Tools · customer engagement platforms

Companies using Customer.io_

As of 4 November 2026, 4,735 companies show Customer.io: 4,525 carry it on their website or in their DNS records, 232 name it in their own job postings, and 22 do both.

As of 4 November 2026 · refreshed daily · counts move as websites, DNS and career sites are re-read.

Largest market
United States · 2,004 companies
Companies with 51+ staff
484 · 11% of the footprint
Top industry
Business & finance services · 33%
Team that names it most
Marketing & communications · 275 postings
Hiring on it, last 30 days
169 companies
Most often alongside
Braze · 139 companies
4,735companies show Customer.io, all sources
4,525on their website or in DNS records
232name it in their own job postings
370postings naming Customer.io, last 90 days
02 — Two ways we see a tool

Where Customer.io shows up

Each population is counted on its own. We never add them up without saying so, because they answer different questions.

Website and DNS footprint4,525

Companies whose own pages load Customer.io's scripts or embeds, or whose domain's mail and hosting records (SPF, DKIM, MX, CNAME) point at Customer.io. From our crawl of 41.5M company websites and the DNS sweep behind it. Reach: the tool is in the building.

Job postings232

Companies whose own postings say the team works in Customer.io. Read hourly from ~70 applicant tracking systems, with the function, a quote and a date. Intent: the team that runs it is hiring.

Both22

Companies in the footprint whose postings also name Customer.io. The rest of the posting population (210) runs Customer.io without a public trace on the site or in DNS, which is where job data earns its place.

03 — Who uses it

Companies on Customer.io

Companies with 51+ employees and at least medium-confidence evidence in their own postings; job boards and portals left out.

DD GroupDental equipment distributors · White Notley, United Kingdom201-500 employeesTovalaPrepared meal snack webshops · United States201-500 employeesCocunatBeauty & personal care webshops · Spain51-200 employeesMONEYMEConsumer finance companies · Haymarket, Australia51-200 employeesGreenlyEnergy utility software · Paris 09, France201-500 employeesKoviVehicle rental · Salvador, Brazil1001-5000 employeesSeattle Sounders FCCompetitive sports clubs · United Kingdom51-200 employeesscandiwebEcommerce development agencies · Beacon, United States501-1000 employeesXplore GroupDigital transformation consulting · Kontich, Belgium1001-5000 employeesSmith.aiAI sales voice agents · United States51-200 employeesAutoDSEcommerce merchant apps · Denver, United States51-200 employeesMarcoPolo LearningTeacher professional development · New York, United States51-200 employeesSweatcoinPersonal health tracking apps · Brazil51-200 employeesManychatWhatsapp chatbot platforms · West Hollywood, United States201-500 employeesMittiFacility maintenance management software · Surry Hills, Australia51-200 employeesWPPFull service marketing agencies · Jersey, United Kingdom10,001+ employeesPrimeXBTCrypto exchanges · Atlanta, United States201-500 employeesTatu CityResidential property developers · Nairobi, United Kingdom51-200 employeesSauceRestaurant management software · Miami, United States51-200 employeesMegaportManaged cloud hosting provider · Fortitude Valley, Australia201-500 employees
Seen through the website or DNS only

Companies with 1,000+ employees whose website or DNS carries Customer.io but whose postings never name it: the part of the market job data alone misses.

4,735 companies show Customer.io; 16 of them have over 1,000 employees.

Filter by country, size, team and source, open verified e-mails for the decision makers, or push new matches to your CRM every week.

Free plan: 1,000 records, no card. The first 20 are above; e-mails are verified at the mail server when you open them.

04 — Footprint breakdown

By country, company size and industry

The 4,525 companies with Customer.io on their website or in DNS. Click a country for its own page where we have one.

By country
companiesshare
United States
2,00444%
Australia
1,07924%
United Kingdom
2676%
France
1313%
Germany
1032%
Canada
972%
Netherlands
611%
Brazil
431%
Spain
411%
Sweden
331%
Denmark
261%
Switzerland
251%
By company size
companiesshare
Self-employed
1,32729%
2-10 employees
1,43832%
11-50 employees
1,02423%
51-200 employees
3337%
201-500 employees
952%
501-1000 employees
351%
1001-5000 employees
160%
5001-10000 employees
10%
10,001+ employees
40%
By industry
companiesshare
Business & finance services
1,51333%
Technology & software
1,33429%
Media & content
3688%
Consumer services & leisure
3097%
Health care
1834%
Commerce & trade
1463%
Public, community & associations
952%
Manufacturing & industry
882%
Property & construction
792%
Hospitality & travel
752%
Transport, logistics & rental
421%
Utilities & infrastructure
210%
05 — What their DNS and pages also say

The mail, hosting and web stack of Customer.io companies

Other tools found on the same companies' websites or in their DNS records. Mail providers and senders come from SPF, DKIM and MX; the rest from page code.

Google Workspace2,734 companies · 60%
SendGrid1,815 companies · 40%
Microsoft 3651,621 companies · 36%
Cloudflare1,573 companies · 35%
mailchimp_transactional1,233 companies · 27%
facebook_pixel739 companies · 16%
AWS Route 53738 companies · 16%
Amazon SES656 companies · 14%
Vercel637 companies · 14%
microsoft_intune628 companies · 14%
Microsoft Entra ID625 companies · 14%
meta603 companies · 13%Mailchimp587 companies · 13%HubSpot528 companies · 12%
microsoft_teams517 companies · 11%
Mailgun468 companies · 10%
06 — Job-posting evidence

Who runs Customer.io inside the company

The 232 companies whose postings name Customer.io: by country, size and the function of the role. The second number in the function table is companies.

Postings by function
postings · companies
Marketing & communications
275 · 172
Product, program & project management
32 · 25
Sales
31 · 21
Software engineering
19 · 16
Customer service & success
11 · 10
Data & AI
8 · 7
Travel, leisure & events
8 · 2
General management & consulting
4 · 4
IT operations & business systems
4 · 3
Business development & strategy
2 · 2
Posting companies by country
companiesshare
United States
14864%
United Kingdom
2410%
France
83%
Australia
63%
Canada
52%
Ukraine
42%
Switzerland
31%
Germany
31%
India
31%
United Arab Emirates
21%
Brazil
21%
Netherlands
21%
Posting companies by size
companiesshare
Self-employed
136%
2-10 employees
3013%
11-50 employees
6628%
51-200 employees
5825%
201-500 employees
3415%
501-1000 employees
177%
1001-5000 employees
136%
10,001+ employees
10%
Hiring on it right now
postings
Postings, last 30 days
293
Postings, last 90 days
370
All open postings
452

169 companies opened a role that names Customer.io in the last 30 days. A hiring team that names its tools is the moment to write to the person who owns the stack.

07 — Named alongside

What Customer.io teams also ask for

Tools named in the same postings as Customer.io. Office software is left out.

08 — customer engagement platforms

Customer.io against the rest of its category

Ranked by companies naming each tool in postings. Whole category →

Cite this

Quote the sentence with the date and the link. The numbers change daily; the link always shows the current ones.

4,735 companies show Customer.io: 4,525 carry it on their website or in their DNS records, 232 name it in their own job postings, and 22 do both. (Breaknorm, 4 November 2026, https://breaknorm.co/tools/customer-io)
How we know

Read from the source, not self-reported

Every number on this page can be traced to a page we crawled or a posting we read. Full methodology →

  • Website codeScripts, tags and embeds found on the company's own pages in our crawl of 41.5M sites. A tool counts once per company.
  • DNS recordsSPF includes, DKIM selectors, MX and CNAME records of the company's domain that point at Customer.io or another vendor. Swept in cycles; dedicated mail-provider and hosting facets open once coverage passes 80% per country.
  • Job postingsRead hourly from the applicant tracking systems behind company career sites. A tool counts when the employer's own text names it as the team's system; candidate wish-lists and apply boilerplate are excluded. Confidence low, medium or high per company.
  • Sending infrastructureCold-e-mail sending domains are look-alike domains on a provider's infrastructure (DNS records, certificate logs) that redirect to the company. Absence is not evidence: only companies with a found sending domain are counted.
  • CompaniesCountry, size and industry come from the company profile we build from its website; headcount from LinkedIn where known, otherwise estimated. Job boards, portals and aggregators are kept out of lists.
FAQ

Customer.io data: questions

How many companies use Customer.io?

4,735 as of 4 November 2026: 4,525 carry Customer.io on their website or in their DNS records and 232 name it in their own job postings; 22 show up in both. We keep the two counts apart because they measure different things.

What does "website or DNS" mean?

Our crawler finds Customer.io's scripts, embeds and tags on the company's own pages, and our DNS sweep reads the domain's mail and hosting records (SPF includes, DKIM selectors, MX, CNAMEs) that point at Customer.io. Either one puts the company in the footprint. The sweep is still running, so this number grows week by week.

Why is the job-posting number so much smaller?

A posting only names a tool when the team that will use it is hiring and chooses to say so. That makes it a smaller but stronger signal: it tells you which team runs Customer.io, with a quote and a date. The footprint tells you reach.

How fresh is this?

Career sites are read hourly, websites are re-crawled on a rolling schedule and DNS is re-swept in cycles. The date at the top is when these counts were computed.

Can I get the list?

Yes. The first 20 are on this page; the full 4,735 with verified e-mails and a weekly feed of new Customer.io users is in the product. Counting is free.

Companies and people

Get this list your way

The same data as a search, over MCP and the API, as bulk files, or pushed to you as it changes.

Every company on Customer.io,
with the person who owns it

Connect the MCP server or the API, filter on Customer.io, and get 1,000 records free.

  1. 01Sign up, no card
  2. 02Connect Claude, ChatGPT or an API key
  3. 03Ask for your market, 1,000 records free