.dev blog

Where systems
meet reality.

Practical deep dives into cloud engineering, system design, data modeling, and building reliable software that actually scales.

Start reading Explore Topics

12Articles

5Topics

22mAvg. Read

Rate LimitingRedisDistributed SystemsApi DesignScalabilityCachingPerformanceArchitectureAwsKafkaSqsSqlPostgresqlMysqlQuery OptimizationVpcCloud NetworkingSubnetsNat GatewayGcpAi ToolsProductivityManagementWorkflowClaudeSslSaasCaddyCloudfrontLets EncryptClaude CodeTeam WorkflowDeveloper ExperienceAi CodingCost OptimizationEcsFargateGravitonSpot InstancesSnsDockerContainersDevopsKubernetesDebuggingEcrRate LimitingRedisDistributed SystemsApi DesignScalabilityCachingPerformanceArchitectureAwsKafkaSqsSqlPostgresqlMysqlQuery OptimizationVpcCloud NetworkingSubnetsNat GatewayGcpAi ToolsProductivityManagementWorkflowClaudeSslSaasCaddyCloudfrontLets EncryptClaude CodeTeam WorkflowDeveloper ExperienceAi CodingCost OptimizationEcsFargateGravitonSpot InstancesSnsDockerContainersDevopsKubernetesDebuggingEcrRate LimitingRedisDistributed SystemsApi DesignScalabilityCachingPerformanceArchitectureAwsKafkaSqsSqlPostgresqlMysqlQuery OptimizationVpcCloud NetworkingSubnetsNat GatewayGcpAi ToolsProductivityManagementWorkflowClaudeSslSaasCaddyCloudfrontLets EncryptClaude CodeTeam WorkflowDeveloper ExperienceAi CodingCost OptimizationEcsFargateGravitonSpot InstancesSnsDockerContainersDevopsKubernetesDebuggingEcr

How We Reduced an AWS Bill by 40% Without Rewriting the Application

A maintenance handover turned into a full AWS cost optimization audit. By redesigning subnets, eliminating wasted public IPv4 addresses, migrating ECS workloads to Graviton, and moving Jenkins to ephemeral spot agents, we cut the monthly bill by ~40% without touching application code.

Raunak Gupta·Jun 8·26 min

Megaphone blasting envelopes beside a stack of numbered archive boxes

Scalable System Design#aws#kafka

SNS vs Kafka: When You Actually Need Pub/Sub vs an Event Log

SNS is a delivery system; Kafka is a storage system. Once that clicks, ordering, replay, backpressure, and operational cost all follow. Here's when each one breaks in production — and when to run both.

Raunak Gupta·May 27·17 min

All Articles

12 articles

A round, over-inflated cartoon whale with a strained expression carrying a stack of wooden crates on its back, one green crate tipping off — on a muted peach background

DevOps#docker#containers

Reduce Docker Image Size: Measure First, Then Cut

Your Docker image is 1 GB and you don't know why. This article shows you how to measure the actual fat with docker history and dive, then cut it systematically — multi-stage builds, base image selection, layer order, and the Alpine musl trap nobody warns you about.

Raunak Gupta·Jun 8·18 min

Chunky periwinkle crate lid straining open as peach blob squeezes out

DevOps#docker#containers

Why Your Docker Container Gets OOMKilled (Exit Code 137)

Exit code 137 means SIGKILL — almost always memory. OOMKilled: false just means the host kernel did the killing, not Docker's cgroup. The real fix is making your runtime aware of the limit it's actually running inside.

Raunak Gupta·Jun 8·19 min

Cartoon gardener pruning topiary shrub of cloud cubes

Cloud Infrastructure#aws#cost-optimization

How We Reduced an AWS Bill by 40% Without Rewriting the Application

Raunak Gupta·Jun 8·26 min

Scalable System Design#aws#kafka

SNS vs Kafka: When You Actually Need Pub/Sub vs an Event Log

Raunak Gupta·May 27·17 min

ALB cert limit blocked vs Caddy NLB factory diagram

Cloud Infrastructure#aws#ssl

SaaS Custom Domains on AWS: Past the 25 SSL Certificate Wall

Handling custom domains in a SaaS product looks simple — until your 26th customer signs up and ALB refuses to attach another SSL certificate. Here's the production architecture I built with Caddy, Let's Encrypt, and NLB to support thousands of custom domains, and the new CloudFront SaaS Manager alternative that showed up in April 2025.

Raunak Gupta·May 16·18 min

Hand-drawn cloud campus diagram with subnets and peering

Cloud Infrastructure#vpc#aws

VPCs, Subnets, and Routing — Explained Like a Real System, Not a Textbook

Most cloud networking explanations make one critical mistake — they explain cloud concepts using cloud jargon. This article fixes that with real-world analogies and production patterns.

Raunak Gupta·May 16·13 min

Figure searching paper pages with a magnifying glass

Databases#sql#performance

Why Your Database Indexes Are Not Working (And How to Fix Them)

You added an index. Your query is still slow. This article covers the debugging mindset - why indexes fail in real systems, how to diagnose the problem, and how to fix it.

Raunak Gupta·May 16·30 min

Caching machine turning tangled inputs into clean boxes

Scalable System Design#caching#redis

Caching Strategies That Work (And When They Fail)

Caching improves performance - until it starts serving stale data or becomes your biggest bottleneck. This article covers the real decisions you'll face in production.

Raunak Gupta·May 16·32 min

Overloaded request-processing machine with funnels and gauge

Scalable System Design#rate-limiting#redis

How to Design a Rate Limiter That Actually Works at Scale

Rate limiting looks simple - until you deploy it across multiple servers and it starts failing silently. This article covers what breaks in production and how to fix it.

Raunak Gupta·May 16·28 min

Where systems meet reality.

How We Reduced an AWS Bill by 40% Without Rewriting the Application

SNS vs Kafka: When You Actually Need Pub/Sub vs an Event Log

All Articles

Reduce Docker Image Size: Measure First, Then Cut

Why Your Docker Container Gets OOMKilled (Exit Code 137)

How We Reduced an AWS Bill by 40% Without Rewriting the Application

SNS vs Kafka: When You Actually Need Pub/Sub vs an Event Log

SaaS Custom Domains on AWS: Past the 25 SSL Certificate Wall

VPCs, Subnets, and Routing — Explained Like a Real System, Not a Textbook

Why Your Database Indexes Are Not Working (And How to Fix Them)

Caching Strategies That Work (And When They Fail)

How to Design a Rate Limiter That Actually Works at Scale

All Articles

Reduce Docker Image Size: Measure First, Then Cut

Why Your Docker Container Gets OOMKilled (Exit Code 137)

How We Reduced an AWS Bill by 40% Without Rewriting the Application

SNS vs Kafka: When You Actually Need Pub/Sub vs an Event Log

SaaS Custom Domains on AWS: Past the 25 SSL Certificate Wall

VPCs, Subnets, and Routing — Explained Like a Real System, Not a Textbook

Why Your Database Indexes Are Not Working (And How to Fix Them)

Caching Strategies That Work (And When They Fail)

How to Design a Rate Limiter That Actually Works at Scale

Where systems
meet reality.