At 23, Isaac is already jaded about software reliability - and frankly, he's got good reason to be. When your grandmother can't access her medical records because a username change broke the entire system, when bugs routinely make people's lives harder, you start to wonder: why do we just accept that software is broken most of the time? Isaac's answer isn't just better testing - it's a whole toolkit of techniques working together. He's advocating for scattering "little bombs" throughout your cod...
Jun 19, 2025•57 min
How do you retrofit a clustered data-processing system to use cheap commodity storage? That’s the big question in this episode as we look at one of the many attempts to build a version of Kafka that uses object storage services like S3 as its main disk, sacrificing a little latency for cheap, infinitely-scalable disks. There are several companies trying to walk down that road, and it’s clearly big business - one of them recently got bought out for a rumoured $250m. But one of them is actively tr...
Jun 05, 2025•1 hr 29 min
Java’s has been evolving faster than any 30 year old language has a right to do, and there’s probably no-one more pleased about it than my guest this week - Josh Long. He’s a Java & Kotlin programming, a JVM enthusiast in general, and an advocate for Spring, and he has chapters full of news about what’s been happening in Javaland over the past few years. Everything from new threading models to C interop changes, custom primitives to high performance computing and all the ways in which Java i...
May 23, 2025•1 hr 24 min
I’m joined this week by one of the authors of Apache Kafka In Action, to take a look at the state of Kafka, event systems & stream-processing technology. It’s an approach (and a whole market) that’s had at least a decade to mature, so how has it done? What does Kafka offer to developers and businesses, and which parts do they actually care about? What have streaming data systems promised and what have they actually delivered? What’s still left to build? – Apache Kafka in Action: https://www....
May 08, 2025•1 hr 12 min
Building a database is a serious undertaking. There are just so many parts that you have to implement before you even get to a decent prototype, and so many hours of work before you could begin working on the ideas that would make your database unique. Apache DataFusion is a project that hopes to change all that, but building an extensible, composable toolkit of database pieces, which could let you build a viable database extremely quickly, and then innovate from that starting point. And even if...
Apr 25, 2025•1 hr 32 min
Jupyter’s become an incredibly popular programming and data science tool, but how does it actually work? How have they built an interactive language execution engine? And if we understand the architecture, what else could it be used for? Joining me to look inside the Jupyter toolbox are Afshin Darian and Sylvain Corlay, two of Jupyters long-standing contributors and project-steerers. They’ve going to take us on a journey that starts with today’s userbase, goes through the execution protocol and ...
Apr 10, 2025•1 hr 29 min
Ever since we invented makefiles, the programming world has been wrestling with the problem of building software stacks reliably. This week we’re going to look at one of the most ambitious solutions available - Nix. Nix tries to do everything from invoking your compiler to installing your language, and even providing your operating system. But how does it work in theory, and how well does it work in practice? Joining me to discuss is Julian Arni, a Nix-enthusiast and creator of a build/test/depl...
Mar 27, 2025•1 hr 21 min
Graphite is a new image editor with an interesting architecture - it’s a classic UI-driven app, an image-manipulation language, and a library of programmable graphics primitives that any Rust coder could use, extend or add to. The result is something that you can use like Photoshop or Inkscape, or make use of in batch pipelines, a bit like ImageMagick. Joining me to discuss it are Keavon Chambers & Dennis Kobert, who are hammering away on building a project that’s potentially as demanding as...
Mar 13, 2025•1 hr 18 min
ReScript is a strongly-typed programming language that compiles to JavaScript, and that puts it squarely in competition with TypeScript. So why would a JavaScript developer choose to learn it next? What does it offer that makes it a tempting proposition? And how are the ReScript developers making life easier for anyone who wants to make the switch? To answer all these questions and more, I’m joined this week by Gabriel Nordeborn, one of ReScript’s compiler contributors. -- ReScript: https://resc...
Feb 20, 2025•1 hr 33 min
Trustfall is a library based on a simple question - what happens if we can query absolutely anything? If you could join REST APIs and databases with filesystems and dockerfiles? It’s possible in theory because those are all just datasources. Predrag Gruevski is trying to make it easy by building a universal query engine, with pluggable datasources, all in Rust. This week we dive into Trustfall to figure out how it works. How do you model nearly anything as a datasource? How do you make it easy t...
Feb 07, 2025•1 hr 16 min
Dimitris Kyriakoudis is a researcher, programmer and musician who's combining all three talents to build dedicated music hardware. Specifically a device called the µseq, which reads Lisp programs and uses them to drive synthesizers to make music. In this episode we go through the full platform that he's building, from soldering resistors to an RPi chip, up through writing a Lisp interpreter, to the design ideas that make Lisp a good choice for composing both software and music. – uSeq Homepage: ...
Jan 23, 2025•1 hr 35 min
If you want to build really large software systems well, you have to stop thinking of them as just software systems. Beyond a certain size, everything your software touches becomes part of the wider system. You’re part of the system, your users are part of the system, and every other employee & department & priority eventually forms part of that system. And that can make it incredibly difficult to make changes, or even to understand which changes will actually matter. That might be overw...
Jan 16, 2025•1 hr 50 min
To kick off 2025 we’re looking at Fyrox a game engine built in Rust, largely by one person - Dmitry Stepanov. For an individual project, it’s covered an incredible amount of ground, covering the rendering and animation features you’d expect from a game engine, with some features that might surprise you - like Rust scripting support with hot-reloading. As we dive into Fyrox, Dmitry explains what it takes to build a game engine, why he chose Rust (and why he’s happy with the choice), and how one p...
Jan 09, 2025•1 hr 44 min
Integration testing is always a tricky thing, fraught with problems setting up the right environment and attempting to control the system’s state. That’s particularly true when you’re dealing with a mix of software and hardware, and even worse when you don’t have control of what the hardware can do. This week I’m joined by Dave Lucia of TVLab’s, who’s building systems for testing television software at scale, and it’s a problem that needs a huge variety of techniques to crack it. He’s using came...
Dec 19, 2024•1 hr 16 min
Sam Aaron is the creator of Sonic Pi, one of the most unusual software platforms you’ll encounter. It’s a live-coding playground for making music. A tool that lets you write code that defines sounds and musical phrases, and build up a hole program that plays anything from a short bleep to a whole nightclub set. And Sam’s creator has been using it live for years, weaving drum & bass nights out of thin air, all driven by the Ruby-esque he writes. In this episode we go through Sam’s career path...
Dec 05, 2024•1 hr 50 min
Evan Czaplicki—the creator of the Elm programming language —joins me to discuss the state and future of Elm, the friendly, type-safe functional programming language. On many fronts Elm has been a huge success: it’s been popular with new and seasoned programmers alike; it’s helped push several language ideas into the mainstream; it’s been a key part of several successful software businesses and he even found himself employed as a kind of Language Designer in Residence. And yet, the material rewar...
Nov 28, 2024•50 min
This week we’re going to look at the most essential piece of firmware in a programmer’s toolkit - the brain. I’m joined by Chris Ferdinandi to explore what it’s like to be a programmer with ADHD. It’s an unusual topic for the channel, but the more I spoke to him, the more I wanted to know what coding is like when your brain is wired differently, how we can work more effectively with people with ADHD, and critically, how you manage coders with ADHD. And the answer to that comes full circle, in un...
Nov 21, 2024•1 hr 39 min
What have we learned from more than a decade of deploying microservices? Was it a good idea? Are we any better at figuring out what a microservice is, or where its boundaries lie? Does splitting things up create fragmentation problems? And is it too late to put the genie back in the bottle? This week we’re going to look at all these questions and more as we reflect on the lessons learnt from this big architectural idea. This interview was recorded live at GOTO Copenhagen, with two microservice e...
Nov 14, 2024•47 min
Pony is a language born out of what should be a simple need - actor-style programming with C performance. On the face of it, that shouldn’t be too hard to do. Writing an actor framework isn’t trivial, but it’s well-trodden ground. The hard part is balancing performance and memory management. When your actors start passing hundreds of thousands of complex messages around, either you need some complex rules about who owns and frees which piece of memory, or you just copy every piece of data and ki...
Oct 31, 2024•1 hr 13 min
This week we take a look at Bevy, a new game engine written in Rust. And in particular, we look at a core component of Bevy that has something to teach you even if you never write a game: its Entity Component System, or ECS. An ECS is an approach to managing complex systems with large numbers of moving parts, that takes some inspiration from the Relational Database world, and a little from Functional Programming to build something entirely unique and surprisingly high-performance. Joining us to ...
Oct 23, 2024•1 hr 18 min
Given how many languages have been written in C over the years, it’s not surprising to see new languages being written in Rust. What is surprising about this week’s guest is the domain he’s writing for: Computer Aided Design (CAD). Could Rust be sneaking its way into the CAD world too? Joining me to discuss the design and implementation of a CAD programming language is Adam Chalmers. He works at Zoo, developing KCL - a language that looks like JavaScript, runs on Rust, and offers users a seamles...
Oct 16, 2024•1 hr 23 min
For some kinds of application, there is no faster or cheaper way to build a user interface than in the terminal. Sure, it’s not going to suit every kind of user out there, but for those of us that are happy on the command line, rich Text User Interfaces (or TUIs) open all the exploration and discoverability benefits of a GUI are a fraction of the development time. This week we’re looking at a Rust TUI library with the excellent name ‘ratatui’. We’re joined by Orhun Parmaksız, one of the lead dev...
Oct 09, 2024•1 hr 6 min
Lustre is a web framework that takes a lot of inspiration from Elm, some from React, and a surprising amount from Erlang’s actor model, to provide a library that blurs the lines between executing on the client, or on the server. Support Developer Voices on Patreon: https://patreon.com/DeveloperVoices Support Developer Voices on YouTube: https://www.youtube.com/@DeveloperVoices/join – Lustre: https://hexdocs.pm/lustre/index.html Gleam: https://gleam.run/ Join the Gleam Community: https://gleam.ru...
Oct 02, 2024•1 hr 4 min
I’m always interested in what factors shape the design of a programming language. This week we’re taking a look at a language that’s wholly shaped by its need to support a very specific kind of program - audio processing. Anything from creating a simple echo sound effect, to building an entire digital instrument based on a 17th-century harpsichord. The language in question is Faust, and this week we’re joined by Romain Michon, who works on and teaches Faust, as we look at how it’s designed, what...
Sep 25, 2024•1 hr 18 min
This week we take a look at what you can do with a GPU when you get away from just using it to draw polygons. Agnès Leroy has spent most of her career programming, optimizing and converting programs to run on that oh-so-curious piece of specialised processing hardware, and we go through all the places that journey has taken her. From simulating the flow of fluids in hydroelectric powerstations, to figuring out how to make a new approach to encryption run fast enough to make it practical… – Becom...
Sep 18, 2024•1 hr 4 min
OCaml has one of the best-loved compilers available, and parts of it are surprisingly pluggable, so it’s not surprising that someone would eventually try to wed OCaml with JavaScript and the web browser. In fact, the ecosystem has gone further, and there are now a bevvy of options for people who want to write OCaml and run it in the browser, or want to write OCaml in the browser, or want to write something that looks like JavaScript but runs OCaml on the backend. Joining me to explore the OCaml-...
Sep 11, 2024•1 hr 27 min
Mapping is a hugely complex task to take on. Even if you moved as much of the data-management as you can out to 3rd-party services, you’d still have a tonne of work to do weaving together map tiles, routing information, GPS data, points of interest, search and more. And as if that wasn’t enough, you’d probably want that software to work on a whole range of platforms, so you have to build something that works on iOS, Android and more. It’s little wonder that the space is dominated by a few closed...
Aug 21, 2024•1 hr 1 min
The terminal might be the most used development tool in history. So it’s a little odd that it hasn’t changed that much in the decades since the terminal first came into being. Is the terminal a “completed” project? Or are there new ways to look at it that might make it even more useful? This week’s guest—Zach Lloyd—is convinced the terminal is ripe for a new approach that’s more than just a new coat of paint. And in this episode we dive into what that approach is, what he’s trying to do with the...
Aug 14, 2024•1 hr 8 min
A language’s AST—it’s abstract syntax tree—is nearly always a hidden implementation detail. It’s not treated as part of the language, but merely the intermediate step between parsing and compiling. But this week’s guest aims to flip that relationship on its head... Peter Saxton joins me to talk about EYG - an AST-first language that defines the fundamental capabilities first, and then stretches out from there to surface syntax and final execution. The result is something that can teach us a lot ...
Aug 07, 2024•1 hr 1 min
DuckDB’s become a favourite data-handling tool of mine, simply because it does so many small things well. It can read and write a huge number of data formats; it can infer schemas automatically when you just want to move quickly; and it can interface with most languages, run like lightning on the desktop or be embedded into a webpage. I’m a huge fan. But I’m not nearly as knowledgeable as this week’s two fans, Simon Aubury and Ned Letcher, who’ve just written a book on all the many ways you can ...
Jul 31, 2024•1 hr 8 min
