SMTP for your website and app

Send website emails
through SendMailOS.

Connect your app or WordPress mail plugin to send form notifications, receipts, and other application emails through your configured sending route.

Create your account Explore the email API

Your SMTP connection

Host

smtp.sendmailos.com

Username

sendmailos

STARTTLS

Port 2525

SSL/TLS

Port 2465

Create a sending-only SMTP password in your dashboard under API Keys → SMTP. Use a verified From address on the selected domain and turn on TLS encryption and authentication.

Port 25 is not used for submission. SMTP attachments are not supported yet. Use the current dashboard settings when configuring your client.

Connect in three steps

Verify your domain

Add the sending domain and complete its verification. Choose an allowed From address on that domain.

Create your SMTP password

Open API Keys → SMTP and create a sending-only password. Limit it to a domain when you need a narrower credential.

Configure and test your app

Enter the host, username, password, port, and matching TLS option. Your client must support custom ports 2525 or 2465. Send a test message and check its delivery status.

One connection. Your selected delivery route.

Hosted delivery or your own server.

SMTP follows the route configured for your selected domain: SES, a connected server, or hybrid. Check the route before you send.

A message sent through your connected VPS has no platform per-email charge and uses no hosted credit. Hosted delivery uses the allowance in your plan. Starter includes one server connection for €12/month.

See own-server sending

Connect your own sending server and IP to SendMailOS, with no platform per-email fee on a paid plan — Product illustration · Example setup

Choose SMTP or the API

Use SMTP with existing mail tools

A practical option when your website or application already accepts custom SMTP settings. Use it for supported messages without SMTP attachments.

Use the HTTP API from your backend

Choose the API for HTTP requests, message IDs, templates, idempotency keys, and delivery event handling. See API tools

SMTP fits into your sending plan

Start free, or connect your own sending server from €12/month. Every paid plan also includes a monthly hosted sending allowance.

Free

Build and test your first campaigns.

€0 / month

Hosted emails: 3,000
Active subscribers: 2,000
Sending domains: 1
Tracking pixels: 1
Own servers: —

Hosted delivery uses your monthly email allowance.

Start free

Starter

For one brand ready to send regularly.

€12 / month

Hosted emails: 25,000
Active subscribers: 10,000
Sending domains: 3
Tracking pixels: 3
Own servers: 1

€0 platform fee per email sent through your own server.

Choose Starter

Growth

For teams managing more brands and workflows.

€39 / month

Hosted emails: 100,000
Active subscribers: 50,000
Sending domains: 10
Tracking pixels: 10
Own servers: 3

€0 platform fee per email sent through your own server.

Choose Growth

Pro

For larger audiences and more sending infrastructure.

€99 / month

Hosted emails: 250,000
Active subscribers: 250,000
Sending domains: 50
Tracking pixels: 50
Own servers: 10

€0 platform fee per email sent through your own server.

Choose Pro

Prices shown per month in EUR. A hosted email uses one send per recipient. Own-server delivery does not use hosted credits. Your VPS costs and other plan limits still apply.

See every plan limit

SMTP questions

Which SMTP host and ports should I use?

Use smtp.sendmailos.com. Select STARTTLS on port 2525 or implicit SSL/TLS on port 2465. Enable authentication and use the SMTP credentials created in your workspace. Port 25 is not a submission port.

Can I connect WordPress?

Yes. Use a WordPress mail plugin that lets you configure a custom SMTP host, port, encryption, username, and password. Use the ports and credentials shown above, then send a test message.

Can I send attachments through SMTP?

SMTP attachments are not supported yet. Check the current product documentation before choosing SMTP for a workflow that needs attachments.

Which route sends my SMTP email?

Delivery follows the selected domain’s configured route: SES, a connected server, or hybrid. Use a verified From address on that domain. Own-server sends do not consume hosted credits; hosted delivery uses your plan’s allowance.

Is my SMTP password the same as my login password?

No. Create a sending-only SMTP password in API Keys → SMTP in your dashboard. You can limit the credential to a domain. Keep it on your application server or in your mail plugin’s protected settings.

Does an accepted SMTP message guarantee delivery?

No. Acceptance is not an inbox guarantee. Check email status and delivery events to understand the delivery result.

Choose the right sending route

Server only

Messages wait for your connected server when it is offline. This route can accept SMTP mail even when you have no hosted credits, and cannot fall back to hosted delivery.

Hybrid with hosted fallback

A hybrid route needs a hosted credit because it may use SES when your server is unavailable. Messages actually sent through your server have their reserved hosted credit returned.

Connect your first application

Create your account, verify a sending domain, and test one message.

Create your account Compare plans