Core concepts
The handful of ideas the rest of the docs build on.
A quick tour of the pieces you'll work with. Each links to a deeper page.
Project
A project is one company. It owns its own domains, senders, templates, contacts, suppression list, automations, and API keys. Everything is scoped to a project — an API key can only touch its own project's data.
Template
An email you can send, authored with your company's brand. Published template versions are immutable — editing creates a new draft; you publish it to make it sendable. See Templates.
Contact
A person you send to, identified by email (and optionally your own
external_id). Contacts carry custom attributes you can reference in
templates and filter on in automations. See
Contacts & events.
Event
Something a contact did (order.completed, trial.started). You emit events
via the API; active automations whose filter matches enroll the contact. See
Contacts & events.
Automation
An event-triggered sequence of steps (delays, sends) with optional A/B variants. Automations are always created paused — enabling one is a deliberate decision. See Automations.
Suppression
The list of addresses you must not send to — bounces, complaints, unsubscribes, and manual blocks. The send path checks it on every message. See Suppression & unsubscribe.
Provider
The delivery backend (Resend or SendGrid) behind your project. You connect one per project; Send & Retain owns everything above it. See Providers.