Continuous Delivery

The ability to deliver the latest changes to production on demand.

Continuous Deployment

Delivering the latest changes to production as they occur.

Continuous Integration

A development process where each developer integrates tested, changes to trunk very frequently or at least once per day. Trunk is kept ready to deploy at all times.

Continuous integration requires that every time somebody commits any change, the entire application is built and a comprehensive set of automated tests is run against it. Crucially, if the build or test process fails, the development team stops whatever they are doing and fixes the problem immediately. The goal of continuous integration is that the software is in a working state all the time.

Continuous integration is a practice, not a tool. It requires a degree of commitment and discipline from your development team. You need everyone to check in small incremental changes frequently to mainline and agree that the highest priority task on the project is to fix any change that breaks the application. If people don’t adopt the discipline necessary for it to work, your attempts at continuous integration will not lead to the improvement in quality that you hope for.

Excerpt From: Jez Humble & David Farley. “Continuous Delivery: Reliable Software Releases through Build, Test, and Deployment Automation.”

Dependency (Hard)

A hard dependency is something that must be in place before a feature is delivered. In most cases, a hard dependency can be converted to a soft dependency with feature flags.

Dependency (Soft)

A soft dependency is something that must be in place before a feature can be fully functional, but does not block the delivery of code.

Story Points

A measure of the relative complexity of delivering a story. Historically, 1 story point was 1 “ideal day”. An ideal day is a day where there are no distractions, the code is flowing, and we aren’t waiting on anything. No such day actually exists. ;)

Story points should only be used for planned work. Unplanned work or spikes should not be story pointed after the fact. Doing so artificially inflates the average capacity of the team and results in teams over-committing to delivery.


The repetitive, predictable, constant stream of tasks related to maintaining an application.

SRE Workbook: Eliminating Toil

Unplanned Work

Any work that the team inserts before the current planned work. Critical defects and “walk up” requests are unplanned work. It’s important that the team track all unplanned work and the reason so that steps can be taken by the team to reduce the future impact.

Vertical Sliced Story

A story should represent a response to a request that can be deployed independently of other stories. It should be aligned across the tech stack so that no other story needs to be deployed in concert to make the function work.


  • Submitting a search term and returning results.
  • Requesting user information from a service and receiving a response.


Work in progress is any work that has been started but not delivered to the end-user

Last modified December 15, 2022: Fixing some typos (#28) (9efde39)