Senior Node.js Developer / Telegram Bot Developer

We are a startup developing cloud-routers.com, a platform that allows users to deploy and manage their own proxy servers. We recently completed the development of a Telegram bot designed to test the Cloud-Routers API from the perspective of B2B customers. Although everything worked correctly in the development environment, after deploying to production we encountered a blocking issue with Stripe payments. Unfortunately, the developer who built the project is unavailable for the next 2–3 months due to personal circumstances. We are urgently looking for an experienced developer who can help us debug and maintain our MVP on a fixed-price basis. Responsibilities Your first task will be to fix a production issue related to payments. The payment flow worked correctly in the development environment, so you will need to compare the development and production configurations, identify what changed, and fix the production deployment. Current Blocking Issue Users can configure a proxy server in the Telegram bot and then proceed to the payment section. At the moment, Stripe is our only payment provider. In the development environment, clicking the Stripe button redirected users to the correct Stripe Checkout page. In production, however, the button redirects users to an incorrect URL instead of the Stripe payment page. Your task is to identify the cause and fix the issue. What Happens Next? We are currently onboarding our first B2B customers. As the integration process continues, there will almost certainly be additional bugs and edge cases. We are looking for a developer who can respond to bug reports and deliver fixes within 24 hours whenever possible. How We Work We work on a fixed-price basis rather than hourly. Our process is: 1. We send you a bug report together with our preliminary time estimate and pricing based on $40/hour 2. You review the estimate and agree on the final fixed price for the task. 3. We fund an Upwork Escrow contract. 4. You complete the work. 5. Once the task is finished and verified, we release the escrow payment. Tech Stack Frontend * TypeScript * React * Redux Toolkit (RTK) Backend * TypeScript * Node.js * NestJS Telegram Bot * TypeScript * Node.js * NestJS * Telegram Bot API * GrammY Payment Gateway * Stripe Requirements 1. Proven experience building commercial Telegram bots (you should be able to demonstrate bots you have personally developed). 2. Excellent knowledge of JavaScript and TypeScript. 3. Strong commercial experience with Node.js and NestJS. 4. Strong experience with React and Redux Toolkit (RTK). Interview Process Before we start working together, there will be a technical interview with a live coding session. During the interview, the use of AI assistants and IDE code-completion tools is not allowed. We have no problem with developers using these tools in their daily work, but for the interview we want to evaluate your actual technical skills. This version reads naturally for international developers and is suitable for posting on Upwork or similar freelance platforms.