Website r3 Consultant
Job Title: Backend Developer (FAST API + AWS)
Location: Pune (Hybrid)
Work Experience: 4-8 years
Job Summary :
We are looking for a highly skilled Backend Engineer with strong experience in FastAPI, AWS infrastructure, authentication systems, payment integrations, monitoring systems, sockets, and scalable backend architecture. The candidate should be comfortable building production-grade APIs, working with real-time systems, and handling cloud-native deployments.
This role involves working on scalable AI-driven web and mobile platforms with integrations across payments, subscriptions, authentication, analytics, monitoring, and real-time communication systems.
Required Skills
Backend Development
Strong experience with Python and FastAPI
Experience designing scalable REST APIs and async backend systems
Deep understanding of backend architecture, middleware, dependency injection, and background task handling
Strong experience with WebSockets, socket lifecycle management, reconnection handling, and real-time communication systems
Experience handling concurrent socket connections and event-driven systems
Knowledge of microservice-oriented architecture is a plus
AWS & Cloud Infrastructure
Strong hands-on experience with:
EC2
S3
DynamoDB
Load Balancers
Experience with production deployments, scaling, monitoring, and security hardening
Understanding of CI/CD pipelines and deployment automation
Database Experience
Strong experience with DynamoDB
Must understand:
GSIs (Global Secondary Indexes)
Query optimization
Partition key design
Scaling considerations
Single-table design concepts
Experience with MongoDB/PostgreSQL is a plus
Authentication & Security
Experience with Auth0 or similar authentication providers
Understanding of:
JWT authentication
Session handling
OAuth flows
RBAC / permission systems
Secure API design
Experience implementing secure backend authorization flows
Payments & Subscription Systems
Experience integrating Stripe APIs
Knowledge of:
Subscription lifecycle management
Webhooks
Payment intents
Billing flows
Invoice handling
Experience with RevenueCat integration for mobile subscription management is highly preferred
Monitoring & Reliability
Experience with monitoring and observability tools such as:
CloudWatch
Datadog
Grafana
Prometheus
Sentry
Ability to monitor logs, infrastructure health, API performance, socket reliability, and production incidents
Experience with alerting systems and production debugging workflows
Additional Preferred Skills
Experience supporting Flutter or React-based applications
Familiarity with mobile backend requirements
Experience debugging production systems and improving reliability/performance
Responsibilities
Develop and maintain scalable backend APIs using FastAPI
Design secure and efficient backend architecture
Manage AWS infrastructure and deployment pipelines
Build real-time communication systems using WebSockets/sockets
Build payment and subscription systems using Stripe and RevenueCat
Optimize DynamoDB schemas and GSI usage for performance
Implement authentication and authorization systems
Monitor infrastructure, backend services, socket systems, and production environments
Improve system reliability, performance, and scalability
Collaborate with frontend, mobile, and DevOps teams
Participate in debugging, testing, and production monitoring
Ideal Candidate should have:
Strong problem-solving ability
Comfortable working in fast-paced startup environments
Able to independently design and implement backend systems
Good understanding of scalability and production engineering
Strong ownership mindset and debugging skills
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