Kind
Hosted service with an API; nothing resident on the server
Interface
SSH into each server; webhooks from GitHub, GitLab, Bitbucket
Runs on
Ubuntu or FreeBSD servers with scp; often Forge-provisioned
Installed by
envoyer.io: add the project, its servers and an SSH key
Voice
none. Deploys start from the dashboard, a push, or the API
Scales by
A project deploys to one or more servers at the same time
Range
Cloud: no. Cloud deploys from git itself; no server of yours
Forge, VPS: yes. Envoyer imports Forge servers; one-server deploys now native
Vapor: no. A Vapor deploy is a Lambda release, not a symlink