Customer.io vs OneSignal: who uses which
Customers, public proof and the companies that use both.
On usedby, 35 companies use Customer.io and 40 use OneSignal. 1 company uses both, including Capacity. Customer.io leads among the Artificial Intelligence companies on usedby that use either tool.Latest check Nov 13, 2026: 75 of 75 public lines checked. Counts include every proof level, job-post signals included. A company on both tools counts at any proof level, and a job post on one side is marked as such.
Who uses Customer.io, OneSignal, or both
Every company with a public proof for at least one of the two tools.
34
listed for Customer.io only
1
company uses both
39
listed for OneSignal only
On usedby, 34 companies are listed for Customer.io only, 39 are listed for OneSignal only and 1 uses both, out of the 74 companies listed for at least one. An absent listing does not prove non-use.
Who uses both
Companies with a public line on both tools, at any proof level: the strongest proofs come first, and a job post is marked.
| Company | First public proof, Customer.io | First public proof, OneSignal |
|---|---|---|
 Capacity | On or before Nov 2026 | On or before Nov 2026 |
Side by side
Facts from our data and from each vendor's public pages. Each line says where it comes from.
Vendor facts checked: Customer.io, 3 of 6; OneSignal, 3 of 6. Missing facts remain unverified, not absent features.
Customer.io
OneSignalWhat customers report
Results as the vendor or the customer published them, with the source and the date.
Customer.io
80% of users who started the Nudge onboarding survey completed it and were enrolled in the monthly program
Kinnect.Club
Vendor case study, customer.io, published Dec 2, 2025
monthly send volume increased by more than 2,000%
Georgia Aquarium
Vendor case study, customer.io, published Apr 23, 2026
OneSignal
the number of subscribers opted-in to RFE increased by 35% across both web and mobile sites
Radio Free Europe
Vendor case study, onesignal.com, published May 11, 2020
MuteSix generates 182% increase in total revenue within first month of switching to OneSignal
MuteSix
Vendor case study, onesignal.com, published Jul 15, 2020
Questions about Customer.io and OneSignal
Which is used more, Customer.io or OneSignal?
OneSignal has more customers on usedby: 40 against 35 for Customer.io.
Do companies use both Customer.io and OneSignal?
Yes. 1 company uses both on usedby, including Capacity.
Who uses Customer.io?
35 companies on usedby, each with the public page that shows it. See who uses Customer.io.
Who uses OneSignal?
40 companies on usedby, each with the public page that shows it. See who uses OneSignal.
How does usedby count customers?
A company counts when a public page shows it: a vendor's customer page, a case study, a press release or a job post, most saved with a dated capture. Every line is a customer, at one of four proof levels: confirmed, declared by the company itself, observed or signal (a job post, the weakest). A company counts as using both tools when it has a line on each, at any level; the list shows the strongest proofs first and marks job posts.