Customer.io — market share 2026

esp

According to Live Direct Marketing's daily Tranco top-1M scan (July 13, 2026), Customer.io is the email service provider (ESP) for 458 domains — 0.07% of 617,702 SPF-publishing domains. Its strongest TLD is .com (67.5% of its domains). Detection: include: mechanisms in the SPF record.

458domains

0.07%of SPF-publishing domains

49distinct TLDs

2026-07-13snapshot (updated daily)

Commonly used together with Customer.io

What else the same 458 domains use — cross-tabulated from the same daily snapshot (2026-07-13).

Type	Service	Domains	Share of Customer.io users
Mailbox	Google Workspace	355	77.5%
Mailbox	Microsoft 365	35	7.6%
Mailbox	Unknown / Other	13	2.8%
Mailbox	Self-Hosted	12	2.6%
Mailbox	Generic / unmatched (mail.*)	10	2.2%
Mailbox	Generic / unmatched (mx.)	6	1.3%
ESP	Zendesk	105	22.9%
ESP	Mandrill	74	16.2%
ESP	SendGrid (Twilio)	71	15.5%
ESP	Mailgun	67	14.6%

TLD distribution (top 30 of 49)

com — 309 (67.5%)

io — 25 (5.5%)

casino — 10 (2.2%)

co — 10 (2.2%)

net — 9 (2.0%)

org — 8 (1.7%)

com.br — 6 (1.3%)

de — 6 (1.3%)

co.uk — 6 (1.3%)

nl — 5 (1.1%)

ai — 5 (1.1%)

no — 5 (1.1%)

ch — 4 (0.9%)

it — 3 (0.7%)

eu — 3 (0.7%)

fr — 3 (0.7%)

in — 3 (0.7%)

com.au — 3 (0.7%)

me — 2 (0.4%)

ly — 2 (0.4%)

co.nz — 2 (0.4%)

es — 2 (0.4%)

trade — 1 (0.2%)

edu — 1 (0.2%)

love — 1 (0.2%)

com.ar — 1 (0.2%)

biz — 1 (0.2%)

dk — 1 (0.2%)

sh — 1 (0.2%)

cloud — 1 (0.2%)

Frequently asked questions

How many domains use Customer.io?

458 domains in the Tranco top-1M use Customer.io as their email service provider (ESP) as of July 13, 2026, according to Live Direct Marketing's daily DNS scan.

What is Customer.io's market share?

Customer.io holds 0.07% of SPF-publishing domains in the Tranco top-1M (snapshot of 2026-07-13). The number is recomputed every day.

What are the biggest alternatives to Customer.io?

The largest email service provider (ESP)s in the same category by Tranco top-1M share are: Amazon SES, SendGrid (Twilio), Mailgun, Zendesk, Mailchimp (as of 2026-07-13).

Largest email service provider (ESP)s in this category

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%)

ESP / mailing services portfolio → · Full daily report →

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Domain sample (top 100 by Tranco rank)

statuspage.io mapbox.com yotpo.com guard.io jivosite.com codecademy.com viki.com justanswer.com zonaprop.com.ar ifttt.com tryfi.comrapidapi.comhostgator.inlist.lywanderlog.comlivestorm.coinsurancejournal.comgobranded.comsurfline.comthebump.com123formbuilder.comtodesktop.combigrock.inaplus.netsmiirl.comwisestamp.comstorj.iotheorg.comkeywordtool.iopurechat.comnuuvem.comprezly.comretool.comuppromote.comcludo.commixmax.comtrustpilot.nethunter.ioreadcube.comloyaltylion.comstickermule.commatific.comdeepdyve.comcareem.comlogrocket.comstoryblocks.comab-in-den-urlaub.depopupsmart.comlensa.cominboxsdk.comwoopra.comdealroom.cogrowkudos.combiorender.comflowplayer.organytrack.iobrainscape.compillpack.comkpler.comcurrent.usnotionpress.combitstarz.cominfluence.costackshare.iosportsbet.iomaxbet.rscxl.comcl.lypacermonitor.commachighway.comclearvoice.comdoublegood.comdesignhill.commeilleursagents.come-file.comscienceofpeople.comsoftswiss.netpublicgood.com20bet.comspeisekarte.dex-plane.comdlvr.itgooverseas.comstreak.comgorgias.ioresellerclub.comsbmt.iofirebase.comelocal.comzavamed.comfoursixty.combettingexpert.comrbnett.noseguno.combitcasino.iopippa.iowhoppah.compollfish.comleadboxer.commomento360.com

Showing 100 of 458 domains.