Editor's note: If you like CLIs, you should check out oclifconf taking place on Friday, May 31st in San Francisco. It’s the first community get-together for oclif! Space is limited so let us know soon if you are interested in joining.

What is it that makes working from the command line so empowering? It can feel archaic at times, sure, but when you remember the right sequence of words, characters, and symbols for what you’re trying to do, it hits you with a sense of accomplishment and mastery over your tools that no graphical interface can compete with.

So what better way to continue your adventures as a developer than by developing your own CLI tool?

In this post, we’ll go over what...

If you're like me, or like many other Python developers, you've probably lived (and maybe migrated) through a few version releases. Python 3.7(.3), one of the latest releases, includes some impressive new language features that help to keep Python one of the easiest, and most powerful languages out there. If you're already using a Python 3.x version, you should consider upgrading to Python 3.7. Read on to learn more about some of the exciting features and improvements.

Data Classes

One of the most tedious parts about working with Python prior to 3.7 in an object-oriented way was creating classes to represent data in your application.

Prior to Python 3.7, you would have to...

Setting up a database is a relatively straightforward process (Heroku has an add-on for that), but getting it to run well in production is sometimes another matter. As your application grows and your data grows along with it, you will likely find a number of performance bottlenecks specifically related to your database, and this post aims to help you diagnose and address those issues when they arise.

As with all components of your infrastructure it’s important to have early visibility into the performance characteristics of your database. Watching this data as your application grows will give you a much better chance of spotting performance issues and regressions as they’re introduced.


Heroku has many public API endpoints. Each of these endpoints needs to be tested so that we know how they work, and documented so that our customers (and other API consumers) know how they work. Follow along, and we’ll learn how Heroku uses JSON Schema to test and document our Platform API – and how it helped us uncover an unexpected bug, rooted in the way the Oj gem parses Big Decimals.


JSON Schema files are like blueprints that define the structure and semantics of other JSON documents. When a JSON Schema file is applied to a JSON document, you can determine whether the document is valid (conforms to the schema) or is invalid (does not conform to the schema).

So how do we at Heroku use...

When we open-sourced buildpacks nearly seven years ago, we knew they would simplify the application deployment process. After a developer runs git push heroku master, a buildpack ensures the application's dependencies and compilation steps are taken care of as part of the deploy.

As previously announced, we've taken the same philosophies that made buildpacks so successful and applied them towards creating Cloud Native Buildpacks (CNB), a standard for turning source code into Docker images without the need for Dockerfiles. In this post, we'll take a look at how CNBs work, how they aim to solve many of the problems with that exist with Dockerfile, and how you can use them with...

Browse the archives for engineering or all blogs Subscribe to the RSS feed for engineering or all blogs.