Useinbox email service provider (ESP)

According to Live Direct Marketing's daily Tranco top-1M scan (July 13, 2026), Useinbox is the email service provider (ESP) for 82 domains — 0.01% of 617,702 SPF-publishing domains. Detection method: include: mechanisms in the SPF record.

Key facts

Useinbox is an email service provider that organisations use to manage and send email campaigns and transactional messages. It appears across the Tranco top-1M dataset as an SPF-authorised sender, marking its established role in email infrastructure for its customer base.

Useinbox's footprint concentrates in the long tail of smaller and mid-market sites rather than the internet's largest brands, and clusters heavily within the .com namespace. It is most commonly paired with Google Workspace deployments. This pattern indicates to mail administrators and filtering systems that Useinbox traffic originates predominantly from smaller-scale senders, a distinction that should inform reputation assessment and delivery evaluation for organisations receiving or filtering email from Useinbox-authorised sources.

Where Useinbox sits in the Tranco ranking

Tranco rank bandDomainsShare of its base
Top 1,00000.0%
Top 10,00000.0%
Top 100,00089.8%
Top 1,000,0006579.3%
Unranked911.0%

Top-level domain split

TLDDomainsShare
.com4352.4%
.tr1417.1%
.com.tr1315.9%
.org78.5%
.net44.9%
.ke11.2%

What Useinbox users also use

Cross-tabulated from the same daily snapshot — the other email services seen on the same 82 domains.

TypeServiceDomainsShare of Useinbox users
MailboxGoogle Workspace2834.1%
MailboxSelf-Hosted1417.1%
MailboxMicrosoft 3651315.9%
MailboxUnknown / Other911.0%
MailboxYandex 36056.1%
MailboxGeneric / unmatched (mx*.*)33.7%
ESPAmazon SES67.3%
ESPMailerSend44.9%
ESPSendGrid (Twilio)33.7%
ESPElastic Email33.7%

SPF authentication and the Useinbox SMB footprint

Useinbox's presence in a domain's SPF record indicates that organisation has authorised Useinbox as a sending channel. Receiving mail systems and spam filters encounter Useinbox predominantly as a small-to-mid-market sender rather than as an enterprise or high-volume publisher. This SMB-weighted footprint means filtering and reputation algorithms should calibrate their assessment of Useinbox traffic—and domains authorising it—according to actual deployment: typically smaller, Google Workspace-backed organisations with sending volumes and compliance patterns characteristic of that segment.

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

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Frequently asked questions

What is Useinbox, and why would I see it in an SPF record?

Useinbox is an email service provider that organisations use to send email on their behalf; its SPF record presence means that domain has authorised Useinbox as a legitimate sender. Useinbox is most prevalent among smaller and mid-sized businesses, particularly those using Google Workspace, so filtering and reputation decisions should reflect that distribution.

How many domains use Useinbox?

82 domains in the Tranco top-1M use Useinbox as their email service provider (ESP) as of July 13, 2026 (0.01% of SPF-publishing domains), according to Live Direct Marketing's daily DNS scan.

Is Useinbox common enough to affect email deliverability testing?

Useinbox accounts for 0.01% 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 Useinbox most?

Useinbox's largest TLD is .com (52.4% of its domains); it appears across 6 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%)