All features
Developer
Environments & API keys
Each environment is a self-contained workspace with its own API key, integrations, templates, rules and message history. Switch between them in the UI and keep test traffic completely separate from production.
app.messy.sh/environments
API key per environment
Server-to-server auth scoped to one workspace.
Scoped everything
Integrations and rules resolve per environment, then account.
Subject tagging
Prefix non-prod email subjects so they're unmistakable.