Purpose-built IoT SMTP relay

Email from your devices.
Finally done properly.

Dedicated SMTP relay built for IoT and M2M. Per-device credentials, TLS enforced, Amazon SES backbone. UK-based and GDPR-compliant.

Start free - no card needed See how it works
587/465
TLS-only ports
£0
To get started
5min
Device setup time
SES
Relay backbone
How it works

Up and running in five minutes

Register once. Add your devices. Copy the credentials into firmware. That is it.

01 📝
Register
Email and password. No card required. Account active immediately after verification.
02 ✉️
Verify email
Click the confirmation link. Your account is live. Takes under a minute.
03 🏷
Choose a handle
Pick your account prefix. This becomes the sender identity for all your devices.
04 📡
Add devices
Name each device in the portal. Unique SMTP credentials are generated per device.
05 ⚙️
Configure firmware
Copy host, port, username and password into your device. Send a test alert.
06 📊
Monitor
Portal shows send logs, delivery status, bounces and usage per device in real time.
Sub-addressing model

Every device has its own identity

Each device sends from a unique, traceable address. Recipients can filter and audit by sender. No configuration needed on their end.

acme+gw-001@iotmail.co.uk
acme = your account handle
gw-001 = device identifier set in portal
iotmail.co.uk = verified SPF + DKIM + DMARC domain
acme+gw-001@iotmail.co.uk Teltonika RUT241, Site A
acme+sensor-14@iotmail.co.uk Milesight AM307, Building 3
acme+reboot-mon@iotmail.co.uk Ping watchdog instance
bigcorp+tower-0847@iotmail.co.uk Enterprise fleet, unit 847 of 2,000
Per-device credentials are not a feature - they are the security model. Each device authenticates with its own username and password. Compromise one device and you revoke that credential instantly from the portal. The rest of the fleet keeps sending. Shared credentials mean one compromised device exposes everything. We do not offer shared credentials.
Platform features

Built for machines, not humans

IoT devices are not email clients. The platform is designed around that reality from the ground up.

🔒
TLS mandatory. No exceptions.
Port 25 plaintext is not accepted. All connections must use TLS 1.2 or higher on port 587 or 465. Encryption is not optional and not configurable.
🛡
From: header enforcement
The milter verifies that the From: address in every message exactly matches the authenticated device credential. A device cannot impersonate another device or any platform address.
📬
Amazon SES relay backbone
All outbound mail routes through SES. Established IP reputation, deliverability management, bounce processing, and complaint feedback loops are all handled for you.
📋
SPF, DKIM and DMARC: reject
All three are published and enforced on iotmail.co.uk. DMARC policy is reject. Spoofed emails claiming to come from this domain do not reach recipients.
⚡
Instant credential revocation
Revoke any device credential from the portal immediately. The device record and full send history are preserved. Generate a replacement credential without losing audit continuity.
📈
Per-device send logs
Every send is logged with device ID, timestamp, recipient count, delivery status and bounce data. No email body content is ever stored. GDPR-clean by design.
🌍
IP allowlisting (Pro+)
Restrict SMTP connections to specific source IP addresses per account. Connections from outside the allowlist are rejected before authentication is even attempted.
🔔
Silence detection
Devices that go quiet for a configurable period trigger a portal warning. The most dangerous IoT failure mode is an alert chain that has silently broken. We catch it.
🇬🇧
UK-based, GDPR-compliant
UK-domiciled platform. No email body content retained. Full account deletion on request. Data Processing Agreements available for Enterprise customers.
Security by design

Every control built in. None delegated to the customer.

Over 90% of cyberattacks use email as the vector. IoT adds a large new attack surface. These controls are not optional add-ons - they are the platform.

✓ TLS 1.2+ enforced
✓ DMARC: reject policy
✓ Per-device credentials
✓ From: header binding
✓ Fail-closed milter
✓ Reserved namespace protection
✓ Bounce rate auto-suspension
✓ IP allowlisting (Pro+)
✓ MFA available all tiers
✓ Full audit log
✓ No body content stored
✓ Volume anomaly alerting
Pricing

Start free. Scale when you need to.

No hard cutoffs. Pro and Scale accounts run over their daily limit with a small per-email overage charge rather than going silent. A fleet doubling after a rollout must not stop sending alerts.
Starter
Free / forever
No credit card
  • Devices5
  • Emails / day50
  • Log retention7 days
  • TLS enforcedYes
  • SPF/DKIM/DMARCYes
  • REST APINo
  • WebhooksNo
  • IP allowlistNo
  • MFAOptional
Get started free
MOST POPULAR
Pro
£12 / month
Free 12 months for IoT router customers
  • Devices50
  • Emails / day500
  • Log retention30 days
  • TLS enforcedYes
  • SPF/DKIM/DMARCYes
  • REST APIFull
  • WebhooksYes
  • IP allowlistYes
  • MFAOptional
Start Pro trial
Scale
£49 / month
 
  • Devices500
  • Emails / day5,000
  • Log retention90 days
  • TLS enforcedYes
  • SPF/DKIM/DMARCYes
  • REST APIFull
  • WebhooksYes
  • IP allowlistYes
  • Audit exportCSV
  • Team users5
Get Scale
Enterprise
POA
Volume + SLA pricing
  • DevicesUnlimited
  • Emails / dayUnlimited
  • Dedicated IPYes
  • Custom domainYes
  • SSO / SAMLYes
  • RBACYes
  • SLA99.9%
  • MFAEnforced
  • Log retention1 year+
Talk to us
Customer portal

Full visibility, per device

Register, add devices, generate credentials, revoke them, monitor sends and bounces - all in one place. No support tickets needed.

portal.iotmail.co.uk — Dashboard
24
Active devices
1,847
Emails this month
98.7%
Delivery rate
2
Bounces / errors
Device nameSMTP addressStatusLast send
RUT241 Site A acme+gw-001@iotmail.co.uk Active 2 min ago
CO2 Sensor B3 acme+sensor-14@iotmail.co.uk Active 14 min ago
Ping Reboot WD acme+reboot-mon@iotmail.co.uk Warning 3 hrs ago
Solar GW Roof acme+solar-rg1@iotmail.co.uk Silent 7d 7 days ago
Device support

Works with any device that supports SMTP

If it has SMTP AUTH support and can do TLS, it works with IoTMail. These brands are tested and documented.

📡
Teltonika
Industrial routers
📡
Milesight
IoT gateways
📡
Sierra Wireless
M2M routers
📡
Robustel
Industrial routers
🔄
Ping Reboot
Watchdog devices
🌡
Generic sensors
Any SMTP device
FAQ

Common questions

What is IoTMail and why do I need it?+
IoTMail is a dedicated SMTP relay built for IoT and M2M devices. Standard email providers block unknown senders, rate-limit aggressively, and require OAuth that device firmware cannot handle. IoTMail provides a relay on standard SMTP ports with AUTH credentials any device can use.
Why can't my device just send email directly?+
Three reasons. Most ISPs block outbound port 25. Dynamic SIM IP addresses have no sending reputation and get rejected by major mail providers. Without SPF, DKIM and DMARC your messages are treated as spam. IoTMail solves all three - port 587/465, Amazon SES backbone with established reputation, and full email authentication on iotmail.co.uk.
Will it work with my Teltonika / Milesight / Sierra Wireless device?+
Yes. Any device that supports SMTP AUTH with TLS works with IoTMail. We have tested and documented setup for Teltonika RUT series, Milesight UG and UC series, Sierra Wireless AirLink, and Robustel R series. See the device guides for step-by-step instructions.
What does per-device credentials mean in practice?+
Each device gets its own unique SMTP username and password. If a device is compromised, you revoke that one credential instantly from the portal. Every other device keeps sending without interruption. Shared credentials mean one compromised device exposes all of them.
Do you store the content of emails?+
No. IoTMail logs metadata only - device ID, timestamp, recipient count, and delivery status. Email subject and body are never stored. This is by design for GDPR compliance.
What happens if my device exceeds the daily email limit?+
Pro and Scale accounts run over their daily limit with a small per-email overage charge rather than going silent. Hard cutoffs in IoT infrastructure are dangerous - a fleet that doubles after a rollout must not stop sending alerts.
How long does setup take?+
Five minutes or less for most devices. Create an account, add a device, copy the SMTP credentials into your device firmware, send a test. Credentials work immediately - no waiting period, no approval process. Free Starter plan requires no card.
Is IoTMail suitable for large fleets?+
Yes. Scale plan supports 500 devices and 5,000 emails per day. Enterprise is unlimited with dedicated IP, custom domain, SSO, RBAC, and 99.9% SLA. Contact us for volume pricing on fleets in the thousands.

Your devices should be sending alerts right now.

Free account. Five devices. No card. Up and running in five minutes.

Start free today Read the docs