Email

Send single and bulk emails, and track delivery status by job ID.

All examples assume you've set the API key in the constructor. For multi-tenant usage, pass { apiKey } as the last argument to any method. See Configuration.

Send Single Email

Send one email to one recipient.

const result = await outbound.email.send({
  toEmail: 'user@example.com',
  fromEmail: 'noreply@yourcompany.com',
  emailSubject: 'Your order has shipped',
  htmlBody: '<h1>Order #1234 Shipped</h1><p>Your package is on its way.</p>',
  textBody: 'Order #1234 Shipped. Your package is on its way.',
  senderName: 'YourCompany',
  replyTo: 'support@yourcompany.com',
});

Full Parameters

await outbound.email.send({
  // Required
  toEmail: 'user@example.com',
  fromEmail: 'noreply@yourcompany.com',  // must be a verified domain
  emailSubject: 'Subject line',
  htmlBody: '<h1>Email content</h1>',

  // Optional
  textBody: 'Plain text fallback',
  senderName: 'Display Name',            // shows as "Display Name <noreply@...>"
  replyTo: 'support@yourcompany.com',
  ccEmail: 'cc@example.com',
  bccEmail: 'bcc@example.com',
  priority: 'high',                       // 'critical'|'urgent'|'high'|'normal'|'low'|'deferred'|'backlog' (default: 'normal')
  idempotencyKey: 'order-shipped-1234',   // prevents duplicate sends
  metadata: { orderId: '1234', userId: 'u_abc' },
  headers: { 'X-Custom-Header': 'value' },
  tracking: { opens: true, clicks: true },
  attachments: [
    {
      filename: 'invoice.pdf',
      content: 'base64-encoded-content-here',
      contentType: 'application/pdf',
    },
  ],
});

Parameters Reference

Field	Type	Required	Description
`toEmail`	`string`	Yes	Recipient email address
`fromEmail`	`string`	Yes	Sender email — must be a verified domain assigned to your tenant
`emailSubject`	`string`	Yes	Email subject line
`htmlBody`	`string`	Yes	HTML email body
`textBody`	`string`	No	Plain text alternative (recommended for deliverability)
`senderName`	`string`	No	Display name shown to recipient
`replyTo`	`string`	No	Reply-to email address
`ccEmail`	`string`	No	CC recipient
`bccEmail`	`string`	No	BCC recipient
`priority`	`string`	No	`'critical'`, `'urgent'`, `'high'`, `'normal'` (default), `'low'`, `'deferred'`, or `'backlog'`. Unrecognized values are treated as `'normal'`.
`idempotencyKey`	`string`	No	Unique key to prevent duplicate sends — expires after 24 hours (see below)
`campaignId`	`string`	No	Tag this email as part of a campaign — enables bulk cancellation via `email.cancel()`
`metadata`	`object`	No	Custom key-value pairs stored with the email
`headers`	`object`	No	Custom email headers
`tracking`	`object`	No	Open and click tracking configuration
`attachments`	`Attachment[]`	No	File attachments (max 10MB each, 25MB total)

Response

{
  message: 'Email queued successfully',
  jobId: '550e8400-e29b-41d4-a716-446655440000',
  messageId: '660e8400-e29b-41d4-a716-446655440001'
}

Field	Description
`jobId`	Unique job ID — use this to check delivery status
`messageId`	Unique message ID for this specific recipient

Possible Errors

Error	Status	Cause
`BadRequestError`	400	Missing required fields, invalid email format
`AuthenticationError`	401	Invalid or missing API key
`ForbiddenError`	403	Domain not verified, tenant suspended
`ConflictError`	409	Idempotency key is currently being processed by another request
`RateLimitError`	429	Per-second rate limit exceeded, or the global AWS SES daily sending quota is exhausted (`"Daily Quota Exhausted (X/Y). Try again later."`)

Idempotency

Use idempotencyKey to safely retry without sending duplicate emails. Keys are scoped per tenant and expire after 24 hours — after that, the same key can be reused.

// First call — email is queued
const result1 = await outbound.email.send({
  toEmail: 'user@example.com',
  fromEmail: 'noreply@company.com',
  emailSubject: 'Order Confirmation',
  htmlBody: '<h1>Order confirmed</h1>',
  idempotencyKey: 'order-confirm-1234',
});

// Second call with same key — returns the exact cached response, no duplicate sent
const result2 = await outbound.email.send({
  toEmail: 'user@example.com',
  fromEmail: 'noreply@company.com',
  emailSubject: 'Order Confirmation',
  htmlBody: '<h1>Order confirmed</h1>',
  idempotencyKey: 'order-confirm-1234',
});

// result1.jobId === result2.jobId ✓
// result2.duplicate === true

How it works

The key is locked when the request starts processing. If a second request arrives with the same key while the first is still in-flight, it returns 409 Conflict.
Once the first request completes, subsequent calls return the exact same response (same jobId, messageId) with duplicate: true.
After 24 hours, the key expires and can be reused for a new send.
If the original request fails (validation error, SES quota exhausted, etc.), the key is released so you can retry immediately.
Keys are stored in Postgres (durable) and cached in Redis for fast lookups. Redis eviction under memory pressure is safe — the system falls back to Postgres automatically.

Generating Good Idempotency Keys

The key should be deterministic — the same logical send should always produce the same key. This way, retries automatically deduplicate without you tracking state.

Single email — combine the purpose + recipient:

import { createHash } from 'crypto';

// Transactional: one email type per order
const key = createHash('sha256')
  .update(`order-confirmation:${orderId}:${recipientEmail}`)
  .digest('hex');

await outbound.email.send({
  toEmail: recipientEmail,
  fromEmail: 'noreply@company.com',
  emailSubject: 'Order Confirmed',
  htmlBody: '<h1>Thanks for your order</h1>',
  idempotencyKey: key,
});

Bulk email — use the batch identity (a single key covers the whole batch):

// Campaign: one key for the entire batch
const key = createHash('sha256')
  .update(`newsletter:march-2026:batch-1`)
  .digest('hex');

await outbound.email.bulk({
  fromEmail: 'news@company.com',
  emailSubject: 'March Newsletter',
  idempotencyKey: key,
  emails: recipients,
});

Same key = same request

The idempotency key represents the entire API call, not individual recipients. If you send 100 emails with key "abc", then call again with 300 emails and the same key "abc", the second call returns the cached response from the first — it does not send to the extra 200.

Example: Bulk Sends for a Campaign

Suppose you're running campaign COM-0001 and sending to 1,200 recipients. Since the bulk API accepts max 500 per call, you'd split into 3 batches. Each batch needs its own idempotency key:

import { createHash } from 'crypto';

const campaignId = 'COM-0001';
const allRecipients = [ /* 1,200 recipients */ ];

// Split into batches of 500
const batchSize = 500;
const batches = [];
for (let i = 0; i < allRecipients.length; i += batchSize) {
  batches.push(allRecipients.slice(i, i + batchSize));
}

// Send each batch with a unique, deterministic key
for (let i = 0; i < batches.length; i++) {
  const key = createHash('sha256')
    .update(`${campaignId}:batch-${i + 1}`)
    .digest('hex');
  // COM-0001:batch-1 → "a3f8b2..."
  // COM-0001:batch-2 → "7c1d4e..."
  // COM-0001:batch-3 → "9e2f1a..."

  await outbound.email.bulk({
    fromEmail: 'campaigns@yourcompany.com',
    emailSubject: 'Exclusive Offer from YourCompany',
    senderName: 'YourCompany',
    idempotencyKey: key,
    emails: batches[i].map(r => ({
      toEmail: r.email,
      htmlBody: `<h1>Hi ${r.name}</h1><p>Your exclusive offer...</p>`,
    })),
  });
}

// Safe to retry the entire loop — batches that already succeeded
// will return the cached response with duplicate: true

Why this works:

Each batch gets a deterministic key based on campaign + batch number
If your process crashes after batch 2, you can restart the loop — batches 1 and 2 return instantly as duplicates, batch 3 sends normally
The same campaign can never accidentally double-send a batch within 24 hours

Attachments

import { readFileSync } from 'fs';

await outbound.email.send({
  toEmail: 'user@example.com',
  fromEmail: 'noreply@company.com',
  emailSubject: 'Your Invoice',
  htmlBody: '<p>Please find your invoice attached.</p>',
  attachments: [
    {
      filename: 'invoice-march-2026.pdf',
      content: readFileSync('./invoice.pdf').toString('base64'),
      contentType: 'application/pdf',
    },
    {
      filename: 'logo.png',
      content: readFileSync('./logo.png').toString('base64'),
      contentType: 'image/png',
    },
  ],
});

Attachment Limits

Max 10MB per individual attachment
Max 25MB total per email
Content must be base64 encoded

Send Bulk Emails

Send up to 500 emails in a single API call. Each recipient can have a different HTML body and subject.

const result = await outbound.email.bulk({
  fromEmail: 'noreply@yourcompany.com',
  emailSubject: 'Monthly Newsletter',
  senderName: 'YourCompany',
  replyTo: 'newsletter@yourcompany.com',
  priority: 'low',                          // 'critical'|'urgent'|'high'|'normal'|'low'|'deferred'|'backlog' (default: 'normal')
  emails: [
    {
      toEmail: 'alice@example.com',
      htmlBody: '<h1>Hi Alice</h1><p>Your personalized content here.</p>',
    },
    {
      toEmail: 'bob@example.com',
      htmlBody: '<h1>Hi Bob</h1><p>Different content for Bob.</p>',
      subject: 'Bob, check this out!',  // overrides emailSubject for this recipient
    },
    {
      toEmail: 'charlie@example.com',
      htmlBody: '<h1>Hi Charlie</h1>',
      metadata: { segment: 'vip' },
    },
  ],
});

Parameters

Field	Type	Required	Description
`fromEmail`	`string`	Yes	Sender email (verified domain)
`emailSubject`	`string`	Yes	Default subject for all recipients
`emails`	`BulkEmailRecipient[]`	Yes	Array of recipients (max 500)
`senderName`	`string`	No	Display name
`replyTo`	`string`	No	Reply-to address
`priority`	`string`	No	`'critical'`, `'urgent'`, `'high'`, `'normal'` (default), `'low'`, `'deferred'`, or `'backlog'` — queue priority for the whole batch, draining highest-urgency first in that order. `'critical'`/`'urgent'`/`'high'` bypass send pacing; `'normal'` and below are paced. Unrecognized values are treated as `'normal'`. Use `'backlog'`/`'deferred'` for large backfill campaigns so transactional sends jump ahead.
`idempotencyKey`	`string`	No	Prevents duplicate bulk sends — expires after 24 hours
`campaignId`	`string`	No	Tag this batch as part of a campaign — enables bulk cancellation via `email.cancel()`

Routing campaigns across vendors? See Global Quota for the full check → send → fall back recipe.

Recipient Object

Field	Type	Required	Description
`toEmail`	`string`	Yes	Recipient email address
`htmlBody`	`string`	Yes	HTML body for this specific recipient
`subject`	`string`	No	Override the default `emailSubject` for this recipient
`textBody`	`string`	No	Plain text alternative
`ccEmail`	`string`	No	CC recipient
`bccEmail`	`string`	No	BCC recipient
`metadata`	`object`	No	Custom metadata for this recipient

Response

{
  message: 'Bulk email queued successfully',
  jobId: '550e8400-e29b-41d4-a716-446655440000',
  recipientCount: 485,      // actual emails that will be sent
  suppressedCount: 12,      // emails filtered out (on suppression list)
  suppressedEmails: [       // which emails were suppressed
    'bounced@example.com',
    'complained@example.com'
  ],
  recipients: [             // per-recipient messageId mapping
    { toEmail: 'a@example.com', messageId: '660e8400-...', status: 'queued' },
    { toEmail: 'bounced@example.com', messageId: '660e8401-...', status: 'suppressed' }
  ],
  duplicatesRemoved: 3      // duplicate toEmails that were deduplicated
}

Duplicate responses are fully populated

When an idempotencyKey is provided and the same request is replayed, the response returns duplicate: true with the same recipients and suppressedEmails as the original. The per-recipient messageId mapping is rebuilt from the job's stored recipient rows (it isn't kept in the idempotency cache), so idempotent retries don't lose it.

On a replay, each recipient's status reflects its live state at replay time — if the worker has already processed the job, you may see sent, delivered, failed, etc. rather than queued. (suppressed recipients stay suppressed.) The first, live response always reports sendable recipients as queued.

Automatic Filtering

The platform automatically handles:

Deduplication — If you include the same toEmail twice, only the first occurrence is kept
Suppression filtering — Emails on your suppression list (bounces, complaints, manual suppressions, unsubscribes) are silently removed from the send but persisted as dropped recipient rows on the job, so you can audit them via email.status(jobId)
Quota reservation — Only valid, non-suppressed recipients count against your quota

All-suppressed batches still succeed

If every recipient in a bulk call is on the suppression list, the request still returns 202 Accepted with a jobId. No emails are sent, recipientCount is 0, and every suppressed address is persisted as a dropped row — query the job to see them.

Possible Errors

Error	Status	Cause
`BadRequestError`	400	Empty `emails` array, exceeds 500 limit, missing required fields
`ForbiddenError`	403	Domain not verified, tenant suspended
`ConflictError`	409	Idempotency key is currently being processed by another request
`RateLimitError`	429	Exceeded rate limit, or the global AWS SES daily sending quota is exhausted

Check Job Status

Track the delivery status of every recipient in a job.

const status = await outbound.email.status('550e8400-e29b-41d4-a716-446655440000');

Response

{
  job: {
    id: '550e8400-e29b-41d4-a716-446655440000',
    tenant_id: 'uuid',
    total_recipients: 500,
    status: 'completed',       // 'queued' | 'processing' | 'completed' | 'failed'
    priority: 'normal',
    created_at: '2026-03-08T10:00:00.000Z',
    updated_at: '2026-03-08T10:01:00.000Z'
  },
  recipients: [
    {
      message_id: '660e8400-e29b-41d4-a716-446655440001',
      recipient_email: 'alice@example.com',
      status: 'delivered',
      ses_message_id: 'aws-ses-message-id',
      error_message: null,
      created_at: '2026-03-08T10:00:00.000Z'
    },
    {
      message_id: '660e8400-e29b-41d4-a716-446655440002',
      recipient_email: 'bad-address@example.com',
      status: 'bounced',
      ses_message_id: 'aws-ses-message-id',
      error_message: null,
      created_at: '2026-03-08T10:00:00.000Z'
    },
    {
      message_id: '660e8400-e29b-41d4-a716-446655440003',
      recipient_email: 'invalid@nonexistent.tld',
      status: 'failed',
      ses_message_id: null,
      error_message: 'Email address not verified',
      created_at: '2026-03-08T10:00:00.000Z'
    }
  ]
}

Check a Single Message's Status

Look up the current status of one message by its messageId — the ID returned from send() / bulk() and included in webhook payloads. This is the way to reconcile a message whose webhook was missed.

Accepts only a message ID — not a job ID or SES message ID. The message must belong to the tenant your API key is scoped to, otherwise a NotFoundError is thrown.

const result = await outbound.email.getMessageStatus('660e8400-e29b-41d4-a716-446655440001');

Response

{
  recipient: {
    message_id: '660e8400-e29b-41d4-a716-446655440001',
    job_id: '550e8400-e29b-41d4-a716-446655440000',
    recipient_email: 'alice@example.com',
    from_email: 'hello@yourdomain.com',
    sender_name: 'Your App',
    subject: 'Welcome!',
    status: 'delivered',
    ses_message_id: 'aws-ses-message-id',
    error_message: null,
    created_at: '2026-03-08T10:00:00.000Z',
    updated_at: '2026-03-08T10:01:00.000Z'
  }
}

The status reflects the latest event recorded for the message by the SES event pipeline (configuration-set event destinations → stored events), so the stored status already reflects the most recent delivery/open/click/bounce SES has reported.

Recipient Status Reference

Status	Description	Final?
`queued`	Waiting in the queue	No
`processing`	Being sent to AWS SES	No
`sent`	SES accepted the email	No
`delivered`	Delivered to recipient's mailbox	Yes
`bounced`	Hard or soft bounce	Yes
`complained`	Recipient reported as spam	Yes
`opened`	Recipient opened the email	No (can become `clicked`)
`clicked`	Recipient clicked a link	Yes
`failed`	Failed to send to SES	Yes
`cancelled`	Cancelled before sending via `email.cancel()`	Yes
`dropped`	Recipient was on the suppression list at submit time — never attempted. `error_message` is `Suppressed: <bounce\|complaint\|manual\|unsubscribe>`	Yes

Status Updates

Statuses update asynchronously as AWS SES sends delivery notifications back to the platform. sent → delivered can take a few seconds to a few minutes. opened and clicked events depend on tracking being enabled and may arrive hours later.

Polling Example

async function waitForDelivery(jobId: string, maxAttempts = 10) {
  for (let i = 0; i < maxAttempts; i++) {
    const { recipients } = await outbound.email.status(jobId);

    const allDone = recipients.every(r =>
      ['delivered', 'bounced', 'complained', 'failed', 'cancelled', 'dropped'].includes(r.status)
    );

    if (allDone) {
      const delivered = recipients.filter(r => r.status === 'delivered').length;
      console.log(`${delivered}/${recipients.length} delivered`);
      return recipients;
    }

    await new Promise(resolve => setTimeout(resolve, 2000));
  }

  throw new Error('Timed out waiting for delivery');
}

Possible Errors

Error	Status	Cause
`NotFoundError`	404	Job ID doesn't exist or belongs to a different tenant
`AuthenticationError`	401	Invalid API key

Fetch a Message's Sent Content

Fetch the content that was sent for one message by its messageId — the subject, envelope and htmlBody / textBody. This is the same content the dashboard renders in its Preview, so you can reconstruct or re-display a sent email in your own UI.

htmlBody is returned as sent, including the unsubscribe footer the platform appends. Attachments are not inlined. Accepts only a message ID — not a job ID or SES message ID — and the message must belong to the tenant your API key is scoped to, otherwise a NotFoundError is thrown.

const content = await outbound.email.getMessageContent('660e8400-e29b-41d4-a716-446655440001');

Response

{
  messageId: '660e8400-e29b-41d4-a716-446655440001',
  jobId: '550e8400-e29b-41d4-a716-446655440000',
  status: 'delivered',
  subject: 'Welcome to Acme',
  fromEmail: 'hello@yourdomain.com',
  senderName: 'Your App',
  replyTo: 'support@yourdomain.com',
  toEmail: 'alice@example.com',
  ccEmail: null,
  bccEmail: null,
  htmlBody: '<html>...as sent, incl. unsubscribe footer...</html>',
  textBody: 'Plain-text alternative, or null',
  createdAt: '2026-03-08T10:00:00.000Z',
  sentAt: '2026-03-08T10:00:02.000Z'
}

Rendering the Preview

const { htmlBody, subject } = await outbound.email.getMessageContent(messageId);

// e.g. render inside a sandboxed iframe in your dashboard
iframe.srcdoc = htmlBody ?? '';
document.querySelector('#subject').textContent = subject ?? '(no subject)';

Possible Errors

Error	Status	Cause
`BadRequestError`	400	`messageId` is not a valid UUID
`NotFoundError`	404	No message with this Message ID for this tenant
`AuthenticationError`	401	Invalid API key

Cancel a Campaign or Job

Stop queued emails before they are sent. Use this when emails were triggered for the wrong audience or need to be aborted.

// Cancel all jobs belonging to a campaign
await outbound.email.cancel({ campaignId: 'launch-2026-q2' });

// Cancel a single specific job
await outbound.email.cancel({ jobId: '550e8400-e29b-41d4-a716-446655440000' });

How cancellation works

Only recipients still in queued or processing state are cancelled. Recipients already sent or delivered cannot be recalled — cancellation is not an unsend.

The platform does two things on cancel:

Marks recipients as cancelled in the database — the worker checks this and skips them
Removes the job from the queue if it hasn't started yet (removedFromQueue in the response tells you how many were removed this way)

Using `campaignId` for bulk cancellation

Pass campaignId when sending to group multiple API calls under one campaign. A single cancel() call then stops all of them:

// Send in 3 batches, all tagged to the same campaign
for (let i = 0; i < batches.length; i++) {
  await outbound.email.bulk({
    fromEmail: 'campaigns@company.com',
    emailSubject: 'Spring Sale',
    campaignId: 'spring-sale-2026',   // same ID across all batches
    emails: batches[i],
  });
}

// Oops — wrong audience. Cancel everything.
const result = await outbound.email.cancel({ campaignId: 'spring-sale-2026' });
console.log(`Cancelled ${result.cancelledRecipients} recipients across ${result.cancelledJobs} jobs`);

This also works with template sends:

await outbound.templates.bulkSend({
  templateId: 'promo-template',
  fromEmail: 'campaigns@company.com',
  campaignId: 'spring-sale-2026',
  recipients: [ ... ],
});

await outbound.email.cancel({ campaignId: 'spring-sale-2026' });

Parameters

Field	Type	Required	Description
`campaignId`	`string`	One of	Cancel all jobs tagged with this campaign ID
`jobId`	`string`	One of	Cancel a single specific job

Response

{
  message: 'Cancelled successfully',
  cancelledJobs: 3,           // number of EmailJob records cancelled
  cancelledRecipients: 1420,  // individual recipients set to 'cancelled'
  removedFromQueue: 2         // jobs removed from BullMQ before processing started
}

Possible Errors

Error	Status	Cause
`BadRequestError`	400	Neither `campaignId` nor `jobId` provided
`NotFoundError`	404	No jobs found for this tenant matching the criteria
`ConflictError`	409	All matching jobs are already completed, failed, or cancelled

Email ​

Send Single Email ​

Full Parameters ​

Parameters Reference ​

Response ​

Possible Errors ​

Idempotency ​

Generating Good Idempotency Keys ​

Example: Bulk Sends for a Campaign ​

Attachments ​

Send Bulk Emails ​

Parameters ​

Recipient Object ​

Response ​

Automatic Filtering ​

Possible Errors ​

Check Job Status ​

Response ​

Check a Single Message's Status ​

Response ​

Recipient Status Reference ​

Polling Example ​

Possible Errors ​

Fetch a Message's Sent Content ​

Response ​

Rendering the Preview ​

Possible Errors ​

Cancel a Campaign or Job ​

How cancellation works ​

Using campaignId for bulk cancellation ​

Parameters ​

Response ​

Possible Errors ​

Email

Send Single Email

Full Parameters

Parameters Reference

Response

Possible Errors

Idempotency

Generating Good Idempotency Keys

Example: Bulk Sends for a Campaign

Attachments

Send Bulk Emails

Parameters

Recipient Object

Response

Automatic Filtering

Possible Errors

Check Job Status

Response

Check a Single Message's Status

Response

Recipient Status Reference

Polling Example

Possible Errors

Fetch a Message's Sent Content

Response

Rendering the Preview

Possible Errors

Cancel a Campaign or Job

How cancellation works

Using `campaignId` for bulk cancellation

Parameters

Response

Possible Errors