# Email flow: automation that starts on an event

An email flow is automation that starts when something happens, like a signup or a purchase, and runs steps for that person. How it works in Mimeo.

**Definition:** An email flow is automation that starts when something happens, such as a signup, a purchase or a stretch of silence, and then runs a set of steps for that person: send, wait, branch on what they did, tag.

## How it works

A flow has a **trigger** and **steps**. The trigger is something that happens to one person. The steps are what to do about it, in order, for that person alone. A post-purchase flow might read:

1. Trigger: `purchase`.
2. Send the thank-you email.
3. Wait 14 days.
4. If they bought again, stop here.
5. Otherwise, send the cross-sell.

Waits, branches and stops are what separate a flow from a fixed series of emails. A flow can also wait for something: a checkout reminder waits for the purchase, and branches when the wait runs out.

## Why it matters

- **Timing.** An email sent because of what someone just did lands while it matters to them.
- **Relevance.** Branches mean a customer and a browser get different follow-ups from the same trigger.
- **It runs on its own.** Once it's live, every purchase, signup or cancellation gets handled the same way.
- **Mistakes repeat too.** A wrong branch hits everyone who passes through, so testing before going live matters.

## How Mimeo handles it

A Mimeo [flow](https://mimeohq.com/docs/usage/flows) starts on any event Mimeo receives: from your site, app or store through the [event API](https://mimeohq.com/docs/api/events), or from Mimeo itself, such as `tag_added`, `field_changed` and `sequence_completed`. Flows can also start on an approaching subscription renewal or end, or on a stretch of inactivity. Steps send an email, start a sequence, add or remove a tag, set a field, wait, wait at a gate, branch, fire an event, exit or prune.

Each flow is one validated JSON definition. You edit it in the diagram, or your agent edits it through the API or MCP. A [dry run](https://mimeohq.com/docs/usage/flows#dry-run) walks a real person through the flow with their real data and sends nothing. Activating checks the definition first, every activation is saved as a version you can roll back to, and pausing holds the emails already queued. See [Mimeo terms](https://mimeohq.com/docs/glossary#working-in-mimeo) for flows, triggers and runs in Mimeo's own words.

## Sources

1. [Flows](https://mimeohq.com/docs/usage/flows), checked 2026-11-10
2. [The event contract](https://mimeohq.com/docs/api/events), checked 2026-11-09

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This is the Markdown copy of https://mimeohq.com/glossary/email-flow.