Rajan Kalwar · Senior Software Engineer
Senior software engineer building production systems on AWS—distributed backends, event-driven architectures, containerized workloads, and GenAI applications—engineered for reliability, security, observability, and cost.
Client → API Gateway → Lambda → DynamoDB
Designed a deployable access-control system using API Gateway usage plans for tier-specific throttles and quotas. A Lambda management API handles key and plan lifecycles, while DynamoDB stores metadata without retaining raw credentials.
HTTP API → Lambda → SQS → SNS → Consumers
Engineered an event pipeline that buffers HTTP requests in SQS, processes them asynchronously with Lambda, and distributes results to independent notification and audit consumers through SNS.
Internet → ALB → Private subnets → ECS
Built comparable Fargate and EC2-backed ECS services behind an Application Load Balancer, keeping application workloads in private subnets while making the capacity-ownership trade-offs directly comparable.
we45
Cloud security training provider and hands-on learning platform.
ShopSwap Inc.
Early-stage brand collaboration platform for cross-promotion and referral tracking.
Preparie Inc.
Marketplace for home-cooked food ordering and delivery.
Bottle Tech
Nepal-based technology company building in the IoT space.
AWS
Containers are one of the most reliable ways to build and ship services, and AWS alone gives you more than a dozen ways to run them. Rather than walk the entire catalog, this note zooms in on one: AWS AppRunner — where it sits next to ECS, why it shines for small auto-scaling services, and a CloudFormation template to spin one up. First, a quick look at the popular ways to run containers on AWS:
TECH
Keeping code consistent and tested gets harder the more people touch a repo, and sooner or later some unlinted code or a failing test slips through. Husky heads that off by running linting, formatting, and tests automatically before a commit lands. This note sets up pre-commit hooks with Husky and lint-staged in a fresh NestJS project.
AWS
S3's appeal isn't only durability — it's the range of storage tiers that let you trade retrieval time for cost. This note breaks down each S3 storage class and shows how to use Lifecycle Configuration to automatically transition objects between tiers as they age, so you keep availability where it matters and trim cost where it doesn't.
I am interested in senior engineering work involving AWS architecture, distributed backends, platform reliability, and production GenAI.