Send a batch of emails
Up to 100 DISTINCT emails in one call — each with its own recipient, template and props. One round-trip instead of 100.
This is not a bulk-campaign endpoint: every entry is still a single-recipient message and goes through the same idempotency, suppression, cap and sender checks a single send does. Nothing is skipped for speed.
Entries succeed and fail independently. The response is always 202 with a per-index result array in request order — data[i] corresponds to emails[i]. A success carries id and status; a failure carries an error object with the same codes a single send returns. Check the array, not the status code.
Idempotency: give each entry its own idempotency_key, or pass an Idempotency-Key header and each entry derives <header>:<index>. Retrying a partially-succeeded batch then replays the successes and retries only the failures.
Requires a write-scope key.
bearerAuth writeAuthorizationBearer <token>An API key from the dashboard under Settings → API keys, sent as Authorization: Bearer aem_….
Authorization has two independent axes.
The scope is ranked — a key satisfies any requirement at or below its own tier:
read— see messages, contacts and metrics. Changes nothing, and cannot send.write— everythingreaddoes, plus managing templates, contacts, automations, segments and suppressions. This is what editing a template needs.admin— everythingwritedoes, plus sending configuration: domains, senders, webhook registration, kill switch, daily cap, brand.
There is no approve scope. It was a rung once; it is not one now, and a key requested with it is rejected.
The approval grant (can_approve) is a separate boolean, not a rung. Delivering mail to a real inbox needs write and the grant. Keeping them on separate axes is what makes the review gate a control rather than a convention: a key that may propose is not automatically a key that may approve its own proposal.
Give your application the lowest tier that works. Most need write and the grant — the dashboard mints that combination as Send + manage; Manage only is the same rung with the grant withheld.
Scope: write
Idempotency-Key?stringNamespaces the batch. Each entry derives <key>:<index> unless it sets its own idempotency_key.
length <= 256application/json- body
emails*array<>Up to 100 distinct messages, each with its own recipient and template. Results come back in this order.
1 <= items <= 100Accepted. Every entry has a result; read data for per-entry outcomes.
application/json- response
data?array<>Same order as the request.
queued?integerfailed?integercurl -X POST 'https://sendandretain.com/api/v1/emails/batch' \ -H 'Idempotency-Key: order-confirmations-2026-08-10' \ -H 'Content-Type: application/json' \ -d '{ "emails": [ { "to": "[email protected]", "template": "receipt", "props": { "total": "£42.00" } }, { "to": "[email protected]", "template": "welcome", "props": { "firstName": "Sam" } } ]}'{ "data": [ { "index": 0, "id": "msg_3aF9c1", "status": "queued" }, { "index": 1, "error": { "code": "template_not_found", "message": "No template 'welcom'." } } ], "queued": 1, "failed": 1}