# Sequenzy (/docs/v/0.6.1/adapters/sequenzy)



The Sequenzy adapter calls Sequenzy's transactional send endpoint over `fetch` — no extra dependency. Its distinctive feature: reserved `metadata` keys switch a send from direct content to a Sequenzy template slug, so the same message shape covers both modes.

<ProviderBadge adapter="sequenzy" />

## Configure [#configure]

Create a Sequenzy API key and verify the sender domain or address you plan to use in `from`.

```ts title="lib/email.ts"
import { createEmailClient } from "@opencoredev/email-sdk";
import { sequenzy } from "@opencoredev/email-sdk/sequenzy";

export const email = createEmailClient({
  adapters: [sequenzy({ apiKey: process.env.SEQUENZY_API_KEY! })],
});
```

<TypeTable
  type="{
  apiKey: {
    description: &#x22;Sequenzy API key.&#x22;,
    type: &#x22;string&#x22;,
    required: true,
  },
  baseUrl: {
    description: &#x22;Override the API origin, e.g. for a proxy.&#x22;,
    type: &#x22;string&#x22;,
    default: '&#x22;https://api.sequenzy.com/api/v1&#x22;',
  },
  fetch: {
    description: &#x22;Custom fetch implementation for tests or special runtimes.&#x22;,
    type: &#x22;typeof fetch&#x22;,
  },
}"
/>

## Send [#send]

Sequenzy accepts up to 50 recipients and one `replyTo` per message. Flat `metadata` values become Sequenzy `variables`. Sequenzy has a single `body` field, so when a message carries both `html` and `text`, the adapter sends `html` — omit `html` to send plain text.

```ts
const result = await email.send({
  from: "Acme <hello@acme.com>",
  to: [{ email: "user@example.com", name: "Ada" }],
  replyTo: "support@acme.com",
  subject: "You've been invited to Acme",
  html: "<p>Ada invited you to the Acme workspace.</p>",
  metadata: { inviterName: "Ada", workspaceName: "Acme" },
});

console.log(result.id); // Sequenzy jobId; result.accepted lists the recipients Sequenzy took
```

Attachments work two ways: an `http(s)` `path` is forwarded as a Sequenzy URL attachment; anything else is encoded as base64 `content`.

Reserved metadata keys map to provider fields instead of `variables`:

| Metadata key                                             | Sequenzy field         |
| -------------------------------------------------------- | ---------------------- |
| `sequenzySlug`                                           | `slug`                 |
| `sequenzyPreview`                                        | `preview`              |
| `subscriberExternalId` or `sequenzySubscriberExternalId` | `subscriberExternalId` |

When `metadata.sequenzySlug` is set, the adapter sends a template request: the slug and variables drive rendering, and `subject`/`html`/`text` are left out of the payload (they still satisfy local message validation).

```ts
await email.send({
  from: "Acme <hello@acme.com>",
  to: "user@example.com",
  subject: "You've been invited to Acme",
  html: "<p>Fallback body for local validation.</p>",
  metadata: { sequenzySlug: "workspace-invite", inviterName: "Ada" },
});
```

<Callout type="warn" title="No cc, bcc, headers, or tags">
  Sequenzy rejects `cc`, `bcc`, `headers`, and `tags` with an `EmailValidationError` before any
  request — as it does for more than 50 recipients or more than one `replyTo`. Check
  [field support](/docs/v/0.6.1/adapters/field-support) before using Sequenzy in a fallback route.
</Callout>

## Verify from the CLI [#verify-from-the-cli]

```bash
SEQUENZY_API_KEY="seq_live_..." npx email-sdk doctor --adapter sequenzy
```

```bash
SEQUENZY_API_KEY="seq_live_..." npx email-sdk send \
  --adapter sequenzy \
  --from "Acme <hello@acme.com>" \
  --to user@example.com \
  --subject "Sequenzy smoke test" \
  --text "It works" \
  --dry-run
```

Drop `--dry-run` for one real smoke send — the only check that proves the API key and sender verification are ready.