Checking service status…

Enterprise-Grade Email Delivery Infrastructure

Reliable, scalable, and secure SMTP relay service for businesses of all sizes. Send millions of emails with confidence.

Start Free Trial Why Choose Us

99.9%

Uptime

100B+

Emails Delivered

<1s

Avg Delivery Time

98.7%

Delivery Rate

12.6M

Sent Today

0.3%

Bounce Rate

Real-time delivery analytics dashboard

S: 220 smtp01.smtps.io ESMTP

C: EHLO app.yourdomain.com

S: 250-STARTTLS · 250 AUTH PLAIN LOGIN

C: STARTTLS → 220 Ready to start TLS

C: AUTH LOGIN ••••••••

S: 235 Authentication successful.

C: MAIL FROM:<hello@yourdomain.com>

S: 250 Ok

C: DATA → 250 Ok

DKIM

SPF

DMARC

TLS / STARTTLS

99.9% uptime <1s delivery Auto failover Dedicated IPs

Manage Everything in One Dashboard

Features

Why Choose SMTPS.IO?

Built for developers and businesses who demand reliability

High Deliverability

Our advanced infrastructure ensures your emails reach the inbox, not spam folders.

Enterprise Security

TLS encryption, DKIM signing, SPF, and DMARC support out of the box.

Real-time Analytics

Track deliveries, opens, clicks, and bounces in real-time.

Developer Friendly

RESTful API, webhooks, and comprehensive documentation.

Scalable Infrastructure

Handle millions of emails per day with our auto-scaling architecture.

24/7 Support

Expert support team available around the clock.

Use Cases

One platform for every email you send

From a single password reset to million-recipient campaigns — delivered fast and straight to the inbox.

Transactional Email

Password resets, order confirmations and receipts that arrive the instant your users expect them.

Marketing Campaigns

Send newsletters and promotions at scale with reputation controls that keep you out of spam.

OTP & 2FA Codes

Time-critical one-time passcodes delivered in under a second, every time it matters.

Notifications & Alerts

Account, system and activity alerts your customers can depend on around the clock.

Invoices & Statements

Billing documents and statements that reliably reach inboxes with full delivery tracking.

Onboarding & Verification

Welcome and email-verification messages that drive sign-ups all the way to activation.

Deliverability

Engineered to land in the inbox

Authentication, encryption and reputation management are built in — so the inbox, not the spam folder, is where your mail ends up.

Automatic DKIM signing with SPF & DMARC alignment
TLS encryption on every connection
Dedicated IPs with smart, automated warm-up
Real-time reputation, bounce & complaint monitoring
Built-in spam-complaint and unsubscribe handling

Your App & Website

Send via SMTP relay or REST API

SMTPS.IO
Signs, secures & intelligently routes every message

                                    DKIM
                                    SPF
                                    DMARC
                                    TLS
                                

Global Mailbox Providers

Gmail · Outlook · Yahoo · and more

Recipient Inbox

Delivered in under a second

Automatic Warm-Up

Every new domain and IP is warmed up for you

Mailbox providers are wary of senders that appear out of nowhere at high volume. SMTPS.IO ramps every new sending domain and IP up step by step, and shows you where you stand each day.

yourbrand.com

Warm-up · Day 6 of 21

Today 1,240 of 3,000 sent

Advisory: you see the plan for each day, and no message is ever held back.

Example: a new domain on the standard 21-day plan

A 21-day plan for every new domain

Add a sending domain and its warm-up starts on its own: 200 emails on day 1, rising to 550,000 a day by day 21. A day only counts when you actually send.

Advisory or Paced: you choose

Advisory shows the recommended volume and never blocks a message. Switch to Paced and we hold each day to the plan: messages over it get a temporary “try again later” reply until the next UTC day.

New IPs warm up too

Every new sending IP on our network ramps up over 14 days before it takes its full share, while proven IPs carry the rest of your mail.

Track it in your dashboard

Each domain shows its warm-up day and today’s volume against the plan, with the full schedule one click away. Already have a sending history? Skip the warm-up at any time.

How It Works

Get started in minutes

Simple setup process to start sending emails in no time.

Sign Up

Create your account and get your API credentials instantly.

Configure

Set up your domains, authentication, and sending preferences.

Send

Start sending emails through our SMTP servers or API.

send_email.py

# Send your first email in seconds
import smtplib
from email.message import EmailMessage

msg = EmailMessage()
msg["From"]    = "you@yourdomain.com"
msg["To"]      = "customer@example.com"
msg["Subject"] = "Hello from SMTPS.IO"
msg.set_content("Your email, delivered.")

with smtplib.SMTP("smtps.io", 2525) as s:
    s.starttls()                       # encrypt the connection (TLS)
    s.login("your-username", "your-password")
    s.send_message(msg)

Integration

Connect in minutes, not days

Standard SMTP and a clean REST API mean SMTPS.IO drops straight into the stack you already use — no rewrites, no lock-in.

Standard SMTP on port 2525 — STARTTLS supported, works with any language or framework
REST API & webhooks for sends, events and analytics
Drop-in replacement for your current mail provider

Node.js Python PHP Java Ruby WordPress .NET Go

Testimonials

Loved by Developers & Businesses

"Switching to SMTPS.IO was the best decision for our email infrastructure. Deliverability improved by 40% in the first month."

John Davis

CTO, TechStartup Inc.

"The analytics dashboard is incredible. We can now track every email and optimize our campaigns in real-time."

Sarah Miller

Marketing Director, GrowthCo

"Setup took less than 10 minutes. The documentation is clear and support team is incredibly responsive."

Michael Kim

Lead Developer, AppWorks