Hi, thanks for visiting!

My name's Sam Kelleher, and I am a Senior Full-Stack Web Developer / Software Architect based in London. This website mostly contains a sample of work from my portfolio, tips, and best practices for building web applications.

Newest Standard Posts

Local first: Travel Itinerary Planning App

Local first: Travel Itinerary Planning App

This is a local first app (an app without a backend) for tracking a users travel, so think hotel bookings, reservations, flights and trains. Then there is the various loyalty programs offered by airlines, and keeping track of each flight and award. Putting that information into a manageable timetable and tracking the associated costs and expenses. These are the issues I addressed to improve when making this offline first app. Read more...

Crypto App using SwiftUI

Crypto App using SwiftUI

In my recent day-to-day work, I don't come into much contact with writing vanilla iOS apps directly. Despite being quite knowledgable in mobile app development, and the Swift programming language, I don't use these skills often. For this reason, I often in spare time (such as waiting at airports) write small apps, and review tutorials for using the latest advancements in programming languages like Swift, and the associated tooling like Xcode. Read more...

In-house tooling: Powerful CRM Tooling

In-house tooling: Powerful CRM Tooling

Building a product for a business is nothing without an empowered team behind it; equipped with capable tooling to enable them to do their best. As part of a project to build a customer loyalty platform, the business also needs tooling to view sales data, view customer profiles, their loyalty history, see a unified view of communications, their 'touch point' activity with the business; as well as the ability to modify and control the various bells and whistles of the platform. Read more...

MacroMealPrep App

MacroMealPrep App

I created this as a side project in my spare time as a way to plan ahead the food I would need to eat in a given week. The saying goes, "if you don't plan then you plan to fail". This goal of this app is different to other apps like MyFitnessPal which are geared around weight loss, and don't allow you to make plans in advance. Merely, they just track the food you eat, as and when you eat it. With my app, I wanted to put advance planning first, meaning, during the week, I would not need to spend mental energy thinking about what I should eat, when, or where. Read more...

Whitelabel Retail + In-Store Functionality

Whitelabel Retail + In-Store Functionality

Eastern Mountain Sports is a physical and online sportswear retailer located in the north-eastern United States. Following an acquisition of EMS by my employer, Sports Direct International, the Research and Development arm of SDI had the opportunity to re-platform their e-commerce property from Demandware (now known as Salesforce Cloud) to something of our own choosing. Reaction Commerce is a startup of a few years based in Santa Monica, California. They build a Meteor based, semi headless e-commerce platform called Reaction, with a GraphQL API and plugin architecture at its core. Read more...

Ultra fast response times serving static files with WebAssembly Workers

Ultra fast response times serving static files with WebAssembly Workers

With trends moving to Serverless or Function-as-a-Service we've started building our web servers from instances of Express running inside Docker containers, to "functions" that instead run on managed infrastructure, responding to each request as they arrive. Many cloud providers supply this type of system which is fast, cheap, and very easy to maintain as all you have to do is upload your functions. Cloudflare in particular innovate further by replicating your worker to every edge node in their network, drastically limiting CPU + memory time, in exchange for response time as each worker 'instance' is located physically close to users. With previous approaches, worker instances were usually just located in a single region with redundant zones only; thus requiring a load balancer to be setup which is also not simple. Read more...

React Isomorphic eCommerce Retail Experience

React Isomorphic eCommerce Retail Experience

A new Isomorphic React website that I describe as dumb, in that very little processing is done in storefront itself, instead, transactions are handed off to the API wherever possible. The goals that the website had to achieve was basically to not be Demandware. It should be uncoupled and agnostic from the datasource in all instances. It should be extremely fast, reliable, simple, and also customisable and theme-able. An anonymised responsive webpage is generated dynamically for each request, utilising significant in-app caching, and is frontend on the edge using Cloudflare which means the consumer gets a very fast and rapid render of the page, so even if the script takes a load to kick in on their browser, it happens before they begin to start interacting with the page. Read more...

Auto-Generated Release Notes in Docker for Webpack

Auto-Generated Release Notes in Docker for Webpack

This is an inline tool that, when used in a Continuous Deployment workflow can automatically generate full featured release notes when run as a Docker mounted command In particular, it is useful for Webpack build JavaScript projects that have outputted a stats file, as this tool is able to consume the data, and integrate relevant parts of it into the final release notes. The full release notes, and formatted bundle information relating to the Webpack build, are uploaded to GitHub and created as a release on the commit that generate it. It's able to compare the last prior release with the current one, and highlight important performance information, such as changes in the number of bundles, their chunk names, and their respective sizes; which are all relevant if you want to maintain an ongoing trend of light client releases. Read more...

React + Redux Administrative Panel SPA

React + Redux Administrative Panel SPA

A sleek and comprehensive single page application built using the latest React and Redux technologies. This application had to include comprehensive user permission capabilities including user management, data manipulation, search, a detailed analytics visualisation section, image editing with drag and drop.There was a lot to do, but with just a few tweaks the app is lightening fast to startup and initialise. One of my personal favourite things about Redux, and the flux pattern in general, is the predictability. As such, this project was one of with the fewest detected defects. Since what is on the screen is guaranteed to be generated by the data in state, any glitches or unexpected behaviour could be traced instantly using the Redux Time Machine. Read more...

Responsive Isomorphic Website with React, GraphQL, CSS Modules

Responsive Isomorphic Website with React, GraphQL, CSS Modules

Had the privilege of creating the public facing website for the company I work for, Blink. Since it's another greenfield site and React was strongly adopted by the company, it made a lot of sense to also construct the website using React.The content had to be editable by the marketing team, but since the parts of the website don't fit in a classic page type system that is popular on Wordpress, I integrated a third part content management platform, Contentful. Since the website would be Isomorphic, I had a Node Express server at my disposal, so I immediately got to work adding a GraphQL API that would be responsible for serving up the various strings and images stored in the CMS for the specific elements of these bespoke built pages. Read more...

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