636 companies use Customer.io, as of October 2026.
Customer.io: Messaging automation. We've found 636 companies using Customer.io, most often in Software (17%) and Financial Services (15%), typically with 51–200 employees and 50% based in United States.
Customers636companies use it
Most popular withConsumer Finance59× more likely than average
Typical customer51–200employees · mostly United States
We've found 636 companies using Customer.io among the 183,224 we've scanned so far. We only count a company when a direct public record backs it up.
What kind of companies use Customer.io?
Customer.io customers are most often in Software (17%), Financial Services (15%) and Internet (10%). The most common company size is 51–200 employees (35% of customers with a known size).
Which countries use Customer.io the most?
Most Customer.io customers we've found are in United States (50%), Australia (6%) and United Kingdom (5%).
What are the alternatives to Customer.io?
The most used alternatives in the same category are Mailchimp (22,226 companies), Brevo (19,811 companies), Pardot (9,767 companies) and Klaviyo (7,348 companies).
How does runsonwhat know a company uses Customer.io?
We read public traces only. For Customer.io that means the company's email records (SPF, MX, DKIM), a subdomain that points at Customer.io, code loaded on the company's website, including tag managers and the company's published subprocessor list. Every match keeps the record it came from.
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