Backend Developer (Mid-Level / Senior) — Fitness SaaS Platform

Job description

Locations: India, Turkey, Azerbaijan - REMOTE

We are a fast-growing startup building a gym management and fitness tracking SaaS platform. We are looking for an experienced Backend Developer to scale our existing infrastructure and ship new features.

**About the Role**

You will take ownership of our backend architecture, work closely with the frontend team on API integration, and help migrate legacy C#/.NET code to a modern Node.js stack. This is a long-term engagement with room to grow as the platform scales.

**Core Responsibilities**

- Design and build scalable backend architecture using NestJS and TypeScript
- Database design and optimization with PostgreSQL + TypeORM / Prisma
- Implement RESTful APIs, JWT authentication, CQRS, and Clean Architecture principles
- Integrate Firebase Auth and push notifications
- Set up and manage MinIO / AWS S3 file storage
- Containerization and deployment management using Docker
- Collaborate with frontend team on API integration
- Migrate legacy C#/.NET codebase to Node.js
- Write unit and integration tests; participate in code reviews

**Tech Stack**

- **Backend:** Node.js, NestJS, TypeScript, TypeORM / Prisma
- **Database:** PostgreSQL, Redis
- **DevOps:** Docker, Docker Compose, CI/CD (GitHub Actions / GitLab CI)
- **Cloud:** Firebase, MinIO / AWS S3
- **Testing:** Jest, Supertest
- **Version Control:** Git, GitHub / GitLab


**Requirements**

- 3+ years of backend development experience
- Strong proficiency in NestJS and TypeScript
- Solid understanding of RESTful API design and Clean Architecture
- Experience with PostgreSQL and ORM tools (TypeORM or Prisma)
- Familiarity with Docker and containerized deployments
- Fluent written and spoken English (for technical documentation and async communication)


**Nice to Have**

- Ability to read and understand C#/.NET code
- Experience with DDD, Microservices, GraphQL, or Event-driven architecture
- Redis caching experience
- i18n / multi-language system implementation
- Legacy codebase refactoring experience

**What We Offer**

- Long-term collaboration with a growing startup
- Work with modern technologies and best engineering practices
- Dynamic and innovative technical team
- Performance-based salary growth
- Future equity potential


**Work Type:** Remote (Anywhere)
**Engagement:** Full-time / Part-time / Freelance
**Rate:** Negotiable based on experience and portfolio


**To Apply, Please Answer:**
1. Share your experience with NestJS and TypeScript — what's the largest system you've built?
2. Have you worked on a C#/.NET to Node.js migration before? If yes, describe the approach.
3. Attach your GitHub profile or relevant portfolio links.

Applications without answers will not be reviewed.