Flowmailer email service provider (ESP)

According to Live Direct Marketing's daily Tranco top-1M scan (July 13, 2026), Flowmailer is the email service provider (ESP) for 679 domains — 0.11% of 617,702 SPF-publishing domains. Detection method: include: mechanisms in the SPF record.

Key facts

Flowmailer is a Dutch email service provider that manages transactional and marketing mail delivery for its customers. Operated from the Netherlands, it serves organisations across Northern Europe with a focus on regional data residency and compliance.

In global mail infrastructure, Flowmailer appears as an SPF include on smaller and mid-market websites rather than major enterprise brands, with notable concentration in the .nl domain space. It frequently co-occurs with Microsoft 365 in organisations that deploy segmented mail handling, where Flowmailer manages specific mail flows whilst a primary platform handles general corporate traffic. This pattern reflects its role as a supplementary provider rather than a primary platform.

Where Flowmailer sits in the Tranco ranking

Tranco rank bandDomainsShare of its base
Top 1,00010.1%
Top 10,000111.6%
Top 100,0009013.3%
Top 1,000,00053278.4%
Unranked456.6%

Top-level domain split

TLDDomainsShare
.nl30745.2%
.com15623.0%
.se426.2%
.de395.7%
.be334.9%
.no172.5%
.eu121.8%
.net101.5%
.io91.3%
.co.uk71.0%

What Flowmailer users also use

Cross-tabulated from the same daily snapshot — the other email services seen on the same 679 domains.

TypeServiceDomainsShare of Flowmailer users
MailboxMicrosoft 36537154.6%
MailboxGoogle Workspace11416.8%
MailboxUnknown / Other7210.6%
MailboxSelf-Hosted294.3%
MailboxGeneric / unmatched (mx*.*)182.7%
MailboxMimecast111.6%
ESPMandrill9714.3%
ESPSendGrid (Twilio)8412.4%
ESPZendesk7811.5%
ESPMailjet (Sinch)6810.0%

Flowmailer in Microsoft 365 hybrid configurations

Organisations that combine Flowmailer with Microsoft 365 typically isolate transactional, compliance-critical, or high-volume mail on Flowmailer's region-hosted infrastructure whilst routing general corporate mail through their primary platform. This segmentation appeals to European entities where data residency, audit trail isolation, or mail load balancing justifies multiple outbound providers. When both providers appear in an organisation's SPF record, each must authenticate correctly for delivery to succeed, and mail routing must be properly configured to match SPF claims.

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

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Frequently asked questions

Do I need to test or whitelist Flowmailer for email deliverability?

Only if your organisation sends mail via Flowmailer—verify your outbound mail routing and SPF configuration. If Flowmailer appears in inbound mail you receive, the sender is responsible for configuring it correctly.

How many domains use Flowmailer?

679 domains in the Tranco top-1M use Flowmailer as their email service provider (ESP) as of July 13, 2026 (0.11% of SPF-publishing domains), according to Live Direct Marketing's daily DNS scan.

Is Flowmailer common enough to affect email deliverability testing?

Flowmailer accounts for 0.11% 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 Flowmailer most?

Flowmailer's largest TLD is .nl (45.2% of its domains); it appears across 32 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%)