Brevo (Sendinblue) deliverability: free pre-send test

Brevo (formerly Sendinblue) is one of the easiest ESPs to adopt: friendly UI, generous free tier, and a single pipeline for email, SMS and transactional traffic. Under the hood, though, all three share the same shared-IP pools — and that is where deliverability surprises come from. The fix is simple: run a free placement test before every bulk send, and treat the result, not Brevo's own dashboard, as the source of truth.

How Brevo's sending is split

Brevo routes mail through three logical pipelines, and each one uses a different reputation profile even though the underlying infrastructure is shared:

• Transactional — account creation, receipts, password resets. Low volume, very high engagement, clean reputation.
• Marketing — newsletters, campaigns, automations. Higher volume, mixed engagement, most affected by pool neighbours.
• SMS — separate stack, irrelevant here but shares the same account-level sender score in Brevo's internal model.

Transactional traffic usually sits on a different pool from marketing, so a clean transactional history does not protect your marketing campaigns. Many users discover this the first time a newsletter drops open rate from 28% to 9% overnight — the transactional dashboard still shows 99.6% delivery, but the campaign tab tells a different story.

Shared IP pool dynamics

On Brevo's standard plans you share IPs with thousands of other senders. The pool is segmented by historical reputation, volume tier and ESP-internal risk score, but you do not see which pool you are in and you cannot request a move. In practice:

• New accounts land on a "probation" pool for 2–4 weeks. Placement here is worst, especially at Gmail and Outlook.
• Steady senders with <0.1% complaint rate graduate to a better pool. Placement improves visibly, usually in one Monday morning.
• A single bad neighbour (high-complaint campaign, blacklist hit) can drag a pool for 24–72 hours. This is not theoretical — it happens every week somewhere on the platform.

Brevo's own deliverability reports

Brevo surfaces a handful of metrics in the campaign report: Delivered, Opened, Clicked, Soft/Hard bounce, Complaint. Two are misleading if you don't know what they measure:

• Delivered — counts 250 OK from the remote SMTP. Gmail accepting a message and then dropping it into Spam counts as Delivered. Same for Outlook's Junk folder.
• Opened — requires pixel load. Gmail Image Proxy pre-fetches pixels for Promotions, so Promotions placement often shows as "opened" without the recipient ever seeing the mail.

Nothing in Brevo's dashboard tells you whether a message reached Primary, Promotions, Updates, Spam, or was blocked at envelope. That is the gap a free placement test fills.

Pre-send routine for Brevo

Five minutes before pressing Send on a bulk campaign, run this routine:

1. Create a test campaign with the same HTML, subject line, sender name and sender address you plan to use.
2. Send it to the free placement-test seed list (20+ real mailboxes across Gmail, Outlook, Yahoo, Mail.ru, Yandex, GMX, ProtonMail and more).
3. Wait 2–3 minutes for the seed mailboxes to report placement.
4. Read the per-provider result. Look at Gmail (Primary vs Promotions vs Spam), Outlook (Inbox vs Junk), Yahoo (Inbox vs Bulk), plus any CIS providers if you send to Russian-speaking audiences.
5. If Gmail Promotions > 30% or Spam > 5% on any major provider, stop and investigate before sending to the full list.

Reading per-provider results

Gmail

Primary placement on Brevo shared IPs is realistic for B2B transactional-style sends. For B2C marketing, Promotions is the norm and not a failure — Promotions opens still convert. Spam placement, however, is a red flag: it almost always points to authentication misalignment, a bad tracking domain, or pool contamination.

Outlook

Outlook's SmartScreen is strict on shared IPs. Junk folder placement on Brevo is common during the first two weeks of a new account or after any pool-reputation event. Fix: ensure your DMARC record is at least p=quarantine with domain alignment, and that the return-path aligns with your From domain.

Yahoo and AOL

Yahoo's Bulk folder is essentially its Promotions equivalent. Brevo shared IPs usually hit Yahoo Inbox fine for opt-in lists but struggle with cold or purchased data — as they should.

Mail.ru and Yandex

Brevo has weaker presence in the CIS than local players. Mail.ru in particular treats unfamiliar shared IPs as suspicious by default. If you send to Russian-speaking audiences, the per-provider breakdown will tell you whether you need a dedicated IP or a local ESP.

When to move to a dedicated IP in Brevo

Brevo offers a dedicated IP as a paid add-on. It is worth it when:

• You consistently send >40k emails per month.
• You see pool-reputation events (placement drop unrelated to your own content changes) more than once a month.
• You are a B2B sender with an engaged list and need predictable Inbox placement at Gmail and Outlook.

Below 40k/month, a dedicated IP is usually a mistake — there is not enough volume to build reputation, and a cold dedicated IP delivers worse than a warm shared pool for the first 6–8 weeks.

GlockApps comparison

GlockApps is the reference tool for inbox placement testing, and it handles Brevo traffic fine. The friction is the pricing model: per-test credits that burn fast during campaign iteration, and a starter tier that excludes most CIS providers. For a weekly newsletter on Brevo, that is 4+ tests a month; for an ecommerce automation with 10 flows, 40+.

Our free tool covers the same 20+ providers including Mail.ru and Yandex, with unlimited tests and no signup. The trade-off: we don't do advanced seed-list analytics or historical dashboards. If your use case is "check before I send," free is enough. If you need compliance-grade audit trails, GlockApps still wins.

Frequently asked questions