Question: Assuming that feature flag toggles are a good idea, and should be implemented into code that developers write. For example Etsy swear by them as a [major part of their culture](https://codeascraft.com/2011/02/04/how-does-etsy-manage-development-and-operations/).

**What is a good way to persuade (and enforce) developers to start using feature flag toggles?**

More information about feature flag toggles is explained in [Q: How to use feature flag toggles](https://devops.stackexchange.com/questions/162/how-to-use-feature-flag-toggles), [Q: What are feature flag toggles](https://devops.stackexchange.com/questions/344/what-is-a-feature-flag-toggle-and-when-to-use-them-or-not) and very extensively in Pete Hodgson's [article on the subject on Martin Fowler's blog](https://martinfowler.com/articles/feature-toggles.html).

Answer: 
Feature toggles are a common practice in high-velocity development because they de-couple *development* from *release.* Dev teams can "soft-release" a new feature to production, in a disabled state. This allows the feature to be released any time. If the feature is dependent on other work or preparation, it doesn't have to wait for a major release to go to production.

As far as "convincing" developers to use them, that's an exercise in making the case for the freedom it offers. My experience is that it's not a tough sell to developers. It's management that tends to be reluctant to try new things. Try this:

* Find a feature toggle framework. Management/the business may be more
amenable to trying something supported by a common system
* Start small. Introduce the toggle system on a trial basis for a feature that will demonstrate its utility.
* Demonstrate the toggle's ability to do A/B testing. Enable the toggle for a subset of your web farm, then gather metrics on behavior. Tiny differences in page layout have been demonstrated to have huge effects on revenue for retail applications (e.g. Ebay, Amazon)
Developers (and usually development managers) usually look for two outcomes associated with framework: ease of management, and speed of deployment. You want to ship code faster, and easier.

Provide evidence that the approach works; try building a small POC using feature flags versus the old way. Case studies matter less to tactical people (developers\engineers) than strategic people (middle management\product designers).