The Amazing Benefits of Exercism

A couple of months ago, a good friend at work (@rodeoclownII) sent out an email (or blog, or Slack message, or something) about exercism.io. It’s a cool little website for practising programming in various languages (currently about 45) by implementing koans, or small exercise problems.

I’ve been working through the Kotlin problems since the start of the year and I’ve found it super useful, so I thought I’d write this quick blog to recommend it to others.

Why I like exercism.io so much

Actor Anthony Hopkins seemingly performing an exorcism with the words "Back to hell, demon!" Probably unrelated to exercism.io

Just to be clear, we’re not talking about this kind of exorcism.

The most obvious benefit of this site is the opportunity to practise using different elements of the Kotlin language and standard library. Being challenged to solve problems which you might not necessarily come across during day-to-day work can lead you to discover parts of Kotlin that are really useful but which you otherwise might not have found a need to go looking for. Also, the problems are all implemented in a test-driven way, which feels very natural for me as a long-time practitioner of Extreme Programming/TDD. Continue reading

Memories from 10 years at a startup

Black and white photo of four kids on an outdoor cubby houseI recently notched up ten years of working at Tyro Payments, a tiny little payments startup that I joined in late 2006 when it had about 20 people, and which is now Australia’s most successful fintech venture, Australia’s newest bank, and is fast approaching 400 staff.

Here’s a collection of some of my most vivid recollections from so far in this fantastic journey.

Getting Hired

I remember… when the recruiter for Tyro said he had a finance role, and I reiterated to him that I wasn’t going to take any job in finance. He back-pedalled, convinced me it wasn’t really a finance company and I really had to go meet them. I was reluctant, but I went along because I wanted to be in his good books.

I remember… the hook for me was one of the founders – Peter Haig – drawing the architecture they were building and me thinking 1) this is very cool and 2) this guy is very smart.

I remember… I plucked up the courage to ask where the company got its money from after three years of runway with no customers, and the founder was completely unfazed that a software engineer would ask such a question.

I remember… asking whether they really wrote tests before making any changes to the system, even to web pages, and Matt Milliss saying, “To be honest, I can’t believe how much code I wrote without tests before I came here, and how many bugs I must have created that no one has found yet.” It was a statement that shook my confidence in myself as an engineer and made me want to learn from this mature group of people that seemed to have a bunch of things figured out that most other software teams were still battling with.

I remember… I was so concerned about whether or not I’d enjoy pair programming that I asked for extra time to think about the offer.

I remember… discussing with my wife what would happen if I joined a startup and it went under and how long we thought we could survive on her salary if it took a while for me to find another job.

Startup Land

Hikers starting up a long steep climbI remember… on my first day I spent the morning pairing with Mark, who patiently spent the whole time telling me about the architecture of the system. We swapped pairs at lunchtime and I stayed on the task. My new pair, Geoff, asked me what we’d done in the morning and I said, “Nothing, we just talked about the system.” He looked at me strange, shook his head, and said “Right”. Then he changed a test, I changed the implementation to make it pass, and within half an hour we’d checked my first change into the mainline.

I remember… for the first six months having to explain to people that I worked at a company called MoneySwitch, watching their confused and concerned face, and preparing to explain that it wasn’t a money-laundering operation.

I remember… in the first office I worked in, we had no dishwasher and everyone was on a washing up roster, including the CEO.

I remember… that first office got really hot and the building aircon sucked. We had a single portable air conditioner… which was dedicated to the server room. On hot days we’d open a few windows and try to create a cross-breeze with a fan or two, but mostly we’d just sweat it out and keep going, or take a break for slurpees.

I remember… the whole Dev team – all 12 of us – used to go out to the mall to eat lunch together almost every day. There was no room to eat lunch in the office.

I remember… that the fortnightly demo involved the whole company – all 20 of us – cramming into the 3m x 10m board room and sharing a single case of beer.

I remember… when we moved to occupy two levels of 125 York St (now home to Blue Chilli) and it felt like we’d been upgraded to The Ritz.

I remember… when, less than 6 months in, my team leader proactively had my salary adjusted up because she thought Tyro had unwittingly hired me cheap based on my experience. It was an eye-opening example of how serious Tyro was about living out the company’s values.

Engineering Feats and Follies

Sydney Harbour Bridge being constructedI remember… when Ricky Yim and I got to do a spike of making a POS and an EFTPOS terminal integrate by communicating over the internet and through our system instead of over a serial cable and we got it working in a couple of days – probably Australia’s first “cloud” POS integration.

I remember… we discovered two years later that a demultiplexer in our POS integration was using a single thread to process all requests from thousands of clients and had only just started to struggle with that load. We bought ourselves about another decade of scaling by changing a config file.

I remember… I “refactored” an API between two systems that had some poorly-named fields, and a week later we mysteriously stopped paying merchants for the cashout they’d given customers. And we only knew about it when they called to complain. No one ever asked who’d made this bug happen, and instead the team had a conversation about how to stop it from happening again.

I remember… us being (equal) first to be accepted to be an acquirer for Medicare EasyClaim online claiming, and the excitement and enthusiasm of being part of building this huge new thing that was going to help improve the country’s public health system. Today, Tyro processes more than half of all the claims on the EasyClaim system, despite four other major banks offering EasyClaim services.

I remember… a litany of small tools that I built at home and brought to work: Canopy, the Maven multi-project build UI; Mini-Rest, a tiny Servlet library that forced people to use proper REST semantics; SodaTest, a Scala-based integration testing framework intended as a replacement for FIT; “Who’s the Expert?”, a smart contributor scoreboard for Bitbucket Server; and probably heaps of others I’ve forgotten.

I remember… relishing the opportunity to be part of rebuilding the accounting system from scratch to fix its performance and maintainability issues. It’s still humming along half a decade later!

I remember… half-jokingly whinging to my boss about how it was coming up to 12 months since I’d been working on nothing but the accounting system, and I might have to find another job if I was going to be doing nothing but accounting for the rest of my life. He moved me off that piece of work a week before 12 months.

Levelling Up

Red and white mushroom, like one used in the Mario game for a power upI remember… when I and three others were pulled aside to a corner of the office (we didn’t have any meeting rooms) to meet Mike Cannon-Brookes. He was considering joining our board but he wanted to meet (and grill!) some of the senior Engineering staff first so that he could check whether we were as good as our management team said we were. He joined, so I guess we did okay.

I remember… asking if I could take on a few more responsibilities because I was bored and, instead of being given an extra job or two, I was told I’d be made an Engineering Lead.

I remember… first getting involved in interviewing, not having any idea what I was doing, and feeling the weight of making decisions that would significantly affect other people’s lives and the future of the company.

I remember… we used to ask people to write a function on a whiteboard to calculate factorials and it took us way too long to realise it wasn’t testing people’s coding skills at all and that just getting people to do some pairing was way better.

A chart of the size of the Engineering team at Tyro showing exponential growth from 2013 to 2016I remember… we hired so many people that we doubled the size of the team in 18 months. And then we did it again. And then we did it again.

I remember… that I was just coping to remember all the new people’s names, then I went on holiday for a week, missed four new starters, and never recovered.

I remember… when the Engineering team eventually grew so big that we reluctantly moved Ops to a different floor of the building, and communication between the two groups plummeted.

I remember… pairing with Ops on mystery catastrophe nights, all scratching our heads, ordering pizza when we realised it was way past dinner time, and that “Aha!” feeling when someone found an entry in a log or ran a query on a table that had seemed totally unrelated to the symptoms but showed something that no one expected could ever happen.

I remember… organising our first innovation sprint – ‘CodeBlitz’ – and being surprised by the different mood in the room as people were intensely focused on getting their own innovative idea hacked together within two days so they could demo it.

I remember… when we decided it would be a good idea to build our next link to another bank as its own piece of software rather than adding it to an existing monolith – one of our first steps toward a microservices architecture (before that word existed). We recently celebrated having over 100 services deployed in Production.

The Journey to the Bank

Four people in suits walking in front of a building with tall, thick columns, possibly a bank or museum, with long shadows in the early morning light.I remember… that time my boss came to me and asked if my team could start on building a bank the next week.

I remember… when we took a completely agile approach to building a bank…

“Where do we start?”
“Well, what’s the most important thing a bank does?”
“Keeps people’s money in an account.”
“Okay, let’s write a piece of software that keeps money in an account instead of sending it to another bank.”
And so we wrote that and got it working before we did anything else.

I remember… when the regulator announced they were retiring our limited EFTPOS banking license, and we were told the banking side-project was now the rush to a full banking license mission, the #1 priority of the company, and that we had 18 months to deliver.

I remember… when we were 12 months into building our core banking system, just weeks away from delivering it exactly when we had estimated… and someone uncovered 3 more months of mandatory work.

I remember… when we received the results of an external security audit of our in-progress core banking system and the synopsis was “You guys are pretty up there with your security, but here’s 15 other major things you should think about improving.”

I remember… the frankly unbelievable news that we’d been granted a full banking license by APRA. It felt like a war was over.

I remember… when we’d just finished turning on the core banking system and we were told, “Well done. Now you’ve got 12 months to build a lending product from scratch, ship it, and get customers onto it.” We did it in 6.

Time Keeps on Slipping

Public binoculars with a small lake just beyond and a foggy, blurred landscape in the background.I remember… feeling like my contribution to the company was having less and less impact due to the growth and organisational changes, and starting to seriously think about moving on to somewhere else. Eventually, I realised that I didn’t have to be bound by my historical contribution to Engineering, and that Product Management might be a place where I could probably develop a new expertise and have a large impact on the company’s future.

I remember… getting up the courage to ask the co-founder and Head of Product about moving into a Product Management role, expecting to get a grilling about what product was and what skills I had that I thought would be relevant. Instead his response was just, “Yeah, that makes sense. When would you like to move?”

I asked my wife what she remembers, and she said she remembers when she would show up to the Christmas party and know everyone’s name, but nowadays I sometimes tell her I’m going to someone’s leaving drinks and she says she’s never heard of them.

I remember… starting to reflect on what I’d been part of in 10 years at Tyro and realising there was almost nothing that I’d achieved by myself; everything significant I’d been involved in had been a team effort – sometimes a team of two, sometimes over a hundred, but almost always a team. That’s how we roll.

Image credits:
Kids, older photo‘ by Joe Crawford
Start of the Steep Trail‘ by Dan Cook
Sydney Harbour Bridge‘ by gramarye
Power ups‘ by Kirt Edblom
Bankers‘ by Chris Brown
Eye of the Beholder‘ by hjl (flickr)

Book Recommendations from Sydney Technology Leaders

Last week I went to the Sydney Technology Leaders’ Meetup, which we hosted in the Tyro Fintech Hub. There was a trio of great talks, and a panel discussion with the speakers at the end.

When asked what they do to help train new leaders, one of the speakers mentioned “throwing a bunch of books at them”. So I took the opportunity to ask the speakers, if they could only recommend one or two books to a new leader, what would each of them recommend. Continue reading

Design Kata: Learn software architecture while having fun

Children practising a karate kata. This article describes design kata, where software developers practise designing software architecture.At Tyro, we don’t have anyone with the title of Architect, Designer or Tech Lead who designs software and then asks other people to build it. Instead, each team of Software Engineers does architecture and design as part of their iteration planning sessions for the stories we’re taking on.

As a Team Lead, the two main goals I keep in mind for each person are: keep them happy and keep them growing. One of the ways I try to ensure this happens is by meeting with each person regularly so we can chat about how to make sure these things are true or at least heading in the right direction.

A topic that’s come up with a few people lately is software design and architecture. Specifically, I’ve had a couple of comments along the lines of: “When we’re designing things, I want to contribute more, but I’m not really sure where to start.” Continue reading

Notes from YOW! 2014: Mary Poppendieck on ‘The (Agile) Scaling Dilemma’

I attended YOW! Sydney 2014 and thought some people might get something useful out of my notes. These aren’t my complete reinterpretations of every slide, but just things I jotted down that I thought were interesting enough to remember or look into further.

Lots of empty seats at a stadium. Can Agile scale to this kind of crowd?Mary Poppendieck (@mpoppendieck) spoke about scaling agile teams. (Slides)

She started by saying:

“There’s a big assumption that if agile is good, scaling agile must be good.”

Which made my jaw drop. I make that assumption. It had never occurred to me. Maybe agile techniques don’t work in a larger organisation?

She talked about four constraints on scaling: system complexity, organisational mindset, multi-team communication, and the time and energy of bright creative people. Continue reading

10 Reasons You Shouldn’t Have Senior Developers, Tech Leads or Architects

Two weeks ago I published a post titled ‘Why Smart Software Teams Don’t Need Senior Developers, Tech Leads or Architects‘. I received a lot of good feedback, but I also know it was a long read. So, if you’re interested by the title but are looking for a quick brain dump rather than an enjoyable read, here’s the abridged version:

At Tyro Payments, we’ve doubled our Engineering team over the last year.

We don’t hire for, or use, titles like Graduate Developer, Junior Developer, Senior Developer, Tech Lead or Architect. Everyone has the title ‘Software Engineer’.

This is an important part of Tyro’s Engineering team culture. Here are the reasons… Continue reading

Why Smart Software Teams Don’t Need Senior Developers, Tech Leads or Architects

Queue for Steve Jobs' keynote at WWDC 2010

A queue of software developers, not unlike the one that has inundated my inbox for the last year.

We’ve almost doubled our Engineering team at Tyro Payments over the last financial year and we’ll be adding that many again this year.

Most people who’ve worked in or with software teams would imagine that within this surge of hiring we’ve been filling all kinds of different roles – Graduate Developers, Junior Developers, Seniors, a couple of Tech Leads, maybe an Architect. But the truth is we’ve only been hiring for one role: Software Engineer. In fact, it’s the only development role on our team, and it’s the title we give to everyone on the tools, whether they have 20 years’ experience or none. This isn’t just some convenience we came up with to save ourselves HR work. It’s an incredibly important part of the culture at Tyro. Why? Continue reading