Principal Backend Developer

We are building an advanced SaaS platform designed to handle high-volume, real-time interactions across multiple business domains. The system enables seamless customer engagement through web, mobile, and QR-based touchpoints without requiring user registration. It supports hybrid operations for both real-time queuing and appointment scheduling at scale.

This role is for a true backend architect, someone who thrives on building highly optimized APIs, tackling complex algorithms, and designing systems that balance performance, security, and scalability.

Position Overview

We are looking for a very senior-level Backend Engineer to design and implement scalable, performant, and secure backend architecture. You'll work on a complex system that must support real-time communication, geolocation queries, advanced analytics, and seamless integration with third-party services.

You will have full autonomy over backend architecture decisions, performance tuning, and technology choices to ensure the platform can scale globally.

Key ResponsibilitiesAPI & Communication Layer

• Architect, develop, and maintain Fastify 5.x REST APIs with advanced routing and middleware design
• Implement real-time WebSocket communication with failover and scalability considerations
• Design and secure authentication & authorization systems (JWT, OAuth, Apple Sign-In)
• Apply advanced rate limiting, request validation, and security middleware
• Deliver OpenAPI/Swagger documentation with automated updates

Core Platform Backend

• Service Discovery Engine: Geolocation-based algorithms for nearby service search at scale
• Smart Recommendation System: ML-driven suggestions using behavioral analytics
• Real-time Comparison API: Live wait-time comparison between multiple businesses
• Review & Rating System: Moderation logic, spam/fraud detection algorithms
• Advanced Search: Full-text and fuzzy search using MongoDB Atlas Search or Elasticsearch

Business Logic Layer

• Queue Management System: Real-time queuing with dynamic prioritization rules
• Appointment Scheduler: Conflict resolution, availability computation, exception handling
• QR Code Services: Customizable QR generation with parameterized metadata
• Working Hours Engine: Complex scheduling including exceptions, holidays, and special days
• Analytics Engine: Real-time metric ingestion, aggregation, and visualization hooks

Infrastructure & DevOps

• Optimize MongoDB schemas, indexes, and aggregation pipelines for high-performance queries
• Implement caching strategies with Redis for low-latency responses
• Manage background job processing with Bull Queue
• Monitor and debug production systems using Prometheus, Grafana, Winston, and PM2
• Build containerized services with Docker, with an eye toward Kubernetes orchestration

Requirements Must Have

• 7+ years backend development experience with (production-grade systems)
• 5+ years with TypeScript in large-scale applications
• Proven expertise in REST API architecture and distributed system design
• Deep understanding of MongoDB and geospatial queries
• Experience implementing authentication & security at scale (JWT, OAuth, password hashing, secure headers)
• Real-time systems expertise with WebSockets and high-concurrency event handling
• CI/CD pipeline design and Git-based workflows

Nice to Have

• Fastify framework expertise in high-load environments
• Knowledge of geospatial algorithms, GIS, and spatial indexing
• Microservices architecture experience
• Search technology experience (MongoDB Atlas Search, Elasticsearch)
• Redis optimization for caching/session management
• Docker/Kubernetes orchestration at scale
• Basic ML/AI understanding for building recommendation engines

Soft Skills

• System architecture mindset; able to think several steps ahead for scaling and maintainability
• Strong communication skills, capable of leading technical discussions with engineering and product teams
• Security-first development approach
• Commitment to continuous learning and technology evolution
• Ability to mentor mid-level and junior developers in best practices

What We Offer

• Work on a high-traffic, real-time system serving thousands of concurrent users
• Technical challenges across geolocation, spatial search, ML recommendations, and microservices
• Flexible working hours, with remote/hybrid options
• Complete autonomy in technical decision-making
• Opportunity to shape the platform's core architecture and engineering standards

If you are a backend leader who thrives in complex, high-scale environments and loves designing bulletproof architectures, this role will put your skills to the ultimate test.