Flexmail email service provider (ESP)
According to Live Direct Marketing's daily Tranco top-1M scan (September 16, 2026), Flexmail is the email service provider (ESP) for 234 domains — 0.04% of 634,905 SPF-publishing domains. Detection method: include: mechanisms in the SPF record.
Key facts
- 234 domains in the Tranco top-1M use Flexmail (0.04% of SPF-publishing domains).
- Snapshot date: 2026-09-16 — recomputed every day.
- Strongest TLD: .be (56.4% of its domains).
- Most co-used service: Microsoft 365.
- Directory category: email service provider.
Why Flexmail appears in this category
Flexmail — Belgian email marketing.
We classify it as a email service provider from include: mechanisms in the SPF record matching a maintained provider rule. This is infrastructure attribution from public DNS, not evidence of a direct contract or exclusive use.
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 band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 0 | 0.0% |
| Top 10,000 | 1 | 0.4% |
| Top 100,000 | 28 | 12.0% |
| Top 1,000,000 | 201 | 85.9% |
| Unranked | 4 | 1.7% |
Top-level domain split
| TLD | Domains | Share | |
|---|---|---|---|
| .be | 132 | 56.4% | |
| .com | 39 | 16.7% | |
| .nl | 21 | 9.0% | |
| .eu | 16 | 6.8% | |
| .org | 6 | 2.6% | |
| .brussels | 5 | 2.1% | |
| .de | 3 | 1.3% | |
| .vlaanderen | 2 | 0.9% | |
| .lu | 1 | 0.4% | |
| .paris | 1 | 0.4% |
What Flexmail users also use
Cross-tabulated from the same daily snapshot — the other email services seen on the same 234 domains.
| Type | Service | Domains | Share of Flexmail users |
|---|---|---|---|
| Mailbox | Microsoft 365 | 144 | 61.5% |
| Mailbox | Unknown / Other | 17 | 7.3% |
| Mailbox | Google Workspace | 12 | 5.1% |
| Mailbox | Self-Hosted | 11 | 4.7% |
| Mailbox | Proofpoint | 7 | 3.0% |
| Mailbox | Barracuda | 6 | 2.6% |
| ESP | Mandrill | 32 | 13.7% |
| ESP | Mailchimp | 30 | 12.8% |
| ESP | Mailjet (Sinch) | 26 | 11.1% |
| ESP | SendGrid (Twilio) | 21 | 9.0% |
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) →
Run a free inbox-placement test across Gmail, Outlook, Yahoo and more — see exactly where your mail lands and why.
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?
234 domains in the Tranco top-1M use Flexmail as their email service provider (ESP) as of September 16, 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 (56.4% of its domains); it appears across 18 TLDs in total.