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Transactional Email API for product teams

Send verification codes, password resets, invoices, onboarding nudges, and product notifications from one predictable API surface, with domain authentication, templates, logs, and webhooks close by.

Start sending freeRead quickstart
  • Verified-domain sending
  • Scoped API keys
  • Templates, tags, and attachments
  • Logs and signed webhooks
email api request
ready
request.tsPOST /v1/emails
await sendix.emails.send({
  from: "[email protected]",
  to: ["[email protected]"],
  subject: "Your login code",
  template: "login-code",
  data: { code: "742913" },
  tags: ["auth", "critical"]
});
JSONTemplateWebhook
API call
accepted
domain
signed
message
queued
event emitted
delivered
Production flow

From app event to inbox, without building a mail stack.

The Email API is designed for teams that want a narrow send contract and a clear operational trail after submission.

01
DNS checks

Authenticate the domain

Add the domain once, publish DNS records, and let Sendix guide SPF, DKIM, and DMARC alignment.

02
email:send

Create a scoped key

Issue API keys for the exact surface your app needs and keep the plaintext secret in your vault.

03
POST /v1/emails

Submit JSON

Call POST /v1/emails with HTML, text, templates, tags, scheduled time, and attachments.

04
Events

Observe the lifecycle

Follow queued, delivered, bounced, complained, opened, and clicked events from logs or webhooks.

Developer experience

A send API that fits into workers, queues, and product backends.

Keep product logic in your codebase and let Sendix handle the email delivery surface: authentication, payload validation, domain signing, delivery logs, and event callbacks.

  • REST first

    Use simple JSON from any runtime. The same endpoint covers raw HTML, text, templates, tags, and attachments.

  • Structured errors

    Validation failures come back as predictable API responses, so forms, queues, and workers can react cleanly.

  • Replay-friendly events

    Webhook delivery state and logs give your team a clear trail when a downstream service misses an event.

import { Sendix } from 'sendix-node';

const sendix = new Sendix({ apiKey: process.env.SENDIX_KEY });

const { id } = await sendix.emails.send({
  from: '[email protected]',
  to: ['[email protected]'],
  subject: 'Welcome aboard!',
  html: '<h1>Hi there</h1><p>Thanks for signing up.</p>',
});

console.log('Queued:', id);
API surface

One send contract, enough context for production support.

Each block highlights the operational context developers need after the first message leaves the application.

Transactional payloads

Verification, password reset, billing, onboarding, and product notifications use the same send contract.

Templates without lock-in

Send with template ids when content belongs in Sendix, or keep markup in your app and pass HTML directly.

Preflight checks

Run spam risk checks before a large rollout or a sensitive template launch.

Signed webhooks

Subscribe to delivery events and verify signatures before updating your own product state.

Operational logs

Search sent messages, inspect outcomes, and connect API requests to delivery activity.

Endpoint map

Start with sending, then add the controls your workflow needs.

The public API keeps core resources readable: messages, templates, domains, webhooks, and supporting checks each have their own documented path.

Open API reference
MethodPath
POST/v1/emailsemail:sendSubmit a transactional message.
POST/v1/emails/spam-checkemail:sendCheck content risk before sending.
GET/v1/emailsemail:readReview recent message activity.
GET/v1/templatestemplates:readRead reusable content blocks.
POST/v1/webhookswebhooks:writeSubscribe your app to lifecycle events.
Same pricing as the rest of Sendix

Build on the Email API without a separate developer tax.

The free tier includes 25,000 emails per month. Paid plans keep the same API surface, so upgrading changes volume and limits, not your integration.

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FAQ

Practical answers for the first integration review.

Short notes for the questions developers usually ask before wiring a transactional provider into production.

Can I use Sendix without changing my app architecture?

Yes. Use the REST Email API from your workers, product backend, or queue consumers. If a system already speaks SMTP, Sendix also supports authenticated SMTP submission.

Does the Email API require a verified domain?

Production sending should use a verified domain. Sendix shows the DNS records and tracks domain authentication so SPF, DKIM, and DMARC alignment are visible.

Can one endpoint handle templates and raw HTML?

Yes. Your app can send raw HTML and text, or reference a template when the content should be managed inside Sendix.

How do developers track delivery?

Use message logs for inspection and signed webhooks when your application needs to react to delivered, bounced, complained, opened, or clicked events.

Ready to send your first email?

25,000 emails free every month. No credit card required. Upgrade only when you outgrow the free tier — and we will let you know when that time comes.

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Managed SaaS platform · Native SMTP engine · SOC 2 in progress