Kustomer vs Sierra: who uses which
Customers, public proof and the companies that use both.
On usedby, 32 companies use Kustomer and 50 use Sierra. No company is listed with both yet. Kustomer leads among the E-commerce & D2C companies on usedby that use either tool, Sierra among the Fintech & Payments companies.Latest check Oct 7, 2026: 82 of 82 public lines checked. Counts include every proof level, job-post signals included. Companies named on both have a confirmed or observed line on each side.
Who uses Kustomer, Sierra, or both
Every company with a public proof for at least one of the two tools.
32
use only Kustomer
0
companies use both
50
use only Sierra
32 companies use only Kustomer, 50 use only Sierra and 0 use both, out of the 82 companies on usedby that use at least one of them.
Where it lands
Newest customers
We have not started tracking changes for Kustomer yet.
Where it lands
Newest customers
Who uses both
Companies with a confirmed or observed line on both tools.
By industry
Which tool the companies on usedby use, by industry. Shares of the companies on usedby that use Kustomer, Sierra or both: a share of the companies on usedby, not of the market.
Kustomer onlyBothSierra only
More common with Kustomer
- E-commerce & D2C9 of the 10 E-commerce & D2C companies on usedby that use either tool use Kustomer.
- Fashion & Apparel6 of the 6 Fashion & Apparel companies on usedby that use either tool use Kustomer.
More common with Sierra
- Fintech & Payments5 of the 6 Fintech & Payments companies on usedby that use either tool use Sierra.
Source: confirmed and observed usedby lines. Job-post signals, the weakest proof level, are left out of these shares.
Side by side
Facts from our data and from each vendor's public pages. Each line says where it comes from.
KustomerSierraWhat customers report
Results as the vendor or the customer published them, with the source and the date.
Kustomer
chat grew from 36% to 66% of all inbound volume in under 9 months
MeUndies
Vendor case study, kustomer.com, captured Oct 3, 2026
How Coterie Baby uses Kustomer
Coterie Baby
Vendor case study, kustomer.com, captured Oct 3, 2026
Sierra
Nearly 1,000 hours per month returned to exception handling and high-value work
RunBuggy
Vendor case study, sierra.ai, published Feb 3, 2026
Questions about Kustomer and Sierra
Which is used more, Kustomer or Sierra?
Sierra has more customers on usedby: 50 against 32 for Kustomer. Kustomer leads among the E-commerce & D2C companies on usedby that use either tool, Sierra among the Fintech & Payments companies.
Do companies use both Kustomer and Sierra?
usedby has not found a company with a confirmed or observed line on both Kustomer and Sierra yet.
Who uses Kustomer?
32 companies on usedby, each with the public page that shows it. See who uses Kustomer.
Who uses Sierra?
50 companies on usedby, each with the public page that shows it. See who uses Sierra.
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 three proof levels: confirmed, observed or signal (a job post, the weakest). A company is named as using both tools when its lines on both are confirmed or observed.