Hello 馃憢
I'm Alex O'Callaghan and this is my personal website where I write about software development and do my best to learn in public. I currently work at Mintel as a Principal Engineer working primarily with React, TypeScript & Python.
I've been leading one of our platform teams maintaining a collection of shared libraries, services and a micro-frontend architecture.
I'm from London and you can find me on a few different social media platforms:
Recent posts
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React design system library MCP
Published 路 3 min read
Exposing Storybook documentation to AI agents via an MCP server
Open sourcing our microfrontend React bridge
Published 路 1 min read
A library for rendering microfrontends in separate React trees
Reflecting on Enterprise Engineering Summit 2025
Published 路 9 min read
Key takeaways from the Enterprise Engineering Summit 2025
Package exports and eslint-plugin-import
Published 路 1 min read
Resolving package.json exports with eslint-plugin-import
Creating your own React design system analytics tool
Published 路 3 min read
Using react-scanner to implement an Omlet alternative
Upgrading React with micro-frontends
Published 路 2 min read
How to upgrade React incrementally across multiple micro-frontends
Delay using a federated module
Published 路 2 min read
Ensure federated module has loaded before using it
Using the experimental React Compiler
Published 路 4 min read
Trying out the React Compiler with React 19 beta
Using GitLab API to create a DORA metrics dashboard
Published 路 6 min read
Measure developer team productivity using deployment frequency and lead time for changes
Using TypedDict with invalid attribute names
Published 路 1 min read
How to use a TypedDict with item keys that aren't valid identifiers
Mock server-sent events (SSE) with msw
Published 路 2 min read
Mock Service Worker supports mocking SSE
Exclude node_modules with Webpack
Published 路 2 min read
Avoid bundling dependencies when building a library
Accessibility testing
Published 路 6 min read
Overview of approaches and tools for testing web accessibility
Dynamically load remoteEntry.js files
Published 路 2 min read
Control loading Webpack Module Federation remoteEntry.js files to improve peformance
Configure Boto3 endpoint_url
Published 路 1 min read
Use environment variables to point Boto3 at local services
Python TypedDict with Generics
Published 路 1 min read
How to define a Python type for a dict with generic values
Contract testing with OpenAPI & TypeScript
Published 路 3 min read
Validate contracts between backend services and frontend applications
Design system management
Published 路 4 min read
Processes and challenges in managing an adopted design system
Adopting a micro-frontend architecture
Published 路 1 min read
Supporting scaleable web application development with micro-frontends