Connect your email via SMTP

SMTP (Simple Mail Transfer Protocol) is how mail servers accept and relay outgoing email. Once OttaBlast has your SMTP credentials, it can send campaigns from your real address with your own deliverability and reputation. That also means your provider's limits and your domain reputation matter.

1. What SMTP is & what you need

Whatever provider you use, you'll be collecting the same five values:

• Host — the server address, e.g. smtp.hostinger.com.
• Port — usually 587 (STARTTLS) or 465 (SSL/TLS).
• Username — typically your full email address, or an API/login key.
• Password — your mailbox password, an app password, or a generated SMTP key.
• Encryption — TLS/STARTTLS or SSL, matching the port above.

2. Choose your SMTP source

You have two good options:

• Your domain mailbox — the inbox that comes with your hosting or email provider (Hostinger, Google Workspace, Microsoft 365). Simplest if you're sending modest volumes.
• A transactional email provider — services built for sending at scale with the best inbox placement: Brevo, SendGrid, Mailgun, Amazon SES, Postmark. Recommended once you send thousands of emails per campaign.

If you're unsure, start with your domain mailbox for small lists and move to a transactional provider before you send large campaigns. A normal mailbox is designed for human email, not high-volume marketing. Pushing it too hard can cause SMTP errors, temporary sending blocks, or full account suspension.

3. Get your SMTP credentials

Where to find them depends on your source:

• Hostinger — in hPanel → Emails, open your account and view Configuration settings for the SMTP host, port, and username; the password is your mailbox password.
• Google Workspace / Gmail — turn on 2-Step Verification, then create an App Password and use that as the SMTP password (your normal password won't work).
• Microsoft 365 / Outlook — use smtp.office365.com on port 587 with your email and password (enable SMTP AUTH if your admin disabled it).
• Brevo / SendGrid / Mailgun — open the SMTP section of their dashboard and generate an SMTP key; that key is your password, with the username they show you.

Common defaults for reference:

Provider	Host	Port
Hostinger	smtp.hostinger.com	465 (SSL)
Gmail / Workspace	smtp.gmail.com	587 (TLS)
Microsoft 365	smtp.office365.com	587 (TLS)
Brevo	smtp-relay.brevo.com	587 (TLS)
SendGrid	smtp.sendgrid.net	587 (TLS)

4. Authenticate your domain

To stay out of spam, prove you're allowed to send from your domain by adding three DNS records at your domain registrar:

• SPF — lists the servers allowed to send for your domain.
• DKIM — cryptographically signs your mail so it can't be forged.
• DMARC — tells inboxes what to do with mail that fails the checks above.

Your SMTP provider gives you the exact record values to paste. This step is optional to send, but essential for reaching the inbox at scale.

5. Connect it in OttaBlast

1. Log in to your OttaBlast dashboard and open Settings → Email / SMTP.
2. Enter your host, port, and encryption (TLS for 587, SSL for 465).
3. Enter your username and password (or app password / SMTP key).
4. Set the From name and From email your recipients will see.
5. Save, then click Send test email to confirm it works.

When the test arrives in your inbox, you're ready to send Email Blast campaigns.

6. Sending rules to stay unblocked

Email deliverability is built on reputation. Mailbox providers (Gmail, Outlook, Yahoo) and your own SMTP host watch volume, complaints, bounces, authentication, and message content. They will throttle, block, or blacklist senders who look like spam. Follow these rules to protect your domain.

Know your provider's daily limit first

SMTP limits are set by the provider, not by OttaBlast. Check your exact plan before sending, because limits can apply per mailbox, per domain, per account, or per rolling 24-hour period. One email sent to 100 recipients may count as 100 sends.

SMTP source	Typical limit to check	Use it for
Hostinger Business Email	Often 1,000/day on Starter and 3,000/day on Premium, per mailbox.	Small campaigns from a domain mailbox.
Hostinger cPanel Email	Often 2,400/day per plan and 200/hour, depending on plan.	Small-to-medium sends with careful pacing.
Google Workspace / Gmail SMTP	Google Workspace commonly allows 2,000 messages/day per user, but SMTP recipient limits are stricter.	Business email and small campaigns, not aggressive blasting.
Microsoft 365 / Outlook SMTP	Commonly 10,000 recipients/day and 500 recipients/message per mailbox.	Business mail with controlled volume.
Brevo Free	300 emails/day.	Testing and very small campaigns.
SendGrid Free	100 emails/day during the free sending period.	Testing, then upgrade for real volume.
Mailgun, Amazon SES, Postmark, paid SendGrid/Brevo	Plan, account, region, or approved quota based.	Large campaigns after domain authentication and warmup.

For blasts to thousands of contacts, use a real email sending provider instead of a personal mailbox. Gmail, Outlook, and hosting mailboxes can work for modest sends, but they are not built to behave like bulk mail infrastructure.

Strict rules before every email blast

• Only email people who opted in. Never buy, rent, scrape, or export random lists. Unsolicited mail draws spam complaints, which is the fastest route to a blacklist.
• Authenticate your domain. SPF, DKIM, and DMARC must pass (see step 4). Gmail and Yahoo require strong authentication for bulk senders.
• Use your own domain. Send from an address like hello@yourdomain.com, not a free personal address. The domain in your From address should match the authenticated sending domain.
• Stay below the limit. Do not try to send exactly at the provider maximum. Keep a buffer for test emails, retries, bounces, normal replies, and other systems using the same mailbox.
• Warm up slowly. New domains, new mailboxes, new SMTP keys, and new dedicated IPs need gradual volume. Sudden jumps from 20 emails to 5,000 emails look suspicious.
• Offer one-click unsubscribe and honor it immediately. Required for many bulk senders and good practice for everyone. Always include a working unsubscribe link and a physical mailing address where required by law.
• Keep complaints and bounces low. Aim for a spam-complaint rate under 0.3%. Remove hard bounces, repeated soft bounces, unsubscribed contacts, and inactive addresses before each send.
• Avoid spam-like content. Do not use misleading subjects, all-caps promises, URL shorteners, too many links, suspicious attachments, or copied templates that many other senders use.
• Throttle large sends. Spread campaigns across time instead of pushing every message at once. If your provider returns rate-limit or SMTP 4xx errors, pause and reduce speed.
• Protect credentials. Use app passwords or SMTP keys where possible, rotate exposed keys, and do not share one mailbox across unrelated campaigns.

Simple volume guidance

List size	Recommended sending setup	Why
Up to a few hundred contacts	Domain mailbox SMTP can be enough.	Stay under mailbox limits and send only to opted-in contacts.
1,000 to 5,000 contacts	Use a transactional or marketing email provider.	You need better throttling, bounce handling, and deliverability tools.
5,000+ contacts/day	Use a bulk-ready provider with full SPF, DKIM, DMARC, unsubscribe, and warmup.	Major inbox providers apply stricter bulk-sender rules at this level.

7. Troubleshooting

Need a hand? Contact our team and we'll help you connect.

Related guide: sending on WhatsApp too? Learn how to get a permanent WhatsApp access token for your WhatsApp Blast campaigns.