Flexmail email service provider (ESP)

According to Live Direct Marketing's daily Tranco top-1M scan (July 13, 2026), Flexmail is the email service provider (ESP) for 221 domains — 0.04% of 617,702 SPF-publishing domains. Detection method: include: mechanisms in the SPF record.

Key facts

Flexmail is an email service provider based in Belgium, offering email marketing, automation, and delivery services to smaller organisations and regional businesses. The provider operates as a managed platform for email campaigns and transactional delivery.

In email infrastructure, Flexmail's footprint concentrates in the Belgian market and SME segment rather than amongst the largest global brands. Its typical co-occurrence with Microsoft 365 indicates it serves as a specialist email-handling layer for organisations already committed to Microsoft's ecosystem. For senders and deliverability teams, this profile—regional, long-tail, complementary—means Flexmail is a secondary infrastructure consideration; understanding its authentication and SPF practices is worthwhile for specific sender segments, but not a primary focus for broad population testing.

Where Flexmail sits in the Tranco ranking

Tranco rank bandDomainsShare of its base
Top 1,00000.0%
Top 10,00010.5%
Top 100,0002913.1%
Top 1,000,00017579.2%
Unranked167.2%

Top-level domain split

TLDDomainsShare
.be12154.8%
.com4018.1%
.nl198.6%
.eu156.8%
.org62.7%
.brussels52.3%
.fr20.9%
.vlaanderen20.9%
.ch10.5%
.paris10.5%

What Flexmail users also use

Cross-tabulated from the same daily snapshot — the other email services seen on the same 221 domains.

TypeServiceDomainsShare of Flexmail users
MailboxMicrosoft 36512757.5%
MailboxUnknown / Other2210.0%
MailboxGoogle Workspace125.4%
MailboxSelf-Hosted125.4%
MailboxGeneric / unmatched (mx*.*)62.7%
MailboxSymantec MessageLabs62.7%
ESPMandrill2913.1%
ESPMailchimp2812.7%
ESPMailjet (Sinch)2611.8%
ESPSendGrid (Twilio)209.0%

SPF configuration and authentication visibility

Flexmail is discovered in email infrastructure primarily through SPF include records, where senders add Flexmail's IP authorisation blocks to their domain's SPF policy. This pattern reflects Flexmail's role as a managed delivery platform; smaller organisations using Flexmail rely on the provider's pre-built SPF includes rather than managing IP blocks directly. For senders, proper SPF configuration via Flexmail's SPF includes is essential for authentication. For recipients evaluating sender legitimacy, the presence of a Flexmail SPF include signals platform-assisted, professionally managed mail rather than self-operated infrastructure.

See the full Flexmail data page (KPI cards, trend, sample domains) →

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Frequently asked questions

Is Flexmail a significant email provider I should test deliverability against?

Flexmail is a regional European ESP concentrated in Belgium and used primarily by smaller organisations. Unless you send to a substantial proportion of Flexmail users, direct testing against it is not a primary deliverability concern; focus instead on DMARC alignment, feedback loops, and SPF/DKIM correctness, which apply across all providers.

How many domains use Flexmail?

221 domains in the Tranco top-1M use Flexmail as their email service provider (ESP) as of July 13, 2026 (0.04% of SPF-publishing domains), according to Live Direct Marketing's daily DNS scan.

Is Flexmail common enough to affect email deliverability testing?

Flexmail accounts for 0.04% of SPF-publishing domains in the top 1M. Whether you should seed a test mailbox there depends on how much of your audience it represents — the co-usage table above shows the services it appears alongside most.

Which countries or TLDs use Flexmail most?

Flexmail's largest TLD is .be (54.8% of its domains); it appears across 19 TLDs in total.

Other email service provider (ESP)s

Amazon SES (6.21%)SendGrid (Twilio) (4.76%)Mailgun (4.11%)Zendesk (3.86%)Mailchimp (3.69%)Mandrill (3.36%)HubSpot (3.18%)Salesforce (2.62%)Mailjet (Sinch) (2.13%)Cloudflare Email Routing (1.80%)