3.96% of sending domains use an ESP that DNS can name. Among the largest companies, 47.35%.
Which email service providers and marketing platforms send for the domains that run mail, counted by operating company and by how strongly the DNS shows it. Headline figures are active plus configured evidence; verification tokens are shown on their own. Every share here is a floor: many ESP customers leave nothing in DNS we can ask about. How the tiers work.
Sending domains, by evidence tier
Each domain counts once, at the strongest tier any of its ESPs reaches. Active and configured-only together make the headline; verified-only is never added in.
Sending domains using an ESP or marketing platform
6,447,187 of 162.8M sending domains
Source: Datazag · as of 2026-11-14
Sending domains with active ESP evidence
2,391,160 of 162.8M sending domains
Source: Datazag · as of 2026-11-14
Sending domains whose only ESP evidence is an SPF include
4,056,027 of 162.8M sending domains
Source: Datazag · as of 2026-11-14
Sending domains whose only ESP evidence is a verification token
330,421 of 162.8M sending domains
Source: Datazag · as of 2026-11-14
Share by ESP group
Sending domains: share by ESP group, active or configured
The ESP groups with the largest shares, counted by operating company. Shares add up to more than the share using any ESP, because a domain counts under every group it uses.
The largest companies against every sending domain
Each group's share of the largest companies beside its share of all sending domains, active or configured. Ranked by the companies' share. A missing bar is a share under the publication floor, not zero.
Most domains use one ESP group, many use more
A domain counts under every group its DNS names, so the group shares above add up to more than the share using any ESP. Groups, not brands: two brands one company owns count once.
ESP-using domains with one ESP group
5,698,486 of 6.4M sending domains using an ESP
Source: Datazag · as of 2026-11-14
ESP-using domains with two ESP groups
612,858 of 6.4M sending domains using an ESP
Source: Datazag · as of 2026-11-14
ESP-using domains with three or more ESP groups
135,843 of 6.4M sending domains using an ESP
Source: Datazag · as of 2026-11-14
The largest companies
The largest listed companies by employees, two thousand of them, counted per company across all the domains mapped to it. Aggregates only: no company is named or ranked.
Largest companies using an ESP or marketing platform
947 of 2,000 companies in the largest-employer sample
Source: Datazag · as of 2026-11-14
Largest companies with active ESP evidence
785 of 2,000 companies in the largest-employer sample
Source: Datazag · as of 2026-11-14
ESP-using large companies with two or more ESP groups
577 of 947 sample companies using an ESP
Source: Datazag · as of 2026-11-14
What the shares are measured over
The sending base every corpus share uses, the hosting relays counted apart from ESPs, and how many ESP groups the evidence reaches.
Sending domains: registered, not parked, with an MX that can take mail
registered domains that run mail
Source: Datazag · as of 2026-11-14
Sending domains whose SPF includes a hosting relay
2,460,068 of 162.8M sending domains
Source: Datazag · as of 2026-11-14
ESP operating groups seen on at least one domain
operating groups in the Datazag ESP catalog
Source: Datazag · as of 2026-11-14
Over time
ESP evidence has been measured daily only since November 2026. A trend appears here once there is enough history for a movement to be more than the evidence being re-checked; until then, each figure carries the date it was measured and its change since the previous measurement.
Research using this data
Microsoft and Google run the mailboxes for 24% of corporate domains, eleven times the share behind a security gateway
The gateway market is concentrated but small; the mailbox layer behind it is eleven times larger. National markets turn global shares inside out: one vendor holds almost all of Sweden's.
Read on datazag.com1 in 4 domains publish DMARC, and about half of those enforce it
A census of resolving, unparked domains: about half of DMARC publishers only report spoofing. Among domains that run mail, report-only outnumbers enforcement two to one.
Read on datazag.comWho Really Runs Business Email? Microsoft leads Google 9 : 1 at the largest companies, and is level with it across corporate mail
The keyhole effect: enterprise studies see the largest companies. Across all corporate mail domains, hosting companies and registrars run more mail than Microsoft and Google together.
Read on datazag.comQuery these statistics directly
Every figure on this page is served as Parquet. Same format as the corpus itself.
SELECT * FROM read_parquet('https://observatory.datazag.com/observatory_statistics.parquet');