---
title: "Email Provider Market Share 2026: Who Sends the Mail"
description: "Microsoft 365 = 19.6%, Google Workspace = 13.6% of 3.08M SPF-enabled domains (DMARCguard scan, Mar 2026). The 2026 email provider market share, sourced."
publishedAt: 2026-07-02
tags: ["email-provider-market-share", "spf", "microsoft-365", "google-workspace", "transactional-email", "email-authentication", "research"]
faq:
- question: "What is the most popular email service provider?"
answer: "By sending share, Microsoft 365 is the most-used email provider: 603,854 SPF-enabled domains (19.6%) authorize it, ahead of Google Workspace (13.6%), in a 5.5M-domain Tranco scan (DMARCguard, 2026-03-15). By raw accounts, Gmail leads with about 1.8 billion users (SellCell, May 2026) — a different measure."
- question: "What is the market share of Microsoft 365 in email?"
answer: "Microsoft 365 holds 19.6% of SPF-enabled domains (603,854 of 3,077,219) on the sending axis (DMARCguard, 2026-03-15). 6sense's email-management category independently puts it at 19.97% — within 0.4 points — though it counts company installs, not domains."
- question: "What is Google Workspace's email market share?"
answer: "Google Workspace is authorized by 13.6% of SPF-enabled domains (419,733), second behind Microsoft 365 (DMARCguard, 2026-03-15). It leads the highest-traffic Tranco tiers (top-1k through top-100k) while Microsoft 365 leads the long tail."
- question: "Who are the top 10 email providers by sending share?"
answer: "Microsoft 365 (19.6%), Google Workspace (13.6%), GoDaddy (6.6%), websitewelcome.com (2.5%), Amazon SES (2.5%), SendGrid (2.3%), Mailgun (2.2%), relay.mailchannels.net (2.2%), Mailchimp (1.9%), and Namecheap (1.7%) of SPF-enabled domains (DMARCguard, 2026-03-15)."
- question: "What is the most used email service in the world?"
answer: "It depends on the measure. By accounts, Gmail (about 1.8 billion users, SellCell May 2026). By opens, Apple Mail and Gmail are about 90% (Litmus, Feb 2026). By business sending infrastructure, Microsoft 365 leads at 19.6% of SPF-enabled domains (DMARCguard, 2026-03-15). Three measures, three answers."
- question: "Is Microsoft 365 bigger than Google Workspace?"
answer: "By email-sending share, yes — Microsoft 365 (19.6%) leads Google Workspace (13.6%) of SPF-enabled domains (DMARCguard, 2026-03-15). By collaborative-applications revenue, Microsoft also leads (IDC: 30.1% vs 14.7%, 2023 data year). By detected company count, technographic trackers often show Google ahead."
---
# Who Sends the Internet's Email? The 2026 Provider Market Share
**Microsoft 365 sends for 19.6% of SPF-enabled domains; Google Workspace for
13.6%.** That is the 2026 email provider market share on the one axis almost no
chart measures — _who actually sends the mail_.
Most "email provider market share" and "email service provider market share"
rankings measure something else: who people _read_ mail in, who _hosts_ the
mailbox, or how many _accounts_ exist. Five different datasets give five
different answers about the biggest email provider because they count five
different things. This post adds the missing axis, declared sending
infrastructure, from [our 5.5M-domain SPF supply-chain study](/research/spf-supply-chain/),
which parsed live SPF `include:` directives across the full Tranco list and
ships with a downloadable CSV and JSON.
What you get: a ranked provider table by send-share, a methodology table that
reconciles why the numbers disagree, and a transactional-ESP breakout. Every
figure is dated, every figure sourced.
## Email provider market share, 2026 — the SPF-include view
Across 3,077,219 SPF-enabled domains in a 5,499,028-domain Tranco scan
(DMARCguard, 2026-03-15), the five most-used sending providers account for 44.8%
of all SPF `include:` directives: Microsoft 365 (19.6%), Google Workspace
(13.6%), GoDaddy (6.6%), websitewelcome.com (2.5%), and Amazon SES (2.5%). Every
percentage below is a share of those 3,077,219 SPF-enabled domains, mapped by
their `include:` or `redirect=` directive. Each `include:` directive told us one
thing: this domain has authorized that provider to send email on its behalf. A
domain whose SPF record includes
[`spf.protection.outlook.com`](/learn/spf/) is declaring Microsoft as a sender.
That is the axis this post measures — "send-share" — and it is _not_ opens,
_not_ mailbox hosting, _not_ user accounts. SPF (RFC 7208) is, at internet
scale, a delegation protocol: most domains do not send from their own
infrastructure; they delegate to providers via `include:`.
The top-5 figure is a transparent sum of the first five provider rows
(19.6 + 13.6 + 6.6 + 2.5 + 2.5 = 44.8%). Below it, the ranking spreads across
hundreds of providers — from mailbox hosts to specialized transactional
services.
| # | Provider | Category | Domains | % of SPF |
| --- | ---------------------------------- | ------------- | ------: | -------: |
| 1 | Microsoft 365 | email-hosting | 603,854 | 19.6% |
| 2 | Google Workspace | email-hosting | 419,733 | 13.6% |
| 3 | GoDaddy | other | 204,621 | 6.6% |
| 4 | websitewelcome.com | other | 76,405 | 2.5% |
| 5 | Amazon SES | transactional | 75,817 | 2.5% |
| 6 | SendGrid | transactional | 71,169 | 2.3% |
| 7 | Mailgun | transactional | 68,562 | 2.2% |
| 8 | relay.mailchannels.net | other | 67,831 | 2.2% |
| 9 | Mailchimp | marketing | 58,736 | 1.9% |
| 10 | Namecheap | other | 51,704 | 1.7% |
| 11 | Mailchimp Transactional (Mandrill) | transactional | 49,568 | 1.6% |
| 12 | Zoho Mail | email-hosting | 49,361 | 1.6% |
| 13 | HubSpot | crm | 49,015 | 1.6% |
## Microsoft 365 market share — 19.6% of SPF-enabled domains
Microsoft 365 is the most-used email-sending provider on the public web: 603,854
SPF-enabled domains (19.6%) authorize it via `spf.protection.outlook.com`, more
than any other provider in a 5,499,028-domain Tranco scan (DMARCguard,
2026-03-15). The include domain `spf.protection.outlook.com` itself appears in
598,643 records (19.5%) — the single most-referenced SPF include on the
internet.
The mechanics are direct: when a domain's SPF record carries
`include:spf.protection.outlook.com`, it authorizes Microsoft to send mail in
that domain's name and inherits every IP range Microsoft publishes. Suffix-
mapping that include to a named provider is how we get from "a DNS string" to
"this domain authorizes Microsoft 365 to send."
How does that compare to the other ways people measure Microsoft 365? Each
answers a different question, against a different denominator:
- **Installs (closest cross-check):**
[6sense's email-management category](https://6sense.com/tech/email-management/microsoft-office-365-market-share)
puts Microsoft Office 365 at 19.97%, within 0.4 points of our 19.6% and the
strongest external echo we found, but it counts _company installs_, not
domains (2026 data). 6sense's hosted-email cut puts Microsoft Exchange Online
near 39%, roughly double, purely because the category denominator changes.
- **Revenue / seats:**
[Gartner](https://www.gartner.com/en/documents/6860166) pegs Microsoft 365 at
roughly 77% of SaaS enterprise productivity, a revenue-and-seat axis, not a
domain axis.
- **Self-reported seats:** Microsoft discloses over 450 million paid commercial
seats (FY26 Q2, quarter ended Dec 31, 2025).
Four numbers (19.6%, 19.97%, ~39%, ~77%) come from four denominators answering
four questions. The 19.6% is the only one that measures declared _sending_
infrastructure.
## Google Workspace market share — 13.6% of SPF-enabled domains
Google Workspace is the second-most-used sending provider: 419,733 SPF-enabled
domains (13.6%) authorize it via `_spf.google.com`, in a 5,499,028-domain Tranco
scan (DMARCguard, 2026-03-15). The include domain `_spf.google.com` appears in
415,155 records (13.5%).
Where Google Workspace lands shifts by domain rank. In our tier breakdown,
Google Workspace is the **top** provider in the top-1k, top-10k, and top-100k
Tranco tiers, the highest-traffic domains on the internet, while Microsoft 365
leads the top-1M tier and the long tail beyond it. The crossover sits between
the top-100k and top-1M. That pattern _resembles_ the analyst enterprise-vs-SMB
split (Microsoft strong in enterprise and regulated buyers; Google strong in
SMB and education): roughly half of Google Workspace organizations have fewer
than 10 employees (6sense, 2026). But treat that as an external split that helps
**explain, not confirm**, our tier finding — they measure different things.
For contrast on a different denominator,
[W3Techs](https://w3techs.com/technologies/overview/email_server) fingerprints
website mail infrastructure and puts Gmail at 17.2% and Microsoft at 13.5% of
the top ~10M websites (May 2026), close to our numbers by coincidence of
denominator, not by measuring the same thing. By self-reported accounts, Google
cites more than 3 billion users and over 11 million paying customers (Dec 2025).
If you authorize Google to send for your domain, our
[DMARC setup for Google Workspace](/blog/dmarc-google-workspace-setup/)
walkthrough covers the full record and rollout.
## Google Workspace vs Microsoft 365 market share — head-to-head by send-share
On the sending axis, Microsoft 365 leads Google Workspace 19.6% to 13.6% of
SPF-enabled domains — a 6-point gap. But the lead flips by tier: Google
Workspace tops the highest-traffic domains while Microsoft 365 dominates the
long tail (DMARCguard, 2026-03-15).
The bigger point is that "who is bigger" has no single answer. It depends on
what you count, and the lead reverses across axes:
- **Send-share (this study):** Microsoft 365 19.6% vs Google Workspace 13.6% of
SPF-enabled domains.
- **Collaborative-applications revenue (IDC, 2023 data year):** Microsoft 30.1%
vs Google 14.7%.
- **Office-suites company count (6sense, 2026):** Google Workspace 77.37% vs
"Microsoft Office" 11.90% — but flag the artifact: 6sense splits Microsoft
across separate "Microsoft 365," "Microsoft Office," and "Office 365 E3"
entries, deflating its apparent share in that one cut.
These are non-substitutable axes, not contradictions to reconcile into one
number. The lead flips depending on what you count, which is exactly why a
single "email provider market share" figure misleads.
## Why the numbers disagree — opens vs MX vs installs vs users vs sends
Five datasets give five different "market share" answers for the same providers
because each measures a different layer of the email stack: where mail is _read_
(opens), where the mailbox is _hosted_ (MX/server fingerprint), what companies
_install_ (tech-graph), how many _accounts_ exist (surveys), and, uniquely here,
what infrastructure domains _declare for sending_ (SPF includes).
Walk the five axes, one labeled stat each:
- **Opens:** [Litmus](https://www.litmus.com/email-client-market-share) gives
Apple about 52% and Gmail about 27% of email opens (Feb 2026, 1.1B+ opens).
Pair it with the caveat: Litmus states "over 50% of email opens happen on a
device with Apple's Mail Privacy Protection activated," which auto-prefetches
tracking pixels and inflates Apple's apparent share.
- **Server / MX:**
[W3Techs](https://w3techs.com/technologies/overview/email_server) gives Gmail
17.2% and Microsoft 13.5% of the top ~10M websites (May 2026).
- **Installs:** 6sense puts Microsoft 365 at 19.97% in its email-management
category but near 39% in its hosted-email category, same vendor, different
category, roughly a 2× swing (2026).
- **Accounts / surveys:** SellCell estimates Gmail at about 1.8 billion users
(May 2026); Statista's Consumer Insights chart reports Gmail used by about 75%
of US respondents (respondents, not accounts).
- **Sends (ours):** Microsoft 365 19.6% and Google Workspace 13.6% of
SPF-enabled domains (DMARCguard, 2026-03-15).
There is a gap none of them fills:
[Cloudflare Radar](https://radar.cloudflare.com/year-in-review/2025) measures
authentication pass-rates and threat share (more than 5% of analyzed email was
malicious in 2025) — not per-provider send-share. No network-telemetry source
publishes a clean share of mail _sent_ per provider. That absence is exactly
what the SPF-include axis fills.
The same axes, side by side:
| Axis / source | What it counts | Headline 2026 number | Denominator |
| -------------------------------------- | -------------------------------------------------- | ------------------------------------------------- | ---------------------------------------------------------- |
| **Sends — DMARCguard (this study)** | SPF `include:` directives (declared sending infra) | Microsoft 365 19.6%, Google Workspace 13.6% | 3,077,219 SPF-enabled domains (of 5.5M Tranco), 2026-03-15 |
| Opens — Litmus | Email opens (tracking pixel) | Apple ~52%, Gmail ~27% | 1.1B+ opens, Feb 2026 (Apple MPP-inflated) |
| Server/MX — W3Techs | Mail-server fingerprint of websites | Gmail 17.2%, Microsoft 13.5% | Top ~10M websites, May 2026 |
| Installs — 6sense | Detected company installs | Microsoft 365 19.97% (email-mgmt) / ~39% (hosted) | Tracked companies (category-dependent), 2026 |
| Accounts/surveys — SellCell / Statista | User accounts / self-reported usage | Gmail ~1.8B users / ~75% US respondents | Global accounts (estimated) / US survey, 2026 |
| Telemetry — Cloudflare Radar | Auth pass-rates + threat share | No per-provider send-share published | Messages at Cloudflare, 2025 |
This is the differentiator: it is the only view on the SERP that explains _why_
five sources disagree by up to 5× on Gmail: each answers a different
question.
## Transactional ESPs ranked — Amazon SES, SendGrid, Mailgun, Mailchimp
By SPF-include send-share, the top transactional and marketing senders are
Amazon SES (2.5%), SendGrid (2.3%), Mailgun (2.2%), Mailchimp (1.9%), and
Mailchimp Transactional / Mandrill (1.6%) of SPF-enabled domains (DMARCguard,
2026-03-15).
Every count traces to the provider ranking: Amazon SES 75,817; SendGrid 71,169;
Mailgun 68,562; Mailchimp 58,736; Mailchimp Transactional 49,568; Zoho Mail
49,361; HubSpot 49,015; Mailjet 34,236.
Suite does not equal sender, and our own data proves it. One domain commonly
stacks three providers: a mailbox include (Google or Microsoft), a transactional
include (Amazon SES or SendGrid), and sometimes a security gateway (Mimecast or
Proofpoint). That stacking is why the provider categories sum past 100%:
email-hosting 37.7% + transactional 12.3% + marketing 3.9% + security 2.6%. A
SendGrid SPF record
entry adds SendGrid's entire IP pool to the domain's authorized senders, a
trust decision most operators make once and never revisit.
The denominators matter here too. SendGrid leads
[6sense's transactional-email installed base](https://6sense.com/tech/transactional-email/sendgrid-market-share)
at 23.35% and is a volume monster (Twilio cites SendGrid at more than 200
billion emails a month, self-reported), yet it sits at 2.3% on the SPF axis,
because one company can authorize a provider once while sending billions of
messages through it. Amazon SES publishes no customer count (AWS says SES
"transacts more than a trillion email each year," self-reported). Installed base,
send volume, and SPF send-share are three separate measures — always print the
denominator next to the number.
One naming fact worth getting right: Mailchimp Transactional (Mandrill) is owned
by **Intuit** via its 2021 Mailchimp acquisition — _not_ Sinch. Sinch owns
Mailgun and Mailjet (via Pathwire, 2021); they are two distinct ownership
chains.
Named sender identification — showing "SendGrid," not an anonymous IP block — is
the same suffix-mapping that produced this ranking. It is also how you read your
own SPF record:
[check whether your domain's SPF authorizes a top-share provider](/tools/spf-checker/),
and how many DNS lookups it costs. If you stack several of these providers, the
10-lookup limit (RFC 7208) is closer than it looks, and
[too many SPF DNS lookups](/blog/spf-too-many-dns-lookups/) throws PermError.
148,655 domains (4.8% of SPF-enabled domains) already exceed it; the fix is to
[flatten or prune your SPF record](/tools/spf-flattener/).
## Where webmail brands (Gmail, Outlook, iCloud, Yahoo, Proton) actually land
Consumer webmail brands rank by _inbox_, not by _sending_. Apple Mail and Gmail
are about 90% of email _opens_ (Litmus, Feb 2026), but Apple is invisible on the
sending axis, and Proton, Yahoo, and iCloud barely register among SPF-enabled
business domains, because those are mailbox and read brands, not declared
senders.
This is the distinction the "top email providers" and "top 5 email providers"
listicles blur. On the sending axis, the top brands are infrastructure, not
inboxes: Microsoft 365 (the sender) is not Outlook.com (the consumer inbox), and
Google Workspace (the sender) is not Gmail consumer. A domain authorizes
Microsoft 365 or Google Workspace to _send_; a person opens mail _in_ Gmail or
Apple Mail. These are the same brand families sitting at opposite ends of the
pipe. And picking a top-tier sender is no guarantee of the inbox — see
[why a top provider can still land you in spam](/blog/emails-going-to-spam/).
## Frequently asked questions
### What is the most popular email service provider?
By sending share, Microsoft 365 is the most-used email provider: 603,854
SPF-enabled domains (19.6%) authorize it, ahead of Google Workspace (13.6%), in
a 5.5M-domain Tranco scan (DMARCguard, 2026-03-15). By raw accounts, Gmail leads
with about 1.8 billion users (SellCell, May 2026), a different measure.
### What is the market share of Microsoft 365 in email?
Microsoft 365 holds 19.6% of SPF-enabled domains (603,854 of 3,077,219) on the
sending axis (DMARCguard, 2026-03-15). 6sense's email-management category
independently puts it at 19.97%, within 0.4 points, though it counts company
installs, not domains.
### What is Google Workspace's email market share?
Google Workspace is authorized by 13.6% of SPF-enabled domains (419,733), second
behind Microsoft 365 (DMARCguard, 2026-03-15). It leads the highest-traffic
Tranco tiers (top-1k through top-100k) while Microsoft 365 leads the long tail.
### Who are the top 10 email providers by sending share?
Microsoft 365 (19.6%), Google Workspace (13.6%), GoDaddy (6.6%),
websitewelcome.com (2.5%), Amazon SES (2.5%), SendGrid (2.3%), Mailgun (2.2%),
relay.mailchannels.net (2.2%), Mailchimp (1.9%), and Namecheap (1.7%) of
SPF-enabled domains (DMARCguard, 2026-03-15).
### What is the most used email service in the world?
It depends on the measure. By accounts, Gmail (about 1.8 billion users, SellCell
May 2026). By opens, Apple Mail and Gmail are about 90% (Litmus, Feb 2026). By
business _sending_ infrastructure, Microsoft 365 leads at 19.6% of SPF-enabled
domains (DMARCguard, 2026-03-15). Three measures, three answers.
### Is Microsoft 365 bigger than Google Workspace?
By email-sending share, yes: Microsoft 365 (19.6%) leads Google Workspace
(13.6%) of SPF-enabled domains (DMARCguard, 2026-03-15). By
collaborative-applications revenue, Microsoft also leads (IDC: 30.1% vs 14.7%,
2023 data year). By detected company count, technographic trackers often show
Google ahead.
## The takeaway: pick your axis, then read your own record
The 2026 email provider market share has five answers, not one: opens, MX,
installs, users, and sends. They disagree by design because each counts a
different layer of the email stack:
- On the **sending** axis, Microsoft 365 (19.6%) and Google Workspace (13.6%)
lead, and the top five providers cover 44.8% of all SPF includes.
- **Suite does not equal sender:** the provider categories sum past 100% because
domains stack a mailbox provider, a transactional relay, and sometimes a
security gateway.
- **Denominator is everything:** the same Microsoft 365 reads as 19.6% (sends),
19.97% (installs), ~39% (hosted-email installs), or ~77% (enterprise
productivity) depending on what you measure.
That is the email provider market share on the axis that matters for
deliverability and authentication. Which provider sends for _your_ domain is
already written in your SPF record, and a top-share provider can still land you
in spam if [alignment](/learn/dmarc/) breaks or you cross the 10-lookup limit. For cross-protocol
context, our
[DMARC and DKIM adoption study across the same corpus](/research/email-authentication/)
covers how the rest of the authentication stack holds up.