Rajeev Gade
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Backend Engineering

Serverless Healthcare Integration Platform

Swing Therapeutics · Lead Software Engineer / Primary Contributor

Swing Therapeutics | Backend Engineering / Cloud Architecture

Built and evolved a NestJS serverless backend that connected healthcare and operational systems, exposed secure REST APIs, ran scheduled jobs, and executed configurable asynchronous workflows on AWS.

NestJSTypeScriptAWS LambdaAPI GatewaySQSMySQLFirebase
Abstract architecture diagram — no product screenshots

Overview

A NestJS serverless integration platform with scheduled jobs and asynchronous workflow execution. The service exposed secure REST APIs on AWS Lambda behind API Gateway, coordinated identity, messaging, scheduling, payments, support, and clinical systems, and moved longer-running automation to SQS workers. GraphQL was used only as a typed outbound client to an external clinical platform — the application’s public API remained REST.

My Contribution

  • Designed and extended a configurable workflow engine with Firestore-backed definitions, SQS workers, retries, cancellation, and execution tracking
  • Delivered guarded internal REST APIs over MySQL with filtering, pagination, caching, and reporting capabilities
  • Integrated identity, messaging, scheduling, payments, support, and analytics platforms through modular NestJS services
  • Expanded typed GraphQL client operations against an external clinical platform while keeping the application API REST-based
  • Supported multi-stage Serverless Framework deployments with SSM and Secrets-managed configuration and GitHub Actions
  • Implemented scheduled Lambda jobs for synchronization, reminders, processing, and operational health checks

Technical Architecture

  1. API Gateway → NestJS on AWS Lambda (REST APIs)
  2. MySQL and Firestore persistence
  3. S3 for files and exports; ElastiCache Valkey for selected cached reads
  4. SQS worker Lambda for asynchronous workflows
  5. Scheduled Lambda jobs for sync and operational processing
  6. Outbound GraphQL client to an external clinical system
  7. SSM / Secrets Manager config via Serverless Framework and GitHub Actions

Engineering Challenges

  • Separating synchronous REST work from asynchronous SQS workflows with retries, cancellation, and DLQ behavior
  • Mixed Firestore and MySQL persistence with clear ownership boundaries
  • Typed outbound GraphQL integration without changing the public REST contract
  • Multi-stage deployment configuration, caching, and operational access controls
  • Keeping scheduled jobs and workflow execution observable without blocking API requests

Reliability, Privacy, and Security Considerations

Integration backends need careful secret management, controlled access, and clear separation between request/response APIs and longer-running jobs. This portfolio omits partner names, queue or bucket identifiers, VPC details, patient payloads, and unsupported scale or latency claims.

Engineering Outcomes

  • Centralized backend integration logic for healthcare and operational systems
  • Moved long-running automation out of synchronous API requests
  • Improved operational visibility through tracked workflow executions and logs
  • Supported repeatable multi-stage deployments

Technologies

  • NestJS, TypeScript, REST, Serverless Framework, Jest, GitHub Actions
  • AWS Lambda, API Gateway, SQS, SNS, S3, ElastiCache Valkey, SES, CloudWatch, VPC
  • MySQL, Prisma, TypeORM, Firebase/Firestore, Auth0, Flagsmith
  • SSM Parameter Store, Secrets Manager, outbound GraphQL client