructures.

I am ready to implement an integration service for your application:

Integration with Marzban API: automation of user creation/blocking and node management.

Apple IAP: complete logic for receipt validation and handling App Store Server Notifications (V2).

Architecture: PostgreSQL for data, Redis for limits, full containerization via Docker Compose.

Additionally: I will set up Telegram alerting about server status and load balancing between locations.

I guarantee clean asynchronous code and detailed API documentation in Swagger.
I would be happy to discuss the details and start working. Expand

Budget: 24000 UAH Deadline: 8 days

I have previously implemented similar functionality for WireGuard using FastAPI and PostgressDB. Of course, your technical specifications are different, but there is nothing difficult here, so I am ready to take it on.

Budget: 6000 UAH Deadline: 1 day

Good day! I am ready to complete this project. Extensive experience in developing various applications.

Budget: 6000 UAH Deadline: 1 day

Good day!
I am developing in Python!
I have experience with everything in the technology stack.
Write to me - we will communicate.

Budget: 6000 UAH Deadline: 10 days

Hello, I have already developed a website for VPN, so I have experience in this. I would like to clarify a couple of details in private messages.

Budget: 5800 UAH Deadline: 2 days

Good day! My name is Svitlana. I have the relevant experience and free time to carry out your project effectively. I work for results, I am responsible and punctual. I am ready to start working today. I look forward to your response!

Budget: 16000 UAH Deadline: 10 days

Good day, I have reviewed the technical specifications, the task is clear. I am ready to implement the backend for the VPN application. I will complete everything with quality and within the agreed deadlines.

Budget: 10000 UAH Deadline: 1 day

Hello, I implement without problems, I have a lot of experience in implementation.
Hello, I implement without problems, I have a lot of experience in implementation.

Budget: 15000 UAH Deadline: 14 days

Hello! I reviewed your project brief - it's an interesting project. I can create a backend on FastAPI for integration, ensuring a stable connection between the iOS app and Marzban.

What you will get:

Payments will be fine - I will set up Apple IAP and their V2 notifications to quickly respond to refunds or cancellations.

I will create a load balancer that will track which node is less loaded through Redis and direct traffic there for stable speed.

I will also think about security - JWT tokens and limits on the number of requests, as you want. Monitoring: I will set up a Telegram bot for notifications about the status of nodes and critical errors.

I will package everything in Docker and create proper documentation in Swagger. When do we start? Expand

Budget: 15000 UAH Deadline: 20 days

Hello, I have 4 years of web development experience, I have mostly worked with FastAPI, we can discuss the details further in private messages, I will be happy to help.

Budget: 6000 UAH Deadline: 3 days

Good evening!

I have experience in backend development for VPN services, particularly using Marzban. I am ready to take on your project, refining the necessary logic and ensuring stable operation.

Feel free to contact me in private messages to discuss the details and your proposal regarding the cost.

Budget: 12000 UAH Deadline: 10 days

Good day

My name is Dmytro, from the company King Kong Lab.

I have reviewed your technical specifications for the backend of the iOS VPN application. We have experience in developing backend systems in Python (FastAPI), working with Docker infrastructure, API integrations, and building scalable services. We also have experience with subscriptions, authorization via JWT, Redis, PostgreSQL, and high-load systems.

We can implement the Integration Backend that will work with Marzban via API and provide the business logic of the application: device registration, validation of Apple In-App Purchases subscriptions, creation and management of users in Marzban, issuing VPN configurations, blocking access after subscription expiration, and server selection with load balancing.

We can also implement an API security system (JWT, rate limiting via Redis), logging, support for App Store Server Notifications, node monitoring, and sending critical messages to Telegram. The infrastructure will be deployed via Docker (FastAPI, Marzban, PostgreSQL, Redis, Nginx) with HTTPS and the possibility of further scaling.

We will provide a complete Git repository, docker-compose, API documentation via Swagger, deployment and scaling instructions. After launch, we will provide warranty support and assist with the initial stages of scaling.

We are ready to discuss the project details, estimate the stages of work, and propose an optimal cost for implementation. Expand

Budget: 6000 UAH Deadline: 1 day

Good day!

I have reviewed the description and understand that the main logic has already been implemented through Marzban, so the main task is to correctly integrate the backend, set up the interaction of services, and implement the necessary functionality according to the technical specifications.

I have experience in backend development, API integrations, and server infrastructure, so I will be able to assist with the implementation, configuration, and stable operation of the system.

I suggest we move to private messages — I will review the file with the technical specifications and will be able to provide an accurate estimate of the cost and deadlines for completion.