Choosing a sending feature
Pick between a single send, a batch, a scheduled send, a template, and a marketing send, and see which ones combine.
Everything goes through POST /v1/emails (or /batch). Scheduling, templates, attachments and marketing are fields on that request, and they combine.
Decision table
| Feature | What it is | Use it when | Field or endpoint | Guide |
|---|---|---|---|---|
| Single send | One message, one call | You're sending one message right now | POST /v1/emails | How sending works |
| Batch | Many messages in one request | You have a list to send in one pass | POST /v1/emails/batch | Batch sending |
| Scheduled send | A send that dispatches later | The message shouldn't go out yet | scheduled_at | Scheduled sends |
| Template | Server-rendered content from a stored template | The body is templated rather than composed per call | template | Templates |
| Attachments | Files carried with the message | The message needs to carry a file, or embed an inline image | attachments | Attachments |
| Marketing | A commercial send with its own compliance gates | The message is a newsletter, promo, or other commercial mail | type: "marketing" | Marketing emails and unsubscribe |
They combine
A scheduled batch of template renders carrying a PDF is those four fields set together.
A marketing send accepts exactly one recipient across to, cc, and bcc. The limit applies per message, so a batch may carry marketing messages, each addressed to one recipient. See Send an email for the type field's full schema.
Batch or a loop
A batch is checked and accepted as one all-or-nothing unit. A loop of single sends gives you per-message error isolation and per-message idempotency keys, at the cost of N requests. See Batch or loop?.
Transactional or marketing
The type field takes transactional or marketing and defaults to transactional when omitted. Pick the value that matches the message's main purpose. See Email categories for where the line falls, and Marketing emails and unsubscribe for what a marketing send requires.