ocgtk development update: June 2026
Development update for ocgtk (a set of GTK4 bindings for OCaml), including upcoming support for signals and interfaces, expanded GLib type coverage, and packaging improvements to support other operating systems.
Chris Armstrong
Development and tech musings. I'm a full-stack developer working with serverless architecture on AWS with TypeScript and React
Latest posts
Emulating inheritance without classes
The O in OCaml is for its object-oriented extension, but I needed a way to emulate the constraints of inheritance without it. This raised some interesting design questions about how to do it using only the core ML language.
Tackling multiple namespaces in ocgtk
Even though I was focussed only on generating GTK bindings for OCaml, I still had to consider all the other libraries it depends on.
A day with Claude and OpenTelemetry
The "glue" part of OpenTelemetry instrumentation is where each vendor hands you a ball of sticky tape and tells you to install it in your environment.
ocgtk preview1 now on opam
ocgtk, a set of GTK4 bindings for OCaml, is now available on opam as preview1 release
Introducing ocgtk: GTK4 bindings for OCaml
Introducing ocgtk, a new set of GTK4 bindings for OCaml generated from GObject Introspection data.
Sydney AI Engineering Meetup talk - A field report on using LLMs with a little-known language
Last night I presented a talk at the Sydney AI Engineering Meetup on using agentic coding loops with lesser known languages and less-capable models, of which you can find the videa and slides linked
Losing control of the code
Free AI credits, a side project picked on a whim, and a false sense of progress left me with a codebase I couldn't read. Losing control was necessary to understand how to get it back.
What would make OCaml serverless ready?
What role does programming language choice make when targeting serverless environments, and how does OCaml stack up against popular serverless development languages? What would it take to make OCaml your primary development language for serverless?
We build our own tools
Is it unusual as developers that we create software but also the software that helps us build?
Instrument your build pipelines to level up your DevOps maturity
Observability is not just about production systems. Leaving critical engineering infrastructure like build pipelines uninstrumented makes it hard for your organisation to identify development bottlenecks and release regularly.
ICFP 2025 Wrap-up
Wrap-up on my time at the ICFP '25 conference in Singapore
Update on smaws development - October 2025
ICFP, smaws gets multiple scheduler support
Update on smaws development - September 2025
Update on smaws, an AWS SDK for OCaml
OCaml cross-compilation: an experiment
OCaml has no official solution to cross-compilation, with many disparate options developed for different use cases. In this article I describe my own experiments with cross-compilation and attempts to make it easier to get started and maintain.
PPXLib is not just for transforming code
ppxlib is usually just thought of as a tool for transforming OCaml code, but it can be used to generate new code too.
Keeping it small: helping the compiler to remove unused code in OCaml
OCaml has some facilities for eliminating unused code - I explore what it can do, and how you structure your code to take advantage of it
What we didn't learn from the past
Nostalgia for old operating systems and applications is misplaced. We don't need to return; their failures are the lesson learned.
Dead code elimination dead end: OCaml doesn't tree-shake
My (unsuccessful) investigation into removing unused code from the compiled output of OCaml, including all the web archeology and deep-dive into how native binaries are formed.
Stack splitting with AWS SAM: Escaping the resource limit for API functions
An AWS SAM application with a lot of APIs can still hit the CloudFormation stack resource limit. This guide shows you how to approach stack splitting for such an application.
Using IAM Identity Center through the Command Line
How to do basic administration tasks, like add users to groups, with the IAM Identity Center when managing multiple AWS Accounts and user access
Storybook 7 - Visual Regression Testing
Storybook 7 has changed the visual regression story, no longer relying on storyshots. This is how to get a visual regression workflow up and running with the new test-runner functionality.
Unit testing OCaml code with ppx_expect: some notes
Some notes on using ppx_expect to unit test
What I'm working on: resource references in ocaml-cfgen and IAM policy generation
ocaml-cfgen gets resource reference, IAM policy generation and what's next
What I'm working on: ocaml-cfgen
A new project I'm working on to generate CloudFormation templates from OCaml bindings, and the problems that motivated its creation
CSS works against maintainability
The design of CSS does not make styling HTML more maintainable - in fact, it seems to actively work against it.
API Mismatch: Why bolting SQL onto noSQL is a terrible idea
Database ORMs like Prisma can make managing data access layers to SQL databases much easier for developers, but if used with a database that has dramatically different semantics and API, the benefits of abstraction are lost and turned into a maze of horrors
Observability: What to instrument?
It takes time to build up a sense of what to instrument to get the most out of your investment in observability, and it pays to know what primitives you have at your disposal and how to use them effectively.
Package your NodeJS Lambda functions individually with esbuild for faster cold-start times
Learn about packaging your NodeJS-based AWS Lambda functions with esbuild for improved cold start times and reduced deployment package size
Setting up a new Reason project
Starting a new Reason project for native development is relatively straightforward. We run through the basics.
Type-safe APIs with ReScript
Learn how to build a type-safe JSON API in ReScript that runs on AWS Lambda
Using Rescript to build applications on AWS Lambda
Learn how to use ReScript to write and deploy a simple AWS Lambda application
Retry, Timeout and Cancel with fetch()
Add retries, timeouts and cancellation to your fetch() calls without including another HTTP library
Building successful transactional applications on DynamoDB
Building transaction applications on DynamoDB can be a challenge - here is a few tips I've learned to ensure it is successful
When to use DynamoDB
When would you use DynamoDB? A quick run-down of the advantages and disadvantages
What is AWS Control Tower? A quick overview
Managing multiple accounts is a headache on AWS, especially when you're trying to maintain best practice compliance and when operations isn't your day job. AWS's new Control Tower service makes it much easier to provide governance and monitoring of your multi-account environment, automating the deployment of centralised audit logging, account guardrails and ensuring consistent base configuration…
Testing node-fetch with jest in TypeScript
Setting up a test of code that uses node-fetch with jest and Typescript
Setting up API Gateway CloudWatch Logging for your AWS Account
Setting up CloudWatch Logging for your API Gateway is painful - here's a script to make it easy
Understanding Amazon Cognito
Understanding what is Amazon Cognito and how it is used
Run your own teleconferencing server with Jitsi on EC2
Running your own Jitsi instance on EC2 with an easy-to-deploy CloudFormation solution
dynaglue: Getting Started Guide
A guide for getting started with dynaglue
Announcing dynamodb-csv-export-import
Annoucing dynamodb-csv-export-import, a utility for importing the CSVs generated by the AWS DynamoDB Console 'Export to csv' feature
What is this
An overview of this blog