I Presented at "Engineer LT & Networking Event supported by Kumamoto City & AWS Startup"

I presented at an engineer LT & networking event supported by Kumamoto City and AWS Startup, introducing and demonstrating our AI Agent Builder "Giselle" currently in development.

Trial and Error Using Japanese with Amazon Titan Foundation Model on Amazon Bedrock

A work log of three snags with Japanese on Amazon Titan / Amazon Bedrock, from model access to console garbling.

How to check the API Version currently used in Amazon CloudFront

Aggregating CloudTrail event history JSON with jq to see which CloudFront API versions my account still used.

[Amazon CloudSearch] [*Deprecated*: Use the outer message field] Validation error for field 'xxx': Invalid codepoint 1C

The Invalid codepoint 1C error on Amazon CloudSearch, resolved by stripping the u001c character from the JSON.

Sample code to log into Amazon Cognito and get Access Token [CLI curl edition]

A curl + jq CLI snippet for logging into Amazon Cognito and extracting the Access Token.

Amazon Cognito Practical Introduction Reference Information Summary

Reference material — an ebook and AWS Amplify's tutorial — for getting hands-on with Amazon Cognito.

Amazon Connect Contact Flow to Lambda Function JSON Request Sample

A JSON request sample for AWS Lambda test events when the function is triggered from an Amazon Connect contact flow.

Run docker system prune --volumes When Getting 'no space left on device' Error with Amazon ECS + Docker

Fixing the no space left on device error on Amazon ECS with docker system prune --volumes.

Amazon Elasticsearch Service 2.3 [script_exception] scripts of type [inline], operation [search] and lang [mustache] are disabled Error

Responding to the Mustache script_exception on Amazon Elasticsearch Service 2.3: drop Mustache or migrate to 5.1+.

Amazon OpenSearch Service Scale-up Does Not Cause Downtime

A record of scaling up an Amazon OpenSearch Service domain and confirming firsthand that it caused no downtime.

List of Databases Available in Amazon RDS Free Tier

A list of which Amazon RDS database engines are eligible for the AWS Free Tier and which are not.

[Amazon Redshift] TEXT type is converted to VARCHAR(256)

Amazon Redshift converts TEXT columns to VARCHAR(256) — a gotcha when coming from MySQL or PostgreSQL.

Amazon S3 AccessDenied Error with Only arn:aws:s3:::bucket Setting

Fixing an S3 AccessDenied error by adding the object ARN `arn:aws:s3:::bucket/*` alongside the bucket ARN.

Amazon S3 'A conflicting conditional operation is currently in progress against this resource. Please try again.' error

Waiting out the S3 `conflicting conditional operation in progress` error when recreating a bucket with the same name.

CORS Handling for Direct File Upload from Browser to Amazon S3

Resolving CORS preflight errors for direct browser-to-S3 uploads with an S3 CORS configuration JSON.

How to Configure Amazon S3 to Allow Uploads of Only Specific File Types (Extensions)

Restricting S3 uploads by file extension — and the extension-spoofing limitation of the approach.

Hosting a static website on Amazon S3

Hosting a static site on Amazon S3, both S3-only and in combination with CloudFront.

Amazon SES Initial Setup Reference Articles Summary

Go-to reference articles for the initial Amazon SES setup — sending limits, sandbox exit, and SPF/DKIM/DMARC.

Amazon SQS Message Limits per Queue

A quick summary of Amazon SQS's per-queue inflight message limits for standard and FIFO queues.

How to Set Up Custom Domain Email Addresses with Amazon WorkMail

Setting up custom domain email with Amazon WorkMail, forwarding, and the iOS Mail app on iPhone/iPad.

Setting Up Amazon WorkMail in iPhone Gmail App Configuration Steps

How to add an Amazon WorkMail account to the iPhone Gmail app over IMAP.

Amazon WorkSpaces Personal on Simple AD at small scale — setup, cost, and scaling paths

I set up a single-purpose Windows desktop on Amazon WorkSpaces Personal with Simple AD, for a small team that needs a browser and client certificates for a specific line of business. As of July 30, 2026, Simple AD is closed to new customers, and existing customers keep full functionality. This post covers the minimum setup, Tokyo-region monthly costs, what Simple AD gets you and where it falls short, the trade-offs of AWS Managed Microsoft AD and AD Connector, and the limits of WorkSpaces backup and restore, with citations to AWS official documentation.

Amazon WorkSpaces 'Unable to login' Error and 'Unhealthy' Status Troubleshooting

Recovering an Amazon WorkSpaces instance stuck in 'Unhealthy' status with an 'Unable to login' error via rebuild.

How to Set Up Windows 10 Environment with Amazon WorkSpaces

Standing up a Windows 10 environment on Amazon WorkSpaces because our admin team needed IE11.

Auth0 Custom Domain DNS Record Reflection Time is About 5 Minutes

Auth0's custom domain verified about five minutes after adding the CNAME record in Route53.

Restricting AWS ALB Access to CloudFront Only

Reference articles for restricting AWS ALB access to CloudFront-only traffic, with HTTPS pattern notes.

Comparison Information for AWS Batch and Job Services - AWS Batch, Lambda, ECS Task

Reference articles and decision notes for choosing between AWS Batch, Lambda, and ECS Task for batch jobs.

Letting AI Agents Use the AWS CLI Safely — A 2026 Defense-in-Depth Design That Disarms Any Single Credential

Hand an AI agent a shell and AWS credentials at the same time, and a single prompt injection can translate straight into deleted cloud resources or exfiltrated secrets. IAM Identity Center plus ReadOnlyAccess is the right starting direction. But ReadOnlyAccess is not 'read-only equals safe,' and tool-side deny rules do not survive adversarial evasion. Working from the premise that the only trustworthy enforcement boundaries are IAM and OS sandboxes, we layer defenses across authentication, authorization, execution, approval, and audit so that seizing a repository or a shell alone never reaches production.

How to register and use multiple AWS accounts with AWS CLI

Register multiple AWS accounts with `aws configure --profile` and switch between them via --profile.

AWS CLI Commands for Bulk Uploading Files to S3

`aws s3 cp` / `sync` commands for bulk-uploading files to S3, with --include / --exclude and --dryrun tips.

[AWS] aws s3 sync ./upload_dir s3://xxx --region ap-northeast-1

Fixing the `aws s3 sync` PermanentRedirect error by passing --region for the bucket's region.

Accelerating Prototyping with AI Coding Tools Using AWS Copilot CLI

Deploy AI-generated applications to ECS/Fargate quickly with AWS Copilot CLI. This article explains why this workflow is so effective for prototyping.

AWS Copilot CLI End-of-Support and Future Alternatives

AWS Copilot CLI's end-of-support is underway. Here's a summary of the confusing official announcements and the migration options being discussed in the community.

Why I Gave Up on AWS Copilot CLI for Preview Environments

I ran a PoC to build preview environments with AWS Copilot CLI and ended up abandoning the approach. Here's what went wrong and what I learned.

How to Configure AWS Default Security Group to Not Allow All Traffic (CIS 4.3 Compliance)

Stripping all rules from AWS default security groups across every Region to comply with CIS 4.3.

[AWS EC2] Instance Store - Ephemeral Disk (volatile disk) can be used for free

AWS EC2 instance store (Ephemeral Disk) is free to use, with the caveat that data is wiped on instance stop.

[AWS] How to Handle EC2 Instances Stuck in 'stopping' State

Force-stopping an AWS EC2 instance stuck in the 'stopping' state until it transitions to 'stopped'.

About AWS EC2 instance-specific network bandwidth and bandwidth guarantee

Measured per-instance EC2 network bandwidth references and confirmation that AWS does not guarantee it.

How to Renew and Repurchase AWS EC2 Reserved Instances

Notes on renewing and repurchasing EC2 Reserved Instances after they expire, since they aren't auto-renewed.

AWS EC2 instance selection meeting Wowza Streaming Engine minimum recommended specifications

Choosing AWS EC2 instance types that meet Wowza Streaming Engine's minimum recommended specifications.

AWS ECS Exec Sample Script for /bin/sh Login

A sample script for one-shot /bin/sh login into a running ECS task container via AWS ECS Exec.

AWS ECS Task Error: 'Unexpected EC2 error while attempting to Create Network Interface in subnet 'subnet-xxx': InsufficientFreeAddressesInSubnet'

An ECS Task InsufficientFreeAddressesInSubnet error caused by leftover old tasks consuming subnet IPs.

AWS ECS Scheduled Tasks Management Method (ecschedule Edition)

Managing AWS ECS Scheduled Tasks with ecschedule for GitOps-style scheduling.

How to Create Access Keys for AWS IAM PowerUser

Two approaches to letting an AWS IAM PowerUser create AWS CLI access keys.

How to check the list of AWS Lambda default environment variables

Listing AWS Lambda's default environment variables via docs and a Node.js process.env dump.

AWS Lambda Sample Code to Delete Specific Files Uploaded to S3

A sample AWS Lambda function that deletes S3 objects whose ContentType is text/html.

Deploying to AWS Lambda with Serverless Framework

Installing Serverless Framework and deploying to AWS Lambda using the aws-nodejs template.

Steps to set up AWS Lambda local development environment [Serverless Framework Edition]

Setting up AWS Lambda local development with serverless-offline and companion plugins.

Upload from AWS Lambda function to S3 [Serverless Framework Edition]

Uploading HTML from an AWS Lambda function to S3, with Serverless Framework handling bucket and IAM setup.

[AWS Lambda] We recommend npm install serverless --global to reduce node_modules file size

Global-installing Serverless Framework cut the AWS Lambda deployment .zip by about 10 MiB.

Application for load testing of API / Web services built on AWS

When AWS-side approval is or isn't needed for load testing APIs or web services on AWS.

AWS Multi-Tenant SaaS Architecture Beginner's Guide Summary

A curated list of beginner resources for AWS multi-tenant SaaS architecture.

[AWS] Moving from Private Subnet to Public Subnet to Reduce NAT Gateway Costs

How I reduced NAT Gateway costs by moving ECS Scheduled Tasks from a private subnet to a public subnet.

Applying Credits to Accounts Under AWS Organizations

AWS Support's answer on when AWS Activate credits do and do not apply to accounts under AWS Organizations.

Password Reset Required for First Root Account Login After Creating New Account in AWS Organizations

How to perform the initial root login on a new AWS Organizations member account by resetting the initial password.

AWS Account Management Policy Comparison - AWS Organizations vs IAM Switch Role

Pros and cons of AWS Organizations vs IAM Switch Role for managing multiple AWS accounts.

How Much AWS RI and Savings Plans to Buy — A Strategy That Avoids 100% Commitment

Buying 100% coverage is not the right answer for RI and Savings Plans. Starting from hourly, non-rolling commitments, here is a practical strategy for committing only to your floor, incrementally.

HTTPS Support with AWS S3 + CloudFront + Route53

Serving an S3 static site over HTTPS by adding CloudFront in front of an S3 + Route53 setup.

[AWS] List of S3 Regions

A quick-reference table mapping Amazon S3 region names to their endpoints and protocols.

Cost Comparison Between Amazon S3 Standalone and S3 + CloudFront Configuration

Comparing costs and trade-offs between S3 standalone and S3 + CloudFront to decide which fits your workload.

Reference Information for Developing SaaS on AWS

Reference links — SaaS Lens and the builders.flash SaaS on AWS series — for developing SaaS on AWS.

A Design Blueprint for AWS Commitment Discounts in 2026 — Layering Strategy After Database Savings Plans

AWS cost optimization has one cardinal rule: shrink first, then commit. With Database Savings Plans (December 2025) at the center, this post lays out a three-layer stacking design (Compute SP for general compute, Reserved Instances for stable data tiers) through the lens of application order, provisioning math, and multi-account governance. The 2026 question is not how to chase the deepest discount, but how to design financial flexibility that never blocks modernization.

Using DefaultCredentialsProvider Instead of ProfileCredentialsProvider [AWS SDK for Java]

Switching AWS SDK for Java from `ProfileCredentialsProvider` to `DefaultCredentialsProvider` and its benefits.

AWS S3 Sample Code for credentialProvider Considering IAM Role [AWS SDK for JavaScript]

TypeScript sample for an IAM-role-aware S3 credentialProvider setup, including a minio-compatible variant.

[AWS] Sites to Check if Each Service is Running

A short memo of sites for checking whether AWS services are currently up and running.

AWS Session Manager Plugin Installation Method [macOS Monterey 12.4 Edition]

Working install steps for the AWS Session Manager plugin on macOS Monterey 12.4.

AWS Support Cases May Be Faster in Japanese Than English — Notes from a 5-Day Wait on SES Production Access with the Basic Plan

An Amazon SES Production Access request I filed in English sat with zero response for 5 days. Filing a fresh case in Japanese was what actually got it moving. Here is the field playbook for when a Basic-plan support case stalls, and the counter-intuitive lesson that English is not always the faster language for AWS Support.

When using CDN, CNAME management with subdomain is better for SEO

For SEO, point a custom-domain subdomain at your CDN with a CNAME instead of using the raw CDN URL.

CDN Implementation Proposal

A CDN proposal covering the basics, trade-offs, and choosing between CloudFront and Fastly.

Detecting Terraform Vulnerabilities with Checkov: An Insecure vs Secure Comparison Demo

IaC security should be verified before you apply. Checkov lets you detect Terraform vulnerabilities through static analysis. Using five AWS resources (S3, Security Group, RDS, IAM, CloudTrail), this demo reproduces the journey from 37 FAILEDs to 111 PASSEDs in a public repository.

How to publish a static website with custom domain using Amazon CloudFront + S3 + Route 53

Publishing a static site on a custom domain with CloudFront + S3 + Route 53, including OAI and HTTPS setup.

Participated in AWS CTO Night and Day 2023

A record of attending AWS CTO Night and Day 2023 in Fukuoka, with links to attendee recaps.

Participated in AWS CTO Night and Day 2024 in Kanazawa

A record and reflections from attending AWS CTO Night and Day 2024 in Kanazawa.

Solution for ECR Connection Error After Changing VPC Settings with S3 Endpoint on AWS

Notes on resolving ECR 403 Forbidden errors after VPC changes, focused on the S3 gateway endpoint that ECR relies on.

How to Investigate Amazon ECS Task Stop Reason 'Essential container in task exited'

How to investigate ECS tasks stopped with 'Essential container in task exited' via the Console and AWS CLI.

Email Delivery Systems: Set up SPF and DKIM Without Fail

Why SPF and DKIM are must-configure for email delivery systems, with setup docs for Amazon SES, SendGrid, G Suite, and Zendesk.

Email Configuration Check Services ~ SPF, IP Reputation

Post-setup email checks: MxToolBox for SPF and Cisco Talos for IP reputation after configuring AWS SES.

Using IAM Roles in GitHub Actions Without Passing AWS Credentials Directly

A reference article on assuming AWS IAM Roles from GitHub Actions without long-lived credentials.

GraphQL Introduction Articles for REST API-Minded People

GraphQL introduction, use cases, and API design articles I read as a REST-minded engineer to get up to speed.

[Heroku] Runs on Amazon EC2 North America Region, Response Time from Japan is Around 300ms

A 2012 snapshot noting Heroku ran only on Amazon EC2 US East, with roughly 300 ms response times observed from Japan.

Heroku Meetup #18 Connect! Participation Report #herokujp

Trip report from Heroku Meetup #18 Connect! — AWS-to-Heroku migration, Heroku Connect, and Kafka on Heroku.

How to Fix Internet Explorer 11 (IE11) Showing Blank Pages on Amazon WorkSpaces

Fix blank pages in IE11 on Amazon WorkSpaces by turning off IE Enhanced Security Configuration.

Sample Module Code for Getting Amazon Cognito Access Token with k6 Load Testing Tool

Sample k6 code that gets an Amazon Cognito access token in setup and runs authenticated load tests.

Practical Introduction to Load Testing

A quick reading list for getting started with load testing — voluntas's intro gist and an AWS-focused book.

Picking an OSS Alternative After LocalStack Was Archived — A Comparison of MiniStack, Floci, kumo, fakecloud, and moto

LocalStack's OSS repository was archived and the Community Edition image was rolled into an auth-required unified image, leaving many teams who had built their CI/CD and docker-compose flows around it scrambling for a replacement. This post lines up the newcomers (MiniStack, Floci, kumo, fakecloud) and the durable test-side tools (moto, ElasticMQ, S3Mock, DynamoDB Local), compares them on license, service coverage, and migration cost, and maps each candidate to a workload.

Mastodon usage guide, server setup, and useful tools summary

Curated references on Mastodon usage, server setup on Sakura Cloud / VPS / AWS, and useful tools.

Migrating Domain Registrar from DNSimple to Amazon Route 53

Steps for migrating a domain registrar from DNSimple to Amazon Route 53.

Creating Infrastructure Diagrams with Miro

Where to grab AWS, GCP, and Azure icon assets for infrastructure diagrams in Miro.

MySQL Query to Check Data Size of DB and Tables

SQL queries to check MySQL DB and table sizes for Aurora storage cost estimation.

On-Premise vs Cloud Decision Criteria

Decision criteria between on-premise and cloud from a cost perspective, with Dropbox's AWS repatriation as a case study.

Comparing online storage services for backup purposes

Comparing Google Drive, Dropbox, OneDrive, MEGA, S3, and Backblaze B2 for personal backup on price and usability.

[Python] I Tried the Amazon Product Advertising API

Calling the Amazon Product Advertising API from Python and searching books by keyword, with signed request code.

[Character Encoding] UnicodeDecodeError: 'ascii' codec can't decode byte 0xe4 [Python]

Resolving a UnicodeDecodeError from the Amazon API call by switching the keyword argument to a Unicode string.

[Ruby on Rails] How to Configure Amazon SES (Simple Email Service)

Setting up Amazon SES over SMTP in Rails 3.2.5 with the aws-ses gem.

Held Book Club for 'Introduction to Modern Applications with AWS: What Serverless, Containers, and Microservices Can Do'

In-house book club notes on 'Introduction to Modern Applications with AWS' — a solid overview of AWS service choices.

How to Create AWS Lambda Layers with node_modules and Add Them to Lambda Functions

Build node_modules-bundled Lambda Layers with Docker and the AWS CLI, then attach them to a Lambda function.

Reading Notes: 'Amazon Web Services Load Testing Introduction - Understanding How to Draw Out Cloud Performance' by Narikawa Taruha

Reading notes on 'Amazon Web Services Load Testing Introduction' — a starting point for load testing on AWS.

Data Transfer from Amazon S3 to BigQuery

Gotchas from moving data from Amazon S3 to BigQuery via the BigQuery Data Transfer Service.

How to fix Task timed out after 6.00 seconds error [Serverless Framework][AWS Lambda]

My Lambda function hit the default 6 s timeout, so I bumped the `timeout` value in `serverless.yml`.

How to delete all services deployed with Serverless Framework

Cleaning up leftovers from `serverless remove` — deleting the S3 Bucket, DynamoDB Table, and CloudFormation stack from the AWS Console.

[Linux] Sample Code to Retry Shell Commands Until Success

A `/bin/sh` snippet that retries a command with back-off until it succeeds.

[ssh] How to fix 'Warning: the RSA host key for 'server_name' differs from the key for the IP address 'xxx'

How I cleared the ssh RSA host key mismatch warning by deleting the offending line from known_hosts.

Participated in Startup CTO Night & Day 2025 Powered by AWS

I participated in Startup CTO Night & Day 2025 Powered by AWS. This year, I had the opportunity to present at the 'Shikujiri! CTO Dojo' session, which was a great experience. While much of the content was off-the-record and cannot be shared in detail, I wrote this article as a record of my participation.

Speaking at 'Startup Meetup Kumamoto @ XOSS POINT.'

Speaking at Startup Meetup Kumamoto @ XOSS POINT. about a kindergarten search chatbot on Amazon Bedrock.

Detecting Terraform Misconfigurations with Trivy: A Comparison Demo with Checkov

Following our Checkov demo, we scanned the same Terraform code with Trivy. Checkov found 37 issues; Trivy found 27. Where does the gap come from? We compare severity classification, IAM wildcard handling, and check ID systems using actual scan results.

What's the Recommended VPS for Hosting WordPress for US Audience?

Comparing Amazon Lightsail, DigitalOcean, and Linode for hosting WordPress targeted at a US audience.

xk6-cognito verification -> Got errors and it didn't work

Trying the xk6-cognito k6 module ended in a context.Context conversion error — here's the reproduction and known issue.

How to send emails from Zendesk using G Suite group custom domain email addresses

Send Zendesk email from a G Suite group address on your custom domain, with Route 53 and SPF setup.