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Building Better Software Faster with Shared Principles

Betterment’s playbook for extending the golden hour of startup innovation at scale.

Articles by John Mileham

By John Mileham
Director of Architecture, Betterment  |  Published: January 31, 2018

Betterment’s promise to customers rests on our ability to execute. To fulfill that promise, we need to deliver the best product and tools available and then improve them indefinitely, which, when you think about it, sounds incredibly ambitious or even foolhardy.

For a problem space as large as ours, we can’t fulfill that promise with a single two pizza team. But a scaled engineering org presents other challenges that could just as easily put the goal out of reach. Centralizing architectural decision-making would kill ownership and autonomy, and ensure your best people leave or never join in the first place. On the other hand, shared-nothing teams can lead to information silos, wheel-reinventing, and integration nightmares when an initiative is too big for a squad to deliver alone.

To meet those challenges, we believe it’s essential to share more than languages, libraries, and context-free best practices. We can collectively build and share a body of interrelated principles driven by insights that our industry as a whole hasn’t yet realized or is just beginning to understand. Those principles can form chains of reasoning that allow us to run fearlessly, in parallel, and arrive at coherent solutions better than the sum of their parts.

I gave a talk about Betterment’s engineering principles at a Rails at Scale meetup earlier last year and promised to share them after our diligent legal team finished reviewing. (Legal helpfully reviewed these principles months ago, but then I had my first child, and, as you can imagine, priorities shifted.)

Without any further ado, here are Betterment’s Engineering Principles. You can also watch my Rails at Scale talk to learn why we developed them and how we maintain them.

Parting Thoughts on Our Principles

Our principles aren’t permanent as-written. Our principles are a living document in an actual git repository that we’ll continue to add to and revise as we learn and grow.

Our principles derive from and are matched to Betterment’s collective experience and context. We don’t expect these principles to appeal to everybody. But we do believe strongly that there’s more to agree about than our industry has been able to establish so far. Consider these principles, along with our current and future open source work, part of our contribution to that conversation.

What are the principles that your team share?

This article is part of Engineering at Betterment.

These articles are maintained by Betterment Holdings Inc. and they are not associated with Betterment, LLC or MTG, LLC. The content on this article is for informational and educational purposes only. © 2017–2019 Betterment Holdings Inc.

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