Companies Using Customer.io
Behavioral messaging platform that helps companies send targeted emails, push notifications, and SMS based on real-time customer actions and events.
We detected 2,836 customers using Customer.io and 1,236 companies enriched with company data and generated the page insights. The most common industry is Software Development (20%) and the most common company size is 1-10 employees (53.5%). We also know of 11,241 sites that have used Customer.io previously.
Published Feb 26, 2026 · Updated Feb 26, 2026 · Data analysed on February 26, 2026.
Customer.io Usage Statistics
Customer.io showed steady, organic growth since its first detection in late 2012 — the same year co-founders Colin Nederkoorn and John Allison launched the platform with just 5 customers. By 2019 the install base had reached about 200 active domains, before a dramatic surge in late 2020 nearly tripled it in a single month (219 → 550 domains). Growth accelerated further through 2023-2024, peaking at 2,487 active domains in December 2024. In September 2025, the company announced it had crossed $100M in annual recurring revenue, with 8,000+ companies sending 64 billion messages per year across email, push, SMS, and in-app channels.
List of Companies Using Customer.io
The company list spans from enterprise brands like Seagate and The Economist to high-growth SaaS companies like Apollo.io, G2, and Mapbox, reflecting Customer.io's strength among tech-forward businesses. E-learning platforms (DataCamp, Platzi, Twenix) and fintech companies are also well-represented.
Download all 2,836 Customer.io customers with full company data, or create a signal to track when companies start or stop using Customer.io.
| Company | Detection URL | Domain | Country | Industry | Employees | Type | Founded | |
|---|---|---|---|---|---|---|---|---|
| seagate.com | seagate.com | United States | Computer Hardware Manufacturing | 10001+ | Public Company | 1979 | https://linkedin.com/company/seagate-technology | |
| exeter.ac.uk | exeter.ac.uk | United Kingdom | Higher Education | 1001-5000 | Educational | 1955 | https://linkedin.com/company/university-of-exeter | |
| mba-scholarship.gmat.economist.com | economist.com | United Kingdom | Newspaper Publishing | 1001-5000 | Privately Held | 1843 | https://linkedin.com/company/the-economist | |
| app.clinic.weightwatchers.com | weightwatchers.com | United States | Wellness and Fitness Services | 1001-5000 | Public Company | 1963 | https://linkedin.com/company/weightwatchers | |
| fund.revgenius.com | revgenius.com | United States | Think Tanks | 1-10 | Privately Held | 2020 | https://linkedin.com/company/revgenius | |
| math.skyeng.ru | skyeng.ru | Cyprus | Professional Training and Coaching | 1001-5000 | Public Company | 2010 | https://linkedin.com/company/skyeng | |
| tryhackme.com | tryhackme.com | United Kingdom | Computer and Network Security | 51-200 | Public Company | 2018 | https://linkedin.com/company/tryhackme | |
| bancomediolanum.es | bancomediolanum.es | Spain | Banking | 1001-5000 | Privately Held | 1983 | https://linkedin.com/company/banco-mediolanum | |
| webstaurantstore.com | webstaurantstore.com | United States | Wholesale | 5001-10000 | Privately Held | 2004 | https://linkedin.com/company/webstaurantstore-com | |
| community.kodnest.com | kodnest.com | India | Software Development | 51-200 | Privately Held | 2017 | https://linkedin.com/company/kodnestoffice |
Show all 39 companies (29 more)
| Company | Detection URL | Country | Industry | Employees | Type | Founded | ||
|---|---|---|---|---|---|---|---|---|
| app.apollo.io | apollo.io | United States | IT Services and IT Consulting | 501-1000 | Privately Held | 2010 | https://linkedin.com/company/apolo-cyse | |
| feedback.empik.com | empik.com | Poland | Retail | 1001-5000 | Privately Held | 1948 | https://linkedin.com/company/empik-group | |
| datacamp.com | datacamp.com | United States | E-Learning Providers | 51-200 | Privately Held | 2013 | https://linkedin.com/company/datacampinc | |
| unesc.net | unesc.net | Brazil | Education Administration Programs | 1001-5000 | Educational | 1968 | https://linkedin.com/company/unesc | |
| balearia.com | balearia.com | Spain | Maritime Transportation | 1001-5000 | Privately Held | 1998 | https://linkedin.com/company/balearia | |
| swingeducation.com | swingeducation.com | United States | Education Administration Programs | 51-200 | Privately Held | 2015 | https://linkedin.com/company/swing-education | |
| builder.ai | builder.ai | United Kingdom | Software Development | 501-1000 | Privately Held | 2012 | https://linkedin.com/company/builderai | |
| productmarketingalliance.com | productmarketingalliance.com | United States | Education | 51-200 | Educational | 2019 | https://linkedin.com/company/product-marketing-alliance | |
| g2.com | g2.com | United States | Technology, Information and Internet | 501-1000 | Privately Held | 2012 | https://linkedin.com/company/g2dotcom | |
| prix-immobilier.leparisien.fr | leparisien.fr | France | Newspaper Publishing | 501-1000 | Privately Held | 1944 | https://linkedin.com/company/le-parisien | |
| breezy.hr | breezy.hr | United States | Software Development | 11-50 | Privately Held | 2014 | https://linkedin.com/company/breezyhr | |
| mapbox.com | mapbox.com | United States | Software Development | 501-1000 | Privately Held | 2011 | https://linkedin.com/company/mapbox | |
| glints.com | glints.com | Singapore | Human Resources Services | 201-500 | Privately Held | 2013 | https://linkedin.com/company/glints | |
| capsule.com | capsule.com | United States | Technology, Information and Internet | 501-1000 | Privately Held | 2016 | https://linkedin.com/company/capsule-co | |
| ebaconline.com.br | ebaconline.com.br | Brazil | E-Learning Providers | 51-200 | Educational | 2016 | https://linkedin.com/company/ebac-escola-britanica-artes-criativas | |
| feedback.gwi.com | gwi.com | United States | Data Infrastructure and Analytics | 501-1000 | Privately Held | 2009 | https://linkedin.com/company/gwidotcom | |
| subscription.qa.cookunity.com | cookunity.com | United States | Food and Beverage Manufacturing | 501-1000 | Privately Held | 2015 | https://linkedin.com/company/cookunity | |
| myaccount.welcometothejungle.com | welcometothejungle.com | France | Technology, Information and Internet | 201-500 | Partnership | 2014 | https://linkedin.com/company/wttj-fr | |
| garantibbva.ro | garantibbva.ro | Romania | Banking | 1001-5000 | Privately Held | — | https://linkedin.com/company/garanti-bbva-romania | |
| notionpress.com | notionpress.com | India | Book and Periodical Publishing | 51-200 | Privately Held | 2012 | https://linkedin.com/company/notion-press | |
| harri.com | harri.com | United States | Software Development | 501-1000 | Privately Held | 2012 | https://linkedin.com/company/harri-com | |
| platform.twenix.com | twenix.com | Spain | E-Learning Providers | 51-200 | Privately Held | 2017 | https://linkedin.com/company/twenix | |
| gorgias.com | gorgias.com | United States | Software Development | 201-500 | Privately Held | 2015 | https://linkedin.com/company/gorgias | |
| logrocket.com | logrocket.com | United States | Software Development | 501-1000 | Privately Held | 2016 | https://linkedin.com/company/logrocket | |
| la-spa.fr | la-spa.fr | France | Civic and Social Organizations | 501-1000 | Nonprofit | 1845 | https://linkedin.com/company/la-spa | |
| roadmap.platzi.com | platzi.com | United States | E-Learning Providers | 11-50 | Educational | 2012 | https://linkedin.com/company/platzi-inc | |
| viki.com | viki.com | United States | Entertainment Providers | 51-200 | Privately Held | 2010 | https://linkedin.com/company/viki | |
| careersupport.masterschool.com | masterschool.com | United States | Research Services | 51-200 | Privately Held | 2021 | https://linkedin.com/company/joinmasterschool | |
| insighttimer.com | insighttimer.com | Australia | Wellness and Fitness Services | 51-200 | Privately Held | 2009 | https://linkedin.com/company/insight-network-inc |
Showing 10 of 39 companies — expand above to see all
Customer.io Customers by Country
The United States dominates with 55.5% of all matched companies, followed by the United Kingdom (9.1%) and Canada (6.0%). English-speaking countries account for over 72% of the user base. Notably, Spain (5.6%) and France (4.0%) round out the top 5 — a European presence that distinguishes Customer.io from more US-centric competitors.
Customer.io Market Share & Overview
Customer.io holds approximately 0.20% of the marketing automation market by domain count, ranking outside the top 50. However, raw domain detections understate its true footprint — the company reports 8,000+ paying customers and crossed $100M ARR in September 2025, suggesting a high-ARPU, enterprise-leaning revenue model. Its user base is heavily concentrated in Software Development (20%) and Technology (14.3%), indicating a deeply specialized niche among technically sophisticated companies.
Top Competitors by Market Share
Customer.io Customers by Company Size & Age
Customer.io's user base is overwhelmingly small business — 81% have 50 or fewer employees, with the 1-10 segment alone accounting for 53.5%. Only 3.0% of customers have more than 500 employees, making this one of the most SMB-concentrated profiles in the marketing automation category.
Company Size Distribution
Company Age (Founded Decade)
Customer.io Customers by Industry
Software Development dominates at 20.0%, followed by Technology, Information and Internet at 14.3%. Together, tech-related industries account for over 40% of the user base — a concentration 3-4x higher than mass-market tools like Mailchimp. This signals that Customer.io is the messaging platform of choice for product-led tech companies.
Customer.io Alternatives & Competitors
Customer.io competes in the broader marketing automation space dominated by MailChimp (19.5%) and Klaviyo (10.2%). Its closest functional competitors — Drip and ActiveCampaign — similarly target data-driven, event-based communication. While Customer.io trails in raw volume, its tech-heavy user base and developer-first approach position it uniquely in the behavioral messaging segment.
| Technology | Domains | Market Share |
|---|---|---|
 | 283,090 | 19.54% |
 | 147,491 | 10.18% |
 | 121,300 | 8.37% |
 | 95,861 | 6.62% |
 | 72,439 | 5% |
Customer.io Customer Migration: Competitor Gains & Losses
Based on 1,235 enriched companies, Customer.io sees significant migration activity with larger competitors. HubSpot is the dominant migration partner — Customer.io gained 145 companies from HubSpot but lost 318 (net -173). MailChimp shows a more balanced flow: 169 gains vs 147 losses (net +22), suggesting Customer.io successfully attracts users outgrowing basic email tools.
| Competitor | Gained | Lost | Net |
|---|---|---|---|
| +145 | -318 | -173 |
| +169 | -147 | +22 |
 | +76 | -76 | 0 |
| +68 | -79 | -11 |
 | +35 | -66 | -31 |
| +22 | -73 | -51 |
 | +38 | 0 | +38 |
| 0 | -33 | -33 |
What Other Technologies Do Customer.io Customers Use?
Based on 1,235 enriched companies, the most distinctive co-occurring technology is Intercom at 37.4% — far above typical benchmarks — signaling that Customer.io customers are predominantly product-led SaaS companies. WordPress (32.1%) and Vue.js (22.6%) round out the non-analytics stack, while Google Analytics (81.9%) and Facebook Pixel (39.8%) reflect standard marketing instrumentation.
Web Analytics
Live Chat
CMS
JavaScript Frameworks
E-Commerce
Customer.io Customer Reviews with Pros and Cons
Based on aggregated G2 reviews, Customer.io scores highest for ease of use (223 mentions) and automation capabilities (140 mentions). The most common criticism is a steep learning curve (86 mentions), particularly around advanced workflows and onboarding — a tension typical of powerful, developer-oriented platforms.
Generated from real user reviews on G2
- Users find Customer.io's ease of use in building campaigns and integrating with tools exceptionally beneficial for marketing.(223 reviews)
- Users value the automation capabilities of Customer.io, enabling effortless campaign management without needing tech support.(140 reviews)
- Users value the helpful customer support of Customer.io, enhancing their experience with the platform significantly.(132 reviews)
- Users find Customer.io's helpful support and ease of use invaluable for their email marketing efforts.(128 reviews)
- Users appreciate the ease of use and comprehensive features of Customer.io, enabling seamless marketing campaign creation.(121 reviews)
- Users find the learning curve steep, often struggling with complexity and product integration challenges during onboarding.(86 reviews)
- Users find the missing features in Customer.io limit campaign effectiveness and hinder data-driven marketing opportunities.(74 reviews)
- Users find limited features in Customer.io, impacting analytics, segmentation, and campaign optimization effectiveness.(51 reviews)
- Users express concerns about campaign issues, including performance slowdowns and limited analytics capabilities for large campaigns.(44 reviews)
- Users often find the user interface unintuitive, leading to a steep learning curve and cumbersome navigation.(38 reviews)
Top Companies That Use Customer.io: Expert Signals for Sales & Tech Adoption
With 10+ years in web crawling and data intelligence, I've analyzed Customer.io's install base across 2,836 active domains matched to 1,236 enriched company profiles (43.6% match rate). Customer.io isn't chasing volume — it's the automation tool of choice for technically sophisticated teams. Here are 3 signals that should shape your outbound strategy.
1. The SaaS-Heavy Signal (34.3% Software + Tech)
Key Insight: Software Development (20%) and Technology, Information and Internet (14.3%) combine for over 34% of Customer.io's user base — a concentration 3-4x higher than you'd see with Mailchimp or Klaviyo. These are product-led companies that need event-driven messaging, not newsletter blasts.
Prospecting: Target SaaS companies (11-50 employees, founded 2010-2020) with subject lines like "Your onboarding emails could trigger on user behavior — here's how [Company] teams do it." Expected open rate: 28-35%.
2. The Intercom Overlap Signal (37.4% Co-Occurrence)
Key Insight: 37.4% of Customer.io companies also use Intercom — the highest co-occurrence rate in our dataset. This isn't coincidence: both tools serve product-led growth teams. Companies using Intercom for in-app chat likely need Customer.io for lifecycle email and push notifications.
Prospecting: Build a prospect list of Intercom users NOT yet on Customer.io. Ad copy: "You're already talking to users in-app with Intercom. Now automate the lifecycle emails that bring them back." Expected CTR: 2.1-3.0%.
3. The Digital-Native Company Signal (84% Founded 2010+)
Key Insight: 84% of Customer.io companies were founded in 2010 or later, with 30% from the 2020s alone. This is overwhelmingly a digital-native user base. Combined with the 53.5% of companies having 1-10 employees, the ideal Customer.io customer is a small, recently founded SaaS startup.
Prospecting: Target seed-to-Series A startups on Crunchbase or AngelList with subject lines like "Most startups your size use Customer.io for behavior-triggered emails — here's what they automate first." Expected reply rate: 4-6%.
Quick Pipeline Hacks
Email: Segment by "SaaS companies using Intercom + no Customer.io detection" for highest-converting outbound lists.
Ads: Run LinkedIn ads targeting Product Marketing and Growth roles at companies with 11-50 employees in Software Development — Customer.io's sweet spot.
Pro Tip: Customer.io's net migration is negative vs HubSpot (-173 companies) — meaning HubSpot is winning in head-to-head switches. Position against HubSpot's all-in-one complexity by emphasizing Customer.io's developer-friendly APIs and event-based flexibility.
Transform these technographic signals into targeted pipeline today.
Frequently Asked Questions
Who uses Customer.io?
Customer.io is used by 2,836 companies worldwide, including Seagate, University of Exeter, The Economist Group. It's particularly popular in the Software Development industry (20% of customers).
How many customers does Customer.io have?
Based on our detection data, Customer.io has 2,836 active customers. We enriched 1,236 of these with LinkedIn company data to generate our insights. Additionally, 11,241 sites have previously used Customer.io.
What is Customer.io's market share?
Customer.io holds 0.2% of the Marketing Automation market, ranking #55 in the category.
What are the best alternatives to Customer.io?
The top alternatives to Customer.io include MailChimp (19.54% market share), Klaviyo (10.18% market share), HubSpot (8.37% market share), MailerLite (6.62% market share).
Which countries use Customer.io the most?
United States leads with 552 customers, followed by United Kingdom (91), Canada (60), Spain (56), France (40).
What size companies use Customer.io?
The most common company size is 1-10 employees, representing 53.5% of Customer.io customers. This is followed by 11-50 employees (27.5%) and 51-200 employees (12.9%).
How old are companies that use Customer.io?
The majority of Customer.io customers were founded in the 2010s (53.98%), followed by the 2020s (30.2%). This suggests Customer.io is most popular among relatively young companies.
What is the ideal customer profile for Customer.io?
Based on 1,236 analyzed companies, the ideal Customer.io customer is: Company Size: 1-10 employees, Location: US, UK, or Canada, City: New York, San Francisco, London, Founded: 2010-2019, Company Age: ~5-15 years old.
What is Customer.io?
Customer.io is a behavioral messaging platform for tech-savvy marketers who want more control and flexibility to craft and send data-driven emails, push notifications, in-app messages, and SMS. Founded in 2012 by Colin Nederkoorn and John Allison, it grew from 5 initial customers to 8,000+ companies and crossed $100M in annual recurring revenue in September 2025. It differentiates itself through event-driven automation that triggers messages based on what people do — or don't do — in real time, making it especially popular among product-led SaaS companies.
What is the source of this data?
These insights include all TechnologyChecker.io detections of Customer.io (free & paid plans). Our platform has tracked over 2.08 billion total detections across a 20+ year detection history, crawling 29.6 million domains and monitoring 44,000+ technologies with a 31.6% company match rate. Need paid-only or company data filtering? Register at TechnologyChecker.io.
How often is the data updated?
We update all data every month. Our crawler scans over 2 billion URLs across 30 million domains each cycle, detecting both frontend and backend technologies to ensure comprehensive, up-to-date coverage.
How to find companies that use Customer.io?
You can find companies using Customer.io through TechnologyChecker.io's technology detection tool. It scans both frontend and backend technologies using numerous detection methods — including script analysis, DNS records, HTTP headers, and HTML patterns — to accurately identify which technologies a website uses.
Based on 1,236 company data
These insights include all Technologychecker.io detections of Customer.io (free & paid plans). Need paid-only or company data filtering?