---
title: Email
icon: mail
description: Set up, configure, and run the Reloop platform email microservice locally.
---
> For the complete documentation index, see [llms-docs.txt](/llms-docs.txt) or the site index [llms.txt](/llms.txt). Full docs corpus: [llms-full-docs.txt](/llms-full-docs.txt). Prefer markdown URLs (append `.md`) for agent consumption. Product skill: [skill.md](/skill.md).


Platform transactional emails triggered by NATS events (invites, OTPs, billing alerts).

<Tip>
Run [`bun setup`](/docs/setup) once from the monorepo root. Env files come from `bun setup` / `bun env:setup`.
</Tip>

<Warning>
**Email** ≠ **Mail**. Email sends platform notifications to Reloop users (invites, password resets). [Mail](/docs/setup/backend/mail) is the customer-facing send API for their audiences.
</Warning>


## Overview

| Property | Value |
| :--- | :--- |
| **Directory** | `apps/backend/email` |
| **Port** | `8022` |
| **Local URL** | [https://local.reloop.sh/api/email](https://local.reloop.sh/api/email) |
| **Swagger UI** | [https://local.reloop.sh/api/email/openapi](https://local.reloop.sh/api/email/openapi) |
| **Stack** | ElysiaJS · Redis · NATS |


## Quick start

```bash
bun be:email:dev
```

Or `bun backend:dev` / `bun dev`. Locally, when `RELOOP_API_KEY` is unset, mail falls back to Mailpit SMTP (`localhost:1025`).


## Environment

`apps/backend/email/.env` — from `bun setup` / `bun env:setup`.

```bash
EMAIL_PORT=8022
PORT=8022
BASE_URL="https://local.reloop.sh"
NATS_URL=nats://localhost:4222
RELOOP_API_KEY=
RELOOP_SENDER_DOMAIN=
ONBOARDING_TEST_DOMAIN=
NODE_ENV=development
```

| Variable | Required | Default | Notes |
| :--- | :--- | :--- | :--- |
| `EMAIL_PORT` / `PORT` | **YES** | `8022` | Listening port |
| `BASE_URL` | **YES** | `https://local.reloop.sh` | Platform base URL |
| `NATS_URL` | **YES** | `nats://localhost:4222` | Event subscriptions |
| `RELOOP_API_KEY` | Prod | — | API key for the org that owns the sender domain(s); used by `reloop-email` |
| `RELOOP_SENDER_DOMAIN` | Prod | — | System product mail From domain (auth, billing, invites) |
| `ONBOARDING_TEST_DOMAIN` | Prod | — | Onboarding “Send email” From domain only (can differ) |


## Commands

| Command | Description |
| :--- | :--- |
| `bun be:email:dev` | Start dev server with hot reloading |
| `bun run --filter=be-email build` | Compile production bundle |
| `bun run --filter=be-email start` | Run compiled production build |
| `bun run --filter=be-email check-types` | TypeScript type-check |


## Architecture

| Layer | Detail |
| :--- | :--- |
| **Triggers** | Subscribes to NATS subjects (`auth.*`, `billing.*`, etc.) |
| **Delivery** | Sends via the [mail](/docs/setup/backend/mail) pipeline using `RELOOP_API_KEY` when set |
| **Schema** | `email_log` in `packages/db/src/schema/email.ts` |


## Next

<CardGroup cols={2}>
  <Card icon="rocket" title="Setup" href="/setup">
    One-command local bootstrap
  </Card>
  <Card icon="mail-single" title="Mail" href="/setup/backend/mail">
    Customer send API (different service)
  </Card>
  <Card icon="lock" title="Auth" href="/setup/backend/auth">
    Triggers invites and OTP emails
  </Card>
  <Card icon="globe" title="Port reference" href="/setup/port">
    Gateway routes and ports
  </Card>
</CardGroup>