> For the complete documentation index, see [llms.txt](https://docs.mailofly.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.mailofly.com/rest-api/compose.md).

# Compose (one-off send)

Send transactional or ad-hoc email without a campaign. Authenticate with `Authorization: Bearer` (API keys). Use **account\_key** (`acc_…` from Accounts, not the account UUID). Up to 100 recipients per request; daily limits still apply.

## POST `/api/v1/compose`

**Compose (one-off send)**

Send up to 100 recipients without a campaign. Required: account\_key (public acc\_… string, not the account UUID). Content: either template\_id (saved template UUID) or both subject and body — never both. Recipients: manual To list or recipients.type "contacts" with contact\_ids (contact UUIDs from /api/v1/contacts, not template ids). variables fills {{ placeholders }}; omitted required tags return 400 with missing\_variables. Cc/Bcc are not supported on this endpoint (To only).

### Request body — Example — inline subject & body, manual To

Use template\_id instead of subject/body to load a saved template. For contacts, set recipients.type to "contacts" and pass contact\_ids.

```json
{
  "account_key": "acc_YOUR_ACCOUNT_KEY",
  "subject": "Hi {{first_name}}",
  "body": "<p>Code: <strong>{{promo_code}}</strong></p>",
  "recipients": { "emails": ["friend@example.com"] },
  "variables": { "first_name": "Alex", "promo_code": "SAVE20" }
}
```

### Response fields

* **ok** (`boolean`) — True when the request was accepted and sends were attempted.
* **sent** (`number`) — Count of messages queued or sent successfully.
* **failed** (`{ email: string; error: string }[]`) — Per-recipient failures (empty when all succeeded).

### Examples

#### 200 — OK

```json
{ "ok": true, "sent": 1, "failed": [] }
```

#### 400 — Validation

```json
{ "error": "…", "missing_variables": ["promo_code"] }
```

#### 404 — Unknown account

```json
{ "error": "…" }
```

### cURL

```bash
curl -sS -X POST "https://www.mailofly.com/api/v1/compose" \
  -H "Accept: application/json" \
  -H "Authorization: Bearer mf_live_your_key_here" \
  -H "Content-Type: application/json" \
  -d '{"account_key":"acc_…","subject":"Hi {{first_name}}","body":"<p>{{promo_code}}</p>","recipients":{"emails":["friend@example.com"]},"variables":{"first_name":"Alex","promo_code":"SAVE20"}}'
```

## Related

* [Product guide: Compose](/product-guides/compose.md)
* [Templates API](/rest-api/templates.md)
* [Accounts API](/rest-api/accounts.md)
* [← API overview](/rest-api/api.md)


---

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