Why does Brevo use an SMTP Key instead of my account password?

Brevo uses SMTP Keys for security and access control. An SMTP Key grants Mail AI permission to send emails only — it cannot log in to your Brevo account, access your contacts, view campaigns, or change any settings. You can revoke it at any time from your Brevo dashboard without affecting your main account. Always create a key with the minimum permission needed (Mail Send only).

What is sender verification and why is it mandatory?

Brevo requires you to confirm you own or control any email address you plan to send FROM. This protects against spam and spoofing. If your FROM email is not verified in Brevo, every send attempt will be rejected with a 'Sender not verified' error — even if all other credentials are correct. Verification takes about 30 seconds: add the address in Brevo → click the confirmation link in the email Brevo sends to that address.

Can I send from a custom domain email like info@mycompany.com?

Yes — and this is exactly what Brevo is designed for. Unlike Gmail SMTP (which can only send from a @gmail.com address), Brevo lets you send from any email address you own, including custom domain addresses like info@mycompany.com, hello@yourbrand.com, or support@yourdomain.com. Just add and verify that address as a sender in Brevo before using it in Mail AI.

How many emails can I send per day on the free Brevo plan?

Brevo's free plan allows 300 emails per day with no monthly limit on the number of days. For most small businesses using Mail AI, this is more than sufficient. If you need more volume, Brevo's Starter plan begins at around $25/month for 20,000 emails/month, and the Business plan scales up to 100,000 emails/month and adds open and click tracking features.

Will Brevo track whether my recipients open or click my replies?

Brevo does track email opens and clicks by default and makes this data visible in your Brevo dashboard under Transactional Emails. This can be useful for gauging customer engagement. If you prefer replies to be untracked (no tracking pixels or link wrapping), you can disable transactional tracking in your Brevo account settings.

What is the difference between using Brevo SMTP vs Gmail SMTP in Mail AI?

Gmail SMTP is the simplest option if you are already using a @gmail.com address — it requires no new account. However, it only works for Gmail addresses and caps at 500 emails/day. Brevo is the better choice if you want to send from a custom domain address (e.g. info@yourbusiness.com), need better deliverability for transactional mail, want open/click analytics, or are sending more than 500 replies per day.

How to Set Up Brevo SMTP for AI Email Replies in Mail AI

Brevo (formerly Sendinblue) is the recommended SMTP provider for any Mail AI user sending from a custom domain email address — like [email protected] or [email protected]. Unlike Gmail SMTP, Brevo works with any email address you own, regardless of where it is hosted.

The free plan includes 300 emails per day with no credit card required. Setup takes about 7 minutes the first time — most of that is sender verification, which Brevo requires once per FROM address.

💚 Why Brevo is recommended for business domains: Gmail SMTP can only send from a @gmail.com address. If your business uses [email protected], Brevo is the simplest path — create a free account, verify your domain email as a sender, generate one SMTP key, and you are done.

Brevo SMTP Settings at a Glance

Setting	Value
SMTP Host	`smtp-relay.brevo.com` Copy
Port	`587`
Encryption	`STARTTLS`
Username	Your Brevo account login email (not your FROM email)
Password	Your SMTP Key — starts with `xkeysib-` (NOT your Brevo login password)
FROM Email	Any email address verified as a sender in your Brevo account

⚠️ Two easy mistakes to avoid:
1. The Username is your Brevo login email — not the address you are sending from.
2. The Password is your SMTP Key (starts with xkeysib-) — not your Brevo account password. Using your Brevo login password will always fail.

Step-by-Step Setup

1

Create a free Brevo account

Go to brevo.com and sign up for a free account if you do not have one. The free plan includes 300 emails per day — enough for most small businesses. No credit card required.
Open Brevo Settings →
2

Generate a Brevo SMTP Key

In your Brevo dashboard, click the gear icon (top right) → Settings → SMTP & API (left sidebar). Under the SMTP Keys section, click "Generate a new SMTP key". Name it MailAI → click Generate. Copy the key starting with xkeysib- — it is shown only once.
Open Brevo Settings →
3

Verify your FROM email address as a sender

In Brevo, go to Settings → Senders & IPs → Add a new sender. Enter the email address you want to send FROM (e.g. [email protected]). Brevo sends a verification email to that address — click the confirmation link inside it. Brevo will reject sending if this step is skipped.
Open Brevo Settings →
4

Open Reply SMTP Setting in Mail AI

In your Mail AI dashboard, go to Linked Email Accounts. Find the email address you want to configure and click "+ Reply SMTP Setting".
Open Mail AI Dashboard →
5

Select Brevo and enter credentials

Choose Brevo from the provider list. Enter your Brevo account login email as the username. Paste the xkeysib- SMTP key into the password field. Enter your verified FROM email address and your name or business name. SMTP host, port (587), and STARTTLS are pre-filled automatically.
Open Mail AI Dashboard →
6

Save and verify the connection

Click Save SMTP. Mail AI tests the connection instantly. A green "Custom SMTP ✓" badge appears on your linked email card when successful. Your AI replies will now be delivered from your verified Brevo sender address.
Open Mail AI Dashboard →

✅ Success looks like: After saving, your linked email card in the Mail AI dashboard shows a green "Custom SMTP ✓" badge. AI-drafted replies will now be delivered from your verified Brevo sender address, with your name in the From field.

Troubleshooting Common Brevo SMTP Errors

"Sender not verified" error

This is the most common Brevo error. It means the FROM email address you entered in Mail AI has not been verified as a sender in your Brevo account. Go to Brevo → Settings → Senders & IPs, add the exact FROM email address, and click the confirmation link in the verification email Brevo sends to that address. Then test again in Mail AI.

"Authentication failed" or "Username/Password incorrect"

Check two things: (1) your Username is your Brevo login email — not the FROM email — and (2) your Password is the xkeysib- SMTP Key, not your Brevo account password. If you cannot find your key, generate a new one at Brevo → Settings → SMTP & API — old keys are not shown again after creation.

SMTP Key is not visible / was lost

Brevo only shows the full SMTP Key once, immediately after generation. If you did not copy it, simply generate a new key — it takes 10 seconds. Go to Brevo → Settings → SMTP & API → Generate a new SMTP key, name it MailAI (you can delete the old one), and paste the new key into Mail AI.

Daily limit reached

The free Brevo plan allows 300 emails per day. If you exceed this, emails queue until midnight (CET) when the counter resets. Mail AI's own daily limit is 30 replies per account, so in practice most users will not hit Brevo's free cap. For higher volume, upgrade to a Brevo paid plan.

Brevo vs Gmail SMTP — Which Should You Use?

Feature	💚 Brevo	📧 Gmail
Custom domain email (e.g. [email protected])	✅ Yes	❌ No
Free daily sending limit	300 emails/day	500 emails/day
Requires 2-Step Verification setup	✅ No	❌ Yes (for App Password)
Open & click tracking	✅ Yes	❌ No
Transactional deliverability	✅ Excellent	Good
New account required	Yes (free)	✅ No

Rule of thumb: use 📧 Gmail if you reply from a personal @gmail.com address. Use 💚 Brevo for everything else — custom domains, business emails, or when you want delivery analytics.

Brevo Free Plan — Sending Limits Summary

Free plan: 300 emails/day, unlimited contacts, no monthly fee
Starter plan: from ~$25/month for 20,000 emails/month, no daily cap
Business plan: up to 100,000 emails/month, plus open/click analytics and A/B testing
For most small businesses using Mail AI (30 replies/day limit), the free plan is more than enough

Ready to Send?

With Brevo SMTP connected, your Mail AI workflow is complete: customer emails arrive, the AI summarises and drafts a reply, and when you click Send it leaves from your own business email address — professionally branded, fully threaded, and completely invisible to the recipient as AI-assisted.

Go to your Mail AI dashboard →