AI & ML
Why Open Web RAG Fails in AWS Bedrock
Building production-ready GenAI applications requires grounding your Large Language Models (LLMs) in real-time information. While static…
MNMaleesha Nuwanthi Kolombage · · 3 min read
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Every article published on AWS Fullstack, newest first: architecture, serverless, data, security and the platform work in between.
Data
DynamoDB Data Modeling: How to Design Tables for Scalability and Performance
DynamoDB Data Modeling: How to Design Tables for Scalability and Performance Learn how to model data in Amazon DynamoDB using access patterns, partition keys, sort keys, and GSIs with practical …
Tharaka Chathuranga · · 7 min read
AI & ML
5 Mistakes That Wasted Our Money on AWS SageMaker
5 Mistakes That Wasted Our Money on AWS SageMaker (and the Free Checks That Stop Them) We paid for GPU time just to find out our training jobs were broken. Here’s what went wrong. Imagine booking a …
Nishara Ramasingha · · 4 min read
Frontend
Fixing NoCredentials and “Auth UserPool Not Configured” Errors in Amplify Gen 2
Fixing NoCredentials and “Auth UserPool Not Configured” Errors in Amplify Gen 2 Setting up a new Gen 2 app usually goes smoothly. You run the sandbox, the backend deploys, the frontend picks it …
Poorna Theekshana · · 5 min read
Serverless
Why Your AWS Lambda Shouldn’t Fire and Forget
Why Your AWS Lambda Shouldn’t Fire and Forget That background promise might never finish, even when your code looks perfectly fine. Imagine you’re building an API with AWS Lambda. After saving …
Bhathiya Ranasinghe · · 8 min read
AI & ML
When Not to Use Similarity Search in a RAG Pipeline
When Not to Use Similarity Search in a RAG Pipeline When we learn about RAG, the usual flow feels very natural. A user asks a question, we create an embedding, search the vector database, retrieve …
Navindu Chathuranga · · 5 min read
Serverless
AWS Lambda in 2026: Web Functions, MicroVMs, and Durable Functions Explained
AWS Lambda in 2026: Web Functions, MicroVMs, and Durable Functions Explained AWS Lambda is no longer one service. Here’s what each new Lambda option does, and which one you should actually use. AWS …
Nishara Ramasingha · · 7 min read
Data
Why DynamoDB Throttles Even When Capacity Is Available
Why DynamoDB Throttles Even When Capacity Is Available Understand how DynamoDB partition keys, physical partitions, capacity limits, and write sharding affect application performance. Your …
Tharaka Chathuranga · · 7 min read
Data
How DynamoDB Really Works
How DynamoDB Really Works Partitions, replication, and consistency behind every read and write. Imagine your application sends a PutItem request to DynamoDB. A few milliseconds later, you get a …
Tharaka Chathuranga · · 8 min read
Security
How Amazon CloudFront Works
How Amazon CloudFront Works Understand CDNs, edge locations, origins, caching, cache behaviors, and security through the CloudFront request lifecycle. Imagine you have deployed a website in an AWS …
Dhanushka Godage · · 6 min read
Serverless
Reduced Lambda Bundle Size in Amplify Gen 2
Reduced Lambda Bundle Size in Amplify Gen 2 A Lambda that just reads from DynamoDB, talks to a couple of AWS services, and returns a JSON payload should be tiny. So when I noticed some of our …
Tharaka Chathuranga · · 7 min read
DevOps
Setting Up Pull Request Preview Environments in Amplify Gen 2
Setting Up Pull Request Preview Environments in Amplify Gen 2 A pull request changes an API route and the two screens that call it. The diff looks right. Two people approve it because reading a diff …
Poorna Theekshana · · 5 min read
Frontend
Custom Domain Stuck on Pending Verification: How to Fix It
Custom Domain Stuck on Pending Verification: How to Fix It Maya had one task left before launch week: point example.com at the Amplify app. She opened the console, added the domain, and Amplify …
Poorna Theekshana · · 5 min read
Frontend
Fixing 404s on Page Refresh for React and Vue SPAs with Amplify Rewrite Rules
Fixing 404s on Page Refresh for React and Vue SPAs with Amplify Rewrite Rules Ryan had shipped the internal reporting dashboard on a Friday. React with React Router, built by Vite, hosted on Amplify …
Poorna Theekshana · · 5 min read
Frontend
Build Passes, but the Site Returns 500: Debugging Next.js SSR on Amplify Hosting
Build Passes, but the Site Returns 500: Debugging Next.js SSR on Amplify Hosting The build went green. Every step passed, the deployment finished, and the branch URL opened to a blank page with 500 | …
Poorna Theekshana · · 6 min read
AI & ML
What If You Could Control Every AI Call From One Place?
What If You Could Control Every AI Call From One Place? A practical guide to putting one layer between your application and AI models, so you can track costs, switch models, manage access, and …
Navindu Chathuranga · · 14 min read
Serverless
Fixing Environment Variables That Are Undefined at Runtime in Next.js SSR on Amplify
Fixing Environment Variables That Are Undefined at Runtime in Next.js SSR on Amplify The app worked on my machine. API_BASE_URL lived in .env.local, the route handler called the API, and the page …
Poorna Theekshana · · 5 min read
Serverless
Understanding the APPSYNC_JS Runtime
Understanding the APPSYNC_JS Runtime Learn what JavaScript works inside APPSYNC_JS, where it differs from Node.js, and how to avoid common resolver errors in AWS AppSync and Amplify Gen 2. If you …
Tharaka Chathuranga · · 4 min read
Data
Multi-Tenant RAG on Amazon S3 Vectors - Part 3: The Pipeline
Multi-Tenant RAG on Amazon S3 Vectors - Part 3: The Pipeline How to Implement a Multi Tenant RAG with AWS S3 Vectors Part 3 of 3. Part 1 set six requirements and argued that only a per-tenant …
Chameera Dulanga · · 10 min read
Data
Multi-Tenant RAG on Amazon S3 Vectors - Part 2: The Cost Model
Multi-Tenant RAG on Amazon S3 Vectors - Part 2: The Cost Model Part 2 of 3. Part 1 set six requirements and showed that only a per-tenant resource with its own ARN satisfies them. This part is the …
Chameera Dulanga · · 8 min read
AI & ML
Multi-Tenant RAG on Amazon S3 Vectors - Part 1: The Isolation Model
Multi-Tenant RAG on Amazon S3 Vectors - Part 1: The Isolation Model Part 1 of 3. This part is the requirements and the isolation model. Part 2 is the cost model with the arithmetic. Part 3 is the …
Chameera Dulanga · · 7 min read
Serverless
Access Multiple DynamoDB Tables with an AppSync JS Unit Resolver
Access Multiple DynamoDB Tables with an AppSync JS Unit Resolver Use BatchGetItem and TransactWriteItems in Amplify Gen 2 JavaScript Unit Resolver to access multiple DynamoDB tables without adding a …
Tharaka Chathuranga · · 7 min read
AI & ML
Beyond Similarity Search: Metadata Filtering for RAG with Amazon S3 Vectors
Beyond Similarity Search: Metadata Filtering for RAG with Amazon S3 Vectors Semantic search is one of the most useful parts of RAG. A user does not need to ask a question using the exact same words …
Navindu Chathuranga · · 6 min read
Serverless
Scaling Amplify Gen 2: Splitting Lambda Functions Across Stacks
Scaling Amplify Gen 2: Splitting Lambda Functions Across Stacks Use a centralized defineFunction wrapper to automatically distribute Lambda functions across resource groups as your backend grows. On …
Tharaka Chathuranga · · 7 min read
AI & ML
Building a Structure-Aware RAG Chunking Pipeline with Amazon Bedrock and S3 Vectors
Building a Structure-Aware RAG Chunking Pipeline with Amazon Bedrock and S3 Vectors A RAG system can use a good embedding model and a reliable vector database, but the results can still feel less …
Navindu Chathuranga · · 10 min read
Serverless
How to Get Started with JavaScript Resolvers in AWS Amplify Gen 2
How to Get Started with JavaScript Resolvers in AWS Amplify Gen 2 Learn how AppSync JavaScript resolvers work in Amplify Gen 2, when to use them, their runtime limitations, and how to build your …
Tharaka Chathuranga · · 12 min read
Data
Why DynamoDB Uses Eventual Consistency
Why DynamoDB Uses Eventual Consistency Understanding Replication, Partitions, and Leader Nodes in Eventual Consistency If you’ve ever worked with Amazon DynamoDB, you’ve probably come across …
Maleesha Nuwanthi Kolombage · · 6 min read
AI & ML
Building a Serverless RAG Pipeline with Amazon S3 Vectors and Amazon Bedrock
Building a Serverless RAG Pipeline with Amazon S3 Vectors and Amazon Bedrock When I first learned about Retrieval-Augmented Generation (RAG), the architecture looked simple: Store some documents → …
Navindu · · 8 min read
Security
Why IAM Policy Size Breaks an AWS Deployment?
Why IAM Policy Size Breaks an AWS Deployment? Your Lambda’s permissions didn’t get more dangerous. They got too long to write down. Everything was working. The application was growing, new …
Maleesha Nuwanthi Kolombage · · 5 min read
Security
Authentication vs Authorization in AWS Amplify
Authentication vs Authorization in AWS Amplify Why Permissions Feel Confusing in Amplify When you first start using AWS Amplify, authentication often feels simple. You add Auth, sign-up works …
Rashindu Sithara · · 6 min read
Architecture
PDFs Generate with Puppeteer and Amazon S3
PDFs Generate with Puppeteer and Amazon S3 Learn how to use Puppeteer with Amazon S3 Bucket to generate PDFs, screenshots, and store files securely in AWS. Many teams need a simple way to generate …
Pathum Jayaweera · · 6 min read
Data
AWS DynamoDB Eventual Consistency VS Strong Consistency
AWS DynamoDB Eventual Consistency VS Strong Consistency Amazon DynamoDB reads data from tables, local secondary indexes (LSIs), global secondary indexes (GSIs), and streams. Both tables and LSIs …
Maleesha Nuwanthi Kolombage · · 3 min read
Architecture
What Is Amazon EC2? A Beginner’s Guide to Virtual Servers in AWS
What Is Amazon EC2? A Beginner’s Guide to Virtual Servers in AWS Amazon EC2 (Elastic Compute Cloud) is a service that provides virtual servers, called instances, in the cloud. You can choose the …
Avishka Weeraddana · · 4 min read
AI & ML
Amazon Bedrock AgentCore Explained for Developers
Amazon Bedrock AgentCore Explained for Developers What is Amazon Bedrock AgentCore? Most AI agent demos look strong for five minutes. Then the hard questions show up. Where does the agent run? How …
Binara Prabhanga · · 6 min read
Data
Amazon S3 Account Regional Namespaces
Amazon S3 Account Regional Namespaces Simplifying S3 Bucket Naming Across AWS Regions Cloud storage is at the heart of modern applications, and Amazon S3 (Simple Storage Service) has long been one of …
Maleesha Nuwanthi Kolombage · · 2 min read
Containers
Automating Docker Image Deployment to AWS ECR with GitHub Actions
Automating Docker Image Deployment to AWS ECR with GitHub Actions Building and pushing Docker images manually can help you understand the basics, but it’s not a good way to do things once projects …
Avishka Weeraddana · · 5 min read
Containers
AWS ECR for Beginners: How to Store and Manage Docker Images in AWS
AWS ECR for Beginners: How to Store and Manage Docker Images in AWS Many beginners learn how to build Docker images locally, but they are not always sure where those images should live once they move …
Avishka Weeraddana · · 4 min read
AI & ML
Prompt Injection in AI-Powered Applications
Prompt Injection in AI-Powered Applications How to Test Against Prompt Injection in AI-Powered Applications? Introduction Every AI system operates on instructions. But what happens when someone slips …
Navindu · · 8 min read
Security
How to Expose Internal Applications Securely Using AWS Verified Access (No VPN Required)
How to Expose Internal Applications Securely Using AWS Verified Access (No VPN Required) Imagine you need to securely expose an internal application to a specific group of users in your organization …
Manoj Fernando · · 6 min read
DevOps
AWS Amplify vs AWS CDK: What Are You Really Choosing?
AWS Amplify vs AWS CDK: What Are You Really Choosing? When you start building on AWS, the decision looks simple. You need authentication, APIs, storage, hosting, maybe a few backend functions. Then …
Bhathiya Ranasinghe · · 6 min read
Serverless
Trigger AWS Workflows from Incoming Emails Using Amazon SES
Trigger AWS Workflows from Incoming Emails Using Amazon SES Ever wanted to trigger a workflow based on an email sent to a specific recipient address? That’s exactly what we’re going to discuss …
Manoj Fernando · · 5 min read
Architecture
Core AWS Services You Must Know as a Developer
Core AWS Services You Must Know as a Developer AWS looks exciting from a distance. Then you open the console for the first time and see a long list of services, categories, and unfamiliar names. EC2 …
Binara Prabhanga · · 7 min read
AI & ML
What Is Amazon S3 Vectors? Use Cases, When to Use It, and Cost
What Is Amazon S3 Vectors? Use Cases, When to Use It, and Cost Amazon S3 Vectors is AWS’s managed service for storing and searching vector embeddings inside the S3 ecosystem. In simple terms, it …
Chameera Dulanga · · 8 min read
Serverless
Common Challenges of using Lambda Layers
Common Challenges of using Lambda Layers What are the Real-World Challenges of using AWS Lambda Layers and How to Fix Them? AWS Lambda Layers sound like a clean solution when you first hear about …
Pathum Jayaweera · · 8 min read
AI & ML
How to Build a RAG Knowledge Base with Amazon S3 Vectors and Amazon Bedrock
How to Build a RAG Knowledge Base with Amazon S3 Vectors and Amazon Bedrock Amazon Bedrock Knowledge Bases Explained: How Managed RAG Works on AWS Building AI for a business is not just about picking …
Chameera Dulanga · · 9 min read
Serverless
Handlebars with AWS Lambda Layers
Handlebars with AWS Lambda Layers A Practical Way to Manage Reusable Templates in Serverless Apps When you first start using Handlebars in AWS Lambda, everything feels simple. You write a template …
Pathum Jayaweera · · 9 min read
Frontend
Getting Started with Handlebars
Getting Started with Handlebars A Simple Way to Build Reusable HTML Templates When you need to generate HTML dynamically, things can get messy fast. Maybe you are building emails. Maybe you are …
Pathum Jayaweera · · 5 min read
Frontend
What is AWS Amplify?
What is AWS Amplify? Building a React app is the easy part. Then the “real app” requirements show up: Users need to sign up and log in You need an API You need a database You need file …
Rashindu Sithara · · 5 min read
Data
GSI vs LSI in DynamoDB
GSI vs LSI in DynamoDB Difference between GSI and LSI in DynamoDB When you start learning DynamoDB, one thing becomes clear very quickly: how you design your keys decides how well your table works …
Yugeesha Gomes · · 5 min read
Serverless
How to Use Lambda Layers with Amplify
How to Use Lambda Layers with Amplify Why AWS Lambda Layers Become Essential as Your Serverless App Grows When you first start using AWS Lambda, everything feels clean and simple. You write a …
Maleesha Nuwanthi Kolombage · · 3 min read
Data
Choosing the Right AWS Database: SQL vs NoSQL in the Cloud (RDS vs Aurora vs DynamoDB)
Choosing the Right AWS Database: SQL vs NoSQL in the Cloud (RDS vs Aurora vs DynamoDB) When you create a app , At first it’s simple: one app, one database. Then the system grows: a background …
Bhathiya Ranasinghe · · 4 min read
Security
Don’t Let Your Bucket Snitch: S3 Encryption Explained
Don’t Let Your Bucket Snitch: S3 Encryption Explained What are the Encryption Types in AWS S3? S3 is that one AWS service everyone uses because it’s easy to use. Upload file, get URL, move on …
Bhathiya Ranasinghe · · 4 min read
DevOps
AIOps with Amazon CloudWatch Investigations
AIOps with Amazon CloudWatch Investigations Hands-on, from alarm to root cause I’ve been using Amazon CloudWatch as a centralized logging and observability tool for quite some time now. One of the …
Manoj Fernando · · 10 min read
AI & ML
How I Built a Full-Stack Application Using Kiro, Kiro Powers, and MCP Servers
How I Built a Full-Stack Application Using Kiro, Kiro Powers, and MCP Servers A Chrome Extension Backed by an AWS Serverless Architecture As a Solutions Architect, one of my day-to-day tasks is …
Manoj Fernando · · 9 min read
Serverless
Don’t Make Lambda Call Lambda: Better AWS Patterns
Don’t Make Lambda Call Lambda: Better AWS Patterns A common moment in AWS projects goes like this: You have a Lambda function that receives a request, does some work, and then you realize there’s …
Bhathiya Ranasinghe · · 6 min read
Security
A Beginner’s Guide to AWS Security Groups
A Beginner’s Guide to AWS Security Groups If you’ve ever launched an EC2 instance and wondered “Why can’t I connect to it?”, chances are the answer lives inside AWS Security …
Bhathiya Ranasinghe · · 2 min read
Serverless
Understanding AWS Lambda Durable Functions
Understanding AWS Lambda Durable Functions From stateless functions to long-running workflows One of the most talked-about Lambda updates at re:Invent 2025 is Lambda Durable Functions. Until now …
Manoj Fernando · · 8 min read
Frontend
How to Build a Scalable, Real-Time Notification System in AWS Amplify
How to Build a Scalable, Real-Time Notification System in AWS Amplify Notifications are a core part of modern applications — they guide users, drive engagement, and deliver critical updates in real …
Ashan Dilsara · · 3 min read
Serverless
How to add Cognito User Data to DynamoDB | AWS Amplify
How to add Cognito user data to DynamoDB | AWS Amplify AWS Cognito is widely used to simplify authentication and authorization for web and mobile applications. It offers built-in features like: User …
Ashan Dilsara · · 3 min read
AI & ML
How to Build a Smart Personal Chatbot with Assistant API
How to Build a Smart Personal Chatbot with Assistant API Interested in building your own intelligent personal chatbot that’s fully under your control? With OpenAI’s Assistant API, you can develop …
Bhathiya Ranasinghe · · 3 min read
Serverless
AWS Lambda Monitoring — A Full Guide
Unlock the power of AWS Lambda Monitoring: learn about key metrics, invocation types, and the role of third-party tools for efficient serverless operations.
Manoj Fernando · · 10 min read
Data
AWS EBS vs EFS vs S3
AWS EBS vs EFS vs S3 How to Choose the Best AWS Storage Option for Your Project Amazon web services are widely used around the world for storage options. However, choosing a storage option is not …
Chameera Dulanga · · 3 min read
Architecture
How to Reduce AWS Cost with Spot Instances
How to Reduce AWS Cost with Spot Instances AWS EC2 Purchasing Options and When to Use Them AWS EC2 is one of the most used could services around the world. However, most new developers aren’t aware …
Chameera Dulanga · · 5 min read
Data
Managing Database Connections with Amazon RDS Proxy
Managing Database Connections with Amazon RDS Proxy
Chameera Dulanga · · 6 min read
Security
How to Secure Your AWS Account with AWS IAM
Secure Your AWS Account with AWS IAM and Multi-Factor Authentication
Chameera Dulanga · · 5 min read
Architecture
How to Choose the Best AWS Region for Your Project
How to Choose the Best AWS Region for Your Project 4 Factors to Consider When Selecting an AWS Region Today, AWS has become the most used cloud service provider among developers. Although there are …
Chameera Dulanga · · 4 min read
Serverless
How Does AWS SQS Work
How Does AWS SQS Work How AWS SQS Makes Asynchronous Request Handling Easy Amazon Simple Queue Service (SQS) is a fully managed message queueing service that allows you to decouple your applications …
Chameera Dulanga · · 5 min read
DevOps
AWS CDK — A Beginner’s Guide with Examples
AWS CDK — A Beginner’s Guide with Examples A better way to automate your AWS infrastructure If you have a production application running on any cloud platform, you must think of automating the …
Manoj Fernando · · 8 min read