What is the meaning of Zero Downtime Development?

That means if you push something to your Server Envoyer checks if there are some errors and if ne site would go down after your changes.

If so Envoyer will notify you about the Issue.

That was my understanding of this Zero Downtime Dev.

Usualy when you deploy without any strategy it implies downtime (restarting the server, updating composer packages, running migrations, etc...). Zero downtime means your website stays online during the whole process.

Basically it just means that you have multiple folders which are switched when ready to be deployed.

Basic steps are;

1. Symlink to current build is set from previous deploy
2. Clone/build/download dependencies into a new release folder
3. Switch symlink to new folder

@ericahernandez573 A site that doesn’t go down while you deploy.

As @bashy says, this is achieved by deploying a second version of your website. When every thing is all good, a switch is made to serve requests from the new codebase rather than the old one, meaning there’s no periods of being offline during the deployment process.