Insights for great software & great teams

How-to guides, tooling tips and real-world advice for developers and product managers tired of broken software. Let’s fix this mess together.

Sign up and get insights delivered to your inbox.

How-to guides, tooling tips and real-world advice for developers and product managers tired of broken software. Let’s fix this mess together.

Want to talk shop or tackle a problem in real time? Unpack it with a developer or product manager.

Get our newsletter

Tradeoffs chart for changeability, cost, and reliability

What is legacy software in the age of AI?

Software becomes legacy by succeeding long enough to accumulate the weight of every decision and shortcut made along the way. Users feel it as friction. Engineers feel their momentum slip. The business watches costs climb. AI changes two of those. The third may be getting worse.

Todd Kaufman

Legacy modernization

Three people emerge from darkness toward light and a neon green path

In the age of AI we’re in this together

River Lynn Bailey

River Lynn Bailey

Cognitive hazard study diagram showing a laptop, coffee mug, and documentation sinking into a tarpit

Organizational observability: The AI alignment problem starts upstream

Dave Mosher

$Puzzled math meme with a rubber duck wearing a fedora and trench coat$

The shockingly simple math for why we need test automation

Gabriel Côté-Carrier

Gabriel Côté-Carrier

Double Takes

+ Expand posts

- Collapse POSTS

Double Takes

TDDing with Claude is like having a pair that removes all the failing assertions every time you go to the bathroom.

Steve Jackson

State machines are the answer for those seeking determinism in the era of AI agents.

Dave Mosher

A Slack conversation left Doc reflecting on what bug bashes say about the systems we work in.

Doc Norton

Test-driven development is to programming what double-entry bookkeeping is to accounting.

Neal Lindsay

The fundamental character flaw of the software creator is not the misguided belief that they can solve any problem with software. Instead, it is the belief they can understand how their own software works before they create it.

Steve Jackson

We may need a SaaS appendix for Zawinski's law:

Any SaaS platform attempts to expand until it is a social network.

Matt Jones

Using CockroachDB with Rails

Discover how to set up CockroachDB with your Rails app. Follow our step-by-step guide for seamless integration and enhanced scalability.

Ali Ibrahim

Accelerate quality software

ruby

rails

React Context for dependency injection not state management

Learn how to use React Context for dependency injection instead of state management, with insights from Redux maintainer Mark Erikson.

Tommy Groshong

Software tooling & tips

api

react

javascript

Double Agent Profile: Landon Gray

Landon Gray

No items found.

Rough, uncut gems

How to implement your own Twitter OAuth login flow

Dive into the nuances of dependency management with a practical example of implementing OAuth sign-in for a Ruby on Rails app. Discover the trade-offs and make informed decisions.

Justin Searls

Accelerate quality software

ruby

rails

security

The best interview process ever for senior software engineers

Nichol Alexander shares an outside perspective on Test Double’s uniquely fair and welcoming interview process for senior software engineers.

Nichol Alexander

Nichol Alexander

Recruiting & careers

No items found.

How to completely uninstall and reinstall Homebrew Postgres

Is Postgres erroring with "could not read block 39" or "bad address"? If you installed Postgres via Homebrew on a Mac, here's the quickest way to wipe the slate clean with a fresh install

Justin Searls

Software tooling & tips

postgres

Author photo and post title

Adding disallowed deprecations to Rails 6.1

Discover how the Disallowed Deprecations feature in Rails 6.1 helps you maintain your app efficiently. Say goodbye to pesky deprecation warnings for good!

Cliff Pruitt

rails

ruby

testing

Author photos

How effective pull request reviews transform your team

Steve Jackson

Communication & teams

teams

communication

professional-growth

You're N.E.A.T.!

Technology is a means to an end: answers to very human questions. We want to connect with other folks who share that belief.

Ways to connect

Test Double Executive Leadership Team

Learn about our team

Like what we have to say about building great software and great teams?