✉ Transactional Email API

Ship email that
actually arrives.

1,000 transactional emails per month through our 10/10-rated deliverability MTA. REST API or SMTP submission. API key in under a minute. No warm-up. No DNS headaches.

10/10
mail-tester score
0.2
SpamAssassin
1,000
emails / month
$19
per month

Two lines to send.

Use plain JSON or drop in SMTP credentials. Your app controls the display name and reply path; transport runs through vøiddo's mailer identity.

SMTP quick start

Hostmailer.voiddo.com
Port2525
SecuritySTARTTLS
Usernameyour billing email
Passwordyour API key
curl -X POST https://mailer.voiddo.com/api/v1/send \
  -H "Authorization: Bearer vmd_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
    "to": "user@example.com",
    "from_name": "My App",
    "from_email": "noreply@myapp.com",
    "subject": "Welcome aboard!",
    "html": "<p>Thanks for signing up.</p>"
  }'

# Response: {"sent": true, "used": 1, "quota": 1000}

Built for founders who ship.

Everything you need, nothing you don't.

📬

10/10 deliverability

Our MTA scored 10/10 on mail-tester.com with a SpamAssassin score of 0.2. SPF, DKIM, and DMARC all passing.

Instant API key

Subscribe, get your API key in the confirmation email. No dashboard setup, no domain verification required.

📊

Quota dashboard

Check how many emails you've used this month at any time. Simple status endpoint or our web dashboard.

🔁

Reply-To passthrough

Set your app's address as Reply-To so replies land in your inbox, while delivery stays on vøiddo's sending identity.

🔒

Zero cold outreach

This relay is for transactional mail only: welcome emails, receipts, alerts. Not for bulk campaigns.

🛠

REST + SMTP relay

POST JSON if you want the thinnest path, or plug in SMTP on mailer.voiddo.com:2525 with STARTTLS if your app already speaks SMTP.

Simple pricing.

One plan. 1,000 emails per month. Cancel anytime.

Starter
$19
per month · billed monthly
  • 1,000 transactional emails / mo
  • Instant API key on subscription
  • SMTP relay on mailer.voiddo.com:2525
  • 10/10 deliverability MTA
  • Usage dashboard
  • Reply-To passthrough
  • Cancel anytime
  • Support at support@voiddo.com
Subscribe — $19/mo

Secure checkout via Paddle on extensions.voiddo.com · VAT handled automatically

FAQ

What counts as a transactional email? +
Welcome emails, password resets, receipts, order confirmations, alerts, notifications — any email triggered by user action in your app. Bulk marketing campaigns and cold outreach are not permitted.
What happens when I hit 1,000 emails? +
The API returns a 429 error with a clear message. Your quota resets at the start of the next billing month. We don't auto-charge overages — you stay in control.
How do I connect over SMTP? +
Use mailer.voiddo.com on port 2525 with STARTTLS. Username is your billing email. Password is the API key we send after subscription activation. Your visible sender name comes from the From: header you submit; delivery still rides on vøiddo's sending identity for deliverability.
What does the email look like to my users? +
Recipients see your chosen display name, and replies go to the from_email you send in the payload via Reply-To. Transport is handled by vøiddo's mail identity for deliverability, so this is best for product mail, receipts, alerts, and other transactional flows where branded reply handling matters more than a custom sender domain.
Do I need to set up SPF or DKIM? +
No. Our MTA's SPF and DKIM are already configured and passing. You don't touch DNS at all.
Can I cancel anytime? +
Yes. Cancel through Paddle's billing portal at any time. No lock-in, no cancellation fee.
Who is vøiddo? +
vøiddo is an indie software studio building tools for developers and founders. We run our own mail infrastructure for our products — this SaaS lets you tap into that same stack.