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EmailValidly Research · YC company cohort

Email provider
market share tracker.

Who receives mail for today’s startups? Explore observed MX routes by industry, country and reported team size. Every figure links back to a dated sample.

Read the methodology
5,112Domains in this view
98.9%DNS lookups without errors
2026-09-06Snapshot completed (UTC)
Download evidence CSVJSON data

Share of observed domains

Each domain counts once. All results—including unknown and no-MX responses—remain in the denominator.

Google Workspace77.4% · 3959
Mixed routes5.5% · 280
Microsoft 3655.0% · 257
No MX4.8% · 243
Other / unclassified3.3% · 170
Security gateway1.3% · 65
DNS unknown1.1% · 54
Null MX0.5% · 26
Zoho0.5% · 25
Custom-domain MX0.4% · 22
Proton Mail0.1% · 5
Fastmail0.1% · 4
Apple iCloud0.0% · 2

A statistic with context

Cite the finding

In EmailValidly’s 2026-09-06 MX snapshot of 5112 YC company domains, 3959 (77.4%) were classified as Google Workspace. This measures published incoming mail routes, not global market share or paid subscriptions.

Sample scope

This cohort covers publicly listed YC companies with Active, Acquired or Public status and a valid website domain. It does not represent all companies or the global email market. Small slices are descriptive, not representative estimates.

Source limitations

Country is the directory’s listed geography, not mail-server location. Company attributes are reported by the source and may be incomplete or stale.

Inspect the evidence

The table shows each domain’s classification and exact MX hosts. Download the complete filtered view for priorities, timestamps and source links.

Company / domainObserved routeIndustryCountryTeam size
100x100x.botGoogle Workspace1 smtp.google.comProductivityIndia1–10
10 By 1010by10.ioGoogle Workspace1 aspmx.l.google.com · 5 alt1.aspmx.l.google.com · 5 alt2.aspmx.l.google.com · 10 aspmx2.googlemail.com · 10 aspmx3.googlemail.comRecruiting and TalentUnited States of America1–10
10x10xdental.comGoogle Workspace1 smtp.google.comHealthcareUnited States of America1–10
10x Science10xscience.comGoogle Workspace1 smtp.google.comB2BUnited States of America1–10
All Screen140fire.comNo MXNo published MX; SMTP address fallback may still existMarketingUnited States of America11–50
1849 bio1849.bioGoogle Workspace1 aspmx.l.google.com · 5 alt1.aspmx.l.google.com · 5 alt2.aspmx.l.google.com · 10 alt3.aspmx.l.google.com · 10 alt4.aspmx.l.google.comIndustrialsUnited States of America1–10
19101910.aiGoogle Workspace1 smtp.google.comTherapeuticsUnited States of America11–50
One Degree1degree.orgGoogle Workspace1 aspmx.l.google.com · 5 alt1.aspmx.l.google.com · 5 alt2.aspmx.l.google.com · 10 aspmx2.googlemail.com · 10 aspmx3.googlemail.comUnspecifiedUnited States of America11–50
1stCollab1stcollab.comGoogle Workspace1 aspmx.l.google.com · 5 alt1.aspmx.l.google.com · 5 alt2.aspmx.l.google.com · 10 alt3.aspmx.l.google.com · 10 alt4.aspmx.l.google.comMarketingUnited States of America11–50
21st21st.devGoogle Workspace1 aspmx.l.google.com · 5 alt1.aspmx.l.google.com · 5 alt2.aspmx.l.google.com · 10 alt3.aspmx.l.google.com · 10 alt4.aspmx.l.google.comEngineering, Product and DesignUnited States of America1–10
222222.placeGoogle Workspace1 aspmx.l.google.com · 5 alt1.aspmx.l.google.com · 5 alt2.aspmx.l.google.com · 10 alt3.aspmx.l.google.com · 10 alt4.aspmx.l.google.comConsumerUnited States of America11–50
280 North280north.comNo MXNo published MX; SMTP address fallback may still existEngineering, Product and DesignUnited States of America11–50
42Floors42floors.comNo MXNo published MX; SMTP address fallback may still existHousing and Real EstateUnited States of America51–200
4242technologies.comGoogle Workspace1 aspmx.l.google.com · 5 alt1.aspmx.l.google.com · 5 alt2.aspmx.l.google.com · 10 aspmx2.googlemail.com · 10 aspmx3.googlemail.comRetailUnited States of AmericaUnknown
500Friends500friends.comSecurity gateway10 mxa-00315601.gslb.pphosted.com · 10 mxb-00315601.gslb.pphosted.comRetailUnited States of America51–200
64x Bio64xbio.comGoogle Workspace10 aspmx.l.google.com · 20 alt1.aspmx.l.google.com · 30 alt2.aspmx.l.google.com · 40 alt2.aspmx.l.google.com · 50 alt4.aspmx.l.google.comIndustrial BioUnited States of America11–50
6thSense6thsense.devGoogle Workspace1 smtp.google.comManufacturing and RoboticsUnited States of America1–10
7cups7cups.comGoogle Workspace1 aspmx.l.google.com · 5 alt1.aspmx.l.google.com · 5 alt2.aspmx.l.google.com · 10 alt3.aspmx.l.google.com · 10 alt4.aspmx.l.google.comHealthcare ServicesUnited States of America11–50
80,000 Hours80000hours.orgGoogle Workspace1 aspmx.l.google.com · 5 alt1.aspmx.l.google.com · 5 alt2.aspmx.l.google.com · 10 alt3.aspmx.l.google.com · 10 alt4.aspmx.l.google.comUnspecifiedUnited Kingdom11–50
83 Sciences83sciences.aiGoogle Workspace1 smtp.google.comIndustrialsUnited States of America1–10
99minutos99minutos.comGoogle Workspace1 smtp.google.comSupply Chain and LogisticsMultiple countries1,001+
9gag9gag.comGoogle Workspace10 aspmx.l.google.com · 20 alt1.aspmx.l.google.com · 30 aspmx3.googlemail.com · 30 aspmx4.googlemail.com · 30 aspmx5.googlemail.comSocialHong Kong11–50
9 Mothers9mothers.comMicrosoft 36510 9mothers-com.mail.protection.outlook.comDefenseUnited States of America11–50
a0.deva0.devGoogle Workspace1 smtp.google.comEngineering, Product and DesignUnited States of America1–10
A1Zap by A1Basea1zap.comOther / unclassified10 mail.a101.botEngineering, Product and DesignUnited States of America1–10
Abacumabacum.aiGoogle Workspace1 smtp.google.comFinance and AccountingUnited States of America51–200
Abacusabacus.comGoogle Workspace10 aspmx.l.google.com · 20 alt1.aspmx.l.google.com · 20 alt2.aspmx.l.google.com · 30 aspmx2.googlemail.com · 30 aspmx3.googlemail.comFinance and AccountingUnited States of America11–50
Abalone Bioabalonebio.comGoogle Workspace1 aspmx.l.google.com · 5 alt1.aspmx.l.google.com · 5 alt2.aspmx.l.google.com · 10 alt3.aspmx.l.google.com · 10 alt4.aspmx.l.google.comDrug Discovery and DeliveryUnited States of America11–50
Abatableabatable.comGoogle Workspace1 aspmx.l.google.com · 5 alt1.aspmx.l.google.com · 5 alt2.aspmx.l.google.com · 10 alt3.aspmx.l.google.com · 10 alt4.aspmx.l.google.comClimateUnited Kingdom11–50
Abel Policeabelpolice.comGoogle Workspace1 smtp.google.comGovernmentUnited States of America1–10
Abhiabhi.com.pkGoogle Workspace1 aspmx.l.google.com · 5 alt1.aspmx.l.google.com · 5 alt2.aspmx.l.google.com · 10 alt3.aspmx.l.google.com · 10 alt4.aspmx.l.google.comCredit and LendingPakistan1–10
AbInitio Bioabinitio-bio.comGoogle Workspace1 smtp.google.comDrug Discovery and DeliveryUnited States of America1–10
Able Healthablehealth.comGoogle Workspace1 aspmx.l.google.com · 5 alt1.aspmx.l.google.com · 5 alt2.aspmx.l.google.com · 10 aspmx2.googlemail.com · 10 aspmx3.googlemail.comHealthcare ITUnited States of America11–50
Ableablejobs.coNo MXNo published MX; SMTP address fallback may still existJob and Career ServicesIndia11–50
Abstraabstra.ioGoogle Workspace1 aspmx.l.google.com · 5 alt1.aspmx.l.google.com · 5 alt2.aspmx.l.google.com · 10 alt3.aspmx.l.google.com · 10 alt4.aspmx.l.google.comEngineering, Product and DesignBrazil11–50
Absurdabsurd.comGoogle Workspace1 smtp.google.comMarketingUnited States of America1–10
Abundantabundant.aiGoogle Workspace1 smtp.google.comB2BUnited States of America1–10
Accept.inc (formerly BoardRE)accept.incDNS unknownDNS information was unavailable at the time of this check.Credit and LendingUnited States of America51–200
AccessOwlaccessowl.ioGoogle Workspace1 smtp.google.comInfrastructureGermany11–50
AccioJobacciojob.comGoogle Workspace1 aspmx.l.google.com · 5 alt1.aspmx.l.google.com · 5 alt2.aspmx.l.google.com · 10 alt3.aspmx.l.google.com · 10 alt4.aspmx.l.google.comEducationIndia51–200
Acelyacely.comGoogle Workspace1 smtp.google.comEducationUnited States of America11–50
ACLUaclu.orgSecurity gateway0 mxa-00331601.gslb.pphosted.com · 0 mxb-00331601.gslb.pphosted.comUnspecifiedUnited States of America201–1,000
Acoliteacolite.aiGoogle Workspace1 smtp.google.comInsuranceUnited States of America1–10
Acrelyacrely.aiGoogle Workspace1 smtp.google.comB2BUnited States of America1–10
Actiondeskactiondesk.ioGoogle Workspace1 aspmx.l.google.com · 5 alt1.aspmx.l.google.com · 5 alt2.aspmx.l.google.com · 10 alt3.aspmx.l.google.com · 10 alt4.aspmx.l.google.comEngineering, Product and DesignUnited States of America1–10
Actipulse Neuroscienceactipulseneuroscience.comNo MXNo published MX; SMTP address fallback may still existMedical DevicesMexico11–50
Activeloopactiveloop.aiMixed routes1 aspmx.l.google.com · 5 alt1.aspmx.l.google.com · 5 alt2.aspmx.l.google.com · 10 alt3.aspmx.l.google.com · 10 alt4.aspmx.l.google.com · 15 bbdlnfbityfi5jb7pc4dzs6n26o22u2btlawbkbv5pgyr4lhzuqq.mx-verification.google.comInfrastructureUnited States of America11–50
Activepiecesactivepieces.comGoogle Workspace1 aspmx.l.google.com · 5 alt1.aspmx.l.google.com · 5 alt2.aspmx.l.google.com · 10 alt3.aspmx.l.google.com · 10 alt4.aspmx.l.google.comEngineering, Product and DesignUnited States of America1–10
Acunoteacunote.comOther / unclassified10 minishark.pluron.comProductivityUnited States of AmericaUnknown
ACXacxtherapeutics.comGoogle Workspace1 smtp.google.comIndustrial BioUnited States of America1–10
How the numbers are made

Public records. Explicit limits.

01 · Define the cohort

We source company websites and reported attributes from the YC OSS company directory, a community-maintained mirror of the public YC directory. The sample includes companies listed as Active, Acquired or Public with a usable website domain. Each domain counts once. Where several companies share a domain, company details may be shown as unknown. Industry filters include parent categories such as Fintech; the evidence table shows the most specific category.

02 · Observe the mail route

We check each domain’s published MX records to see where incoming email is routed. The downloadable results include mail-server names, priorities and the time of each check. No inboxes are contacted and no email is sent. You can compare dated snapshots as new results become available.

03 · Classify conservatively

Published mail-server names help identify Google Workspace, Microsoft 365, Zoho, Proton Mail and other recognizable routes. Security gateways and mixed routes remain separate. A custom-domain mail server is not proof of self-hosting, so we label it “Custom-domain MX.” Unrecognized hosts remain unclassified.

04 · Keep the denominator visible

Share means domains in a provider category divided by every domain in the selected view. Missing MX, null MX and DNS failures remain visible. We do not estimate seats, revenue or paid subscriptions. A domain can publish Google or Microsoft routing without proving a specific product plan.

Classification references: Google MX setup, Microsoft DNS setup, Zoho email delivery, Proton custom domains. Independent research; not affiliated with YC or these providers.

Questions about this research

Does this measure global email-provider market share?

No. It measures the distribution of publicly observed incoming mail routes in the specified YC domain cohort. YC-backed companies are a selected population. When citing a finding, include the selected industry or country, sample size and snapshot date so readers know which companies it describes.

Can MX records reveal self-hosting or the provider behind a gateway?

Not reliably. A security gateway can relay mail to Google, Microsoft or an internal server. A custom hostname can point at managed infrastructure. We retain those distinctions rather than assigning a provider without evidence.

Why do country and company-size filters have unknown values?

These filters come from directory metadata, not DNS. Remote companies may not list a single country; a zero or missing team size is treated as unknown. Multiple listed countries are grouped separately. Sizes reflect reported teams, not verified payroll counts.

How often is the tracker updated?

We aim to publish a new snapshot each week. The date shown tells you when the displayed results were collected. If an update is delayed, the previous results remain available with their original date. Use the snapshot selector to browse earlier results.

May I cite or download the results?

Use the citation and CSV controls to capture the selected cohort, date, numerator and denominator. Link to the saved view and mention EmailValidly’s MX observations. Company metadata belongs to its respective sources; this page does not grant additional rights to third-party data.

Check a domain’s MX recordsInspect SPF and DMARCCheck blocklist statusCheck deliverability signals