Brevo Warm Up: How to Warm Up Brevo SMTP Sending

To warm up Brevo SMTP sending, connect Brevo as the SMTP relay and your real mailbox as the IMAP inbox, then ramp from 3 to 30 warm-up emails per day. If you skip the inbox, DNS, or volume ramp, replies and spam rescues cannot work. This guide gives the exact connection route, records, schedule, and checks.

Brevo SMTP relay is only the sending side. Your setup still needs a mailbox that can receive warm-up mail, collect replies, and let the engine move warm-up messages out of Spam. In the free warm-up tool, use Other IMAP + SMTP: Brevo for SMTP, and your real mailbox for IMAP.

That is different from warming a normal mailbox provider. With Gmail, Zoho, iCloud, Yahoo, Lark, or cPanel mail, the same provider often handles both IMAP and SMTP. With Brevo, the relay sends, but your actual inbox receives.

Use this setup only when Brevo is authorised to send for the same From address or domain you are warming. If Brevo is not authenticated for that sender, receiving providers can treat the mail as misaligned or suspicious.

What Brevo settings do you need?

Use Brevo SMTP for sending and a real mailbox for receiving. BobWork connects this through Other IMAP + SMTP because Brevo does not provide the receiving inbox in this setup.

Check Brevo’s own SMTP screen before you paste credentials. Confirm three things: the SMTP login, the generated SMTP key, and whether Brevo has permission to send from the address you enter.

A warm-up engine needs both sides. It sends plain office-style messages through Brevo. Other warm-up inboxes receive those messages, reply to some of them, and rescue only warm-up mail that lands in Spam.

In BobWork, warm-up mail is identified by the engine’s own hidden header. Real mail is never read, moved, or answered. Warm-up mail found in Spam is moved to Inbox, marked read, labelled Warm-up, and archived after 24 hours.

The free pool does this automatically. BobWork uses a shared warm-up network by default, or a private pool per account if you prefer. One mailbox is enough to start in the shared network. A private pool needs at least two mailboxes.

What do providers check?

Brevo is the SMTP relay, but inbox placement is decided by receiving providers. Google, Yahoo, Microsoft, business filters, and private gateways check signals around your domain, sender identity, content, volume, and recipient behaviour.

For a Brevo SMTP setup, keep these signals clean.

Complaint thresholds vary by provider. Google recommends keeping spam complaints under 0.1% and avoiding 0.3% or higher. Yahoo requires senders to stay under 0.3%. Treat those numbers as ceilings, not goals.

Warm-up cannot fix bad targeting, purchased lists, or an offer people do not want. It can help create normal mailbox behaviour before you add real outreach. For the broader mechanics, read how warm-up signals work.

How do you connect Brevo?

Use the Other IMAP + SMTP preset. Do not connect Brevo as if it were a mailbox provider. Brevo is the relay; your inbox remains with Gmail, Zoho, iCloud, Yahoo, Fastmail, cPanel, Hostinger, Namecheap, Titan, or another IMAP provider.

Before you start, open Brevo and create or copy your SMTP key. Also confirm your SMTP login. Brevo may show your account email or a specific SMTP login such as an ID-based address.

Step 1: Prepare the inbox

Choose the real mailbox you want to warm. It must receive mail through IMAP. It should be the same visible sender identity you plan to use, or part of the same authorised sending setup.

Find its IMAP host, port, and security mode in your mailbox provider. If the mailbox uses two-factor authentication, you may need an app password or mail-client password instead of the normal password.

If you are warming a mailbox hosted elsewhere, use the matching provider guide. For example, see Google Workspace warm-up, Zoho Mail warm-up, or iCloud Mail warm-up.

Step 2: Enter Brevo SMTP

In BobWork, choose Other IMAP + SMTP. Enter your mailbox details in the IMAP section. Then enter Brevo in the SMTP section.

Use smtp-relay.brevo.com as the SMTP host. Start with port 587 and STARTTLS. If your network or server requires SSL from the beginning, use port 465 with SSL.

Use the Brevo SMTP key as the password. Do not use the Brevo API key. They are different credentials.

For the username, use the account email or the SMTP login shown inside Brevo. If Brevo displays an ID-style SMTP login, use that exact value.

Step 3: Send a test

Save the mailbox and send the connection test. A valid setup proves two things: BobWork can log in to your receiving inbox through IMAP, and Brevo accepts the SMTP send.

If SMTP passes but IMAP fails, warm-up is not ready. Replies and spam rescue need the receiving mailbox.

If IMAP passes but SMTP fails, check the Brevo SMTP key, login value, port, and TLS mode. Most Brevo connection issues come from using the API key, the wrong username, or the wrong port-security pair.

You can read the exact engine behaviour, including daily ramp, reply rate, thread length, and timing, in the warm-up strategy.

Which DNS records matter?

Do DNS before volume. SPF, DKIM, and DMARC do not guarantee inbox placement, but missing authentication is one of the fastest ways to look untrusted.

Use Brevo’s current domain authentication screen or DNS help for the exact values. Do not copy records from a blog post and assume they apply to your account. Providers can change hostnames, selectors, and verification values.

SPF has one common trap. A domain should publish one SPF TXT record. If you already send mail through Google Workspace, Zoho, your website, or another tool, merge each approved sender into the same SPF record.

DKIM has a different trap. The selector matters. If Brevo gives you a selector, use that exact selector when checking the record. A DKIM check against the wrong selector can fail even when the correct record exists.

DMARC ties the setup together. Start with p=none while proving the setup. This lets you collect alignment results without asking receiving providers to quarantine or reject mail.

For primary setup instructions, use Brevo’s documentation for SMTP sending and domain authentication. For the standard behind DMARC, see RFC 7489.

What ramp should you use?

Start low even if Brevo allows more. Warm-up is about building consistent, low-risk behaviour before you ask the mailbox to carry real outbound volume.

BobWork starts at 3 warm-up emails per day, adds 2 per day, and caps at 30 per day by default. The cap is editable per mailbox up to 100, but you should not raise it early on a new Brevo sending setup.

Weekends run at 30% of the normal daily target in BobWork. Sends are spread between 09:00 and 18:00 in the mailbox’s own time zone, with randomness. A pair of mailboxes never writes to each other twice within 3 hours.

About 40% of received warm-up mail gets a reply, and threads end after 3 messages. The content is plain text office talk, with no links or images.

If you want a custom calendar, use the email warm-up schedule generator. For a new domain, use a longer plan from the new-domain warm-up guide.

During active campaigns, keep warm-up at 10–15 per day. For real outreach, a typical safe range is no more than 30–50 cold emails per day per mailbox. Add mailboxes instead of forcing one mailbox to send too much.

How do you fix errors?

Most Brevo warm-up failures are setup errors, not deliverability problems. Fix the connection first, then judge placement.

Do not troubleshoot deliverability while the connection is half-working. A Brevo SMTP success is not enough. The IMAP inbox must also be readable, because warm-up depends on received mail, replies, and spam-folder checks.

If Brevo blocks or throttles sends, check Brevo’s current limits and account status. Do not bypass a provider block by switching relays and keeping the same list behaviour. The same bad signals will follow you.

Avoid using Postmark as a cold-email replacement. Postmark requires permission-based lists and prohibits purchased or rented lists. If your use case is cold outreach, read Postmark’s terms before sending through it.

What should you do now?

Work through this list before you start real outreach. It is faster than guessing after messages land in Spam.

BobWork marks a mailbox ready for outbound when it has warmed for at least 7 days, has a 7-day spam rate of 3% or lower, and has received at least 30 warm-up emails. That is a gate, not a promise of inbox placement.

If the mailbox is new, wait longer. A new domain usually needs 2–3 weeks before meaningful outreach. Keep authentication passing and avoid sudden jumps.

Once Brevo SMTP is connected, DNS passes, and warm-up looks stable, send your first real campaign in small batches. Keep the message plain. Avoid link-heavy copy. Use a real reply-to mailbox, and stop contacting anyone who replies, unsubscribes, or bounces.

BobWork Email Warm-up is free, with no credit card and no time limit, for up to 10 mailboxes on new accounts. It supports Brevo-style relay setups through Other IMAP + SMTP: Brevo sends, and your real inbox receives. Connect one mailbox, run the ramp, and add outreach only after the ready checks pass.

Frequently asked questions