ZeroBounce: most-reported complaints
Automated analysis of 279 public Trustpilot reviews published 2017-09-22 to 2026-07-19. TrustScore 4.8 from 2,127 total reviews — see the Trustpilot page. Quick answer: is ZeroBounce legit? Issues below reflect what reviewers reported, not findings of wrongdoing.
Reviewers most often report excessive contact attempts, with 20 complaints citing too many emails and calls in a short period. Support issues are the second most frequent concern, accounting for 13 reports where users describe unhelpful assistance or account blocks. Other notable complaints include faulty product performance (8 reports) and services not matching their description (6 reports).
How to reach ZeroBounce
These are the contact details ZeroBounce publishes on its Trustpilot profile, as of our last check on 2026-09-24 — phone +18885009521, email [email protected], address 10 E Yanonali St, Santa Barbara, 93101, US.
The company claimed its Trustpilot profile on 2017-09-16, uses Trustpilot’s paid features, and last replied to a negative review on 2026-06-17. Trustpilot ranks it 82 of 254 in Business to Business Service. We last checked this profile on 2026-09-24 and found 1 new review. These are facts Trustpilot publishes about the profile, as of our last harvest.
Elsewhere: 5★ on Google (4 reviews)
TrustScore over time
4.8 → 4.8 across 3 census measurements since 2026-08-17. Our own record, independent of Trustpilot’s display.
Severity: 10% of this company’s 63 graded complaints were classified as severe (money lost, an essential service cut off, or a problem unresolved for months). See the harm index.
What their policy promises
guarantee: lower bounce rate and improve email deliverability
“we guarantee to lower your bounce rate and improve email deliverability.”
guarantee: eliminate spam complaints
“we'll determine how many spam complaints you can expect to eliminate using ZeroBounce email validation.”
guarantee: quickly reduce spam complaints
“Email validation can quickly reduce your spam complaints”
guarantee: reduce spam complaints by as much as 30%
“we'll let you know to take action. These figures are based on ZeroBounce's ability to reduce your spam complaints by as much as 30% with the help of email validation.”
Quoted verbatim from the company’s own published policy (source page); complaint counts are census classifications. As of 2026-09-17.
Policy-page monitoring
We monitor this company’s published policy page for changes. 2 changes detected since we started watching on 2026-09-01:
- 2026-09-15: +10/-0 lines; added: Spam complaint rate is the percentage of sent emails that users report as spam. You can find your spam complaint rate by checking your email campaign reports after your campaign is sent. | The average recommended spam complaint rate is 0.1% or 1 in 1,000 emails. This is an ideal, safe threshold, tho (snapshot)
- 2026-09-08: +1/-0 lines; added: AI-Managed Mailboxes (snapshot)
Automated change detection on the company’s own published policy page — a record of when the page changed, not a judgement on what changed.
Measured reply time: across 84 negative reviews that received a public reply, the median wait was 0.3 days — the company profile reports an average of 21 days. The two are measured differently: ours counts only replies we captured to negative reviews.
Reply quality: of 84 company replies to negative reviews analysed, 30% engaged with the specific problem and 65% were generic templates.
Review provenance: 148 company-invited reviews in the recent window average 4.88★, while 53 organic (uninvited) reviews average 4.47★.
77% of its 175 recent 5★ reviews came from accounts that had written only that one review when we captured it (the median across companies is about 39%). A high share is a reason to look closer, not evidence of fake reviews.
Sector benchmark: other makes up 32% of this company’s complaints vs a 22% median across 249 ranked companies in its sector.
Review velocity: 128 of this company’s 2,127 Trustpilot reviews (6%) were written in the last 12 months.
What are the most common complaints about ZeroBounce?
Other
20 reports · 32% of complaintsfalling“Got 3 mails and 3 calls in less than a week from Zerobouce, that's a little too much.”
The company replied on 2021-12-17: “Hi, Guillaume Thank you very much for sharing your feedback! We apologize for the multiple emails and calls. As for your results, we reached out to you and hope our answer was satisfactory. Please…”
Our classifier read this reply as a template response.
1 reader marked this review helpful on Trustpilot.
“i can see that validated emails are getting bounced.”
The company replied on 2019-09-25: “Thank you for letting us know -- and for reviewing us! We can take a look at your bounces and see what's causing them. Best, Team ZeroBounce”
Our classifier read this reply as a substantive response.
1 reader marked this review helpful on Trustpilot.
“only 50% of my email list are valid, every time is 50%”
The company replied on 2025-08-25: “We really appreciate you taking the time to share your experience. We understand how concerning it can feel if only half of your list comes back as valid. Every list is unique, and there can be…”
Our classifier read this reply as a template response.
Support unhelpful
13 reports · 21% of complaintssteady“Now they blocked my account and I cannot even use the remaining credits I had.”
2 readers marked this review helpful on Trustpilot.
“customer service was not too helpful at all.”
The company replied on 2018-04-29: “Ed, we are sorry to hear that. Let us reach out to you, we would actually love to help! Best, Team ZeroBounce”
Our classifier read this reply as a template response.
1 reader marked this review helpful on Trustpilot.
“Every reply to and from their support team was from a different person.”
The company replied on 2026-05-27: “Hello, Mr. Watterson, Thank you for sharing your feedback. We're sorry the process felt confusing and frustrating. You’re absolutely right that a more consistent experience matters, and we fell short…”
Our classifier read this reply as a substantive response.
It promised: to make contact.
Faulty product
8 reports · 13% of complaintsfalling“Now they blocked my account and I cannot even use the remaining credits I had.”
2 readers marked this review helpful on Trustpilot.
“I HAVE HAD 10% BOUNCE RATE WITH THESE MFfucckers!”
The company replied on 2023-09-25: “Hi, Constantine We're sorry for the issues you're experiencing. Our team is looking at it with all hands on deck to fully determine the cause. It looks like some of the bounces were due to the…”
Our classifier read this reply as a substantive response.
It promised: to escalate.
1 reader marked this review helpful on Trustpilot.
“Several times even after running database through Zero bounce, we receive a lot of hard and soft bounces on the database.”
The company replied on 2019-06-07: “Your feedback means a lot to us, thank you! We'll pass your observations on to our engineers. Best, Team ZeroBounce”
Our classifier read this reply as a template response.
1 reader marked this review helpful on Trustpilot.
Not as described
6 reports · 10% of complaintsfalling“got in my opinion a bit to high bounce rate on an email blast after using ZeroBounce”
The company replied on 2019-09-13: “Michael, thank you for reviewing us and for letting us know about this issue. We'll do our best to fix it. Team ZeroBounce”
Our classifier read this reply as a substantive response.
It promised: to make contact.
1 reader marked this review helpful on Trustpilot.
“many of them were actually valid, i checked all of them and many were valid.”
The company replied on 2019-09-12: “Hi, Thanks for letting us know about your experience. ZeroBounce offers you different download options, so you can get exactly what you want. Here are the steps:…”
Our classifier read this reply as a substantive response.
It promised: to make contact.
1 reader marked this review helpful on Trustpilot.
“It popped up that it was an abuse email. This is an email address I’ve been using for years”
The company replied on 2024-06-20: “Jo, Thanks for your feedback and we understand why you might question your own email showing up as abuse. Hopefully some explanation around that label will provide more context. "Abuse" is a label…”
Our classifier read this reply as a substantive response.
Account/app problems
5 reports · 8% of complaintsrising since 2025-02“zerobounce closed my account with $930 = 300000 credits without warning or reason.”
2 readers marked this review helpful on Trustpilot.
“Now they blocked my account and I cannot even use the remaining credits I had.”
2 readers marked this review helpful on Trustpilot.
“They prevented my registration and wouldn't tell me why”
The company replied on 2023-06-20: “Hi, Lidia Thank you for bringing this to our attention. We're sorry for your experience and for not being more clear about the reason why your account registration was blocked. Your personal…”
Our classifier read this reply as a substantive response.
It promised: to make contact.
1 reader marked this review helpful on Trustpilot.
Misleading pricing
4 reports · 6% of complaintsrising since 2025-02“The company gets you to sign up promising 100 free credits, but then only gives you one (yes 1)”
The company replied on 2025-02-07: “Hi, Syd We’re sorry for any confusion regarding our free credit system and appreciate your feedback. Please allow us to clarify how it works: - For free email accounts (like Gmail, Yahoo, etc.), we…”
Our classifier read this reply as a substantive response.
It promised: to make contact.
1 reader marked this review helpful on Trustpilot.
“Disappointed it says free email verification tool when it's not free. Very misleading”
The company replied on 2025-01-14: “Hi, Ayla We're sorry to hear you're disappointed, but please know that ZeroBounce has a Freemium package that allows you to use most of our tools for free. This package includes: 100 email…”
Our classifier read this reply as a substantive response.
It promised: to make contact.
“They claim to offer a lot of features they don't even have”
The company replied on 2018-02-07: “Hello, Mrs. Peterson We are so sorry to hear you were disappointed with our service. We want to learn more about what happened, so we will get in touch with you soon. Thank you. Team ZeroBounce”
Our classifier read this reply as a template response.
Compare ZeroBounce with…
Method: reviews are classified into a fixed complaint taxonomy by an automated reader; every category shown is backed by at least two verbatim quotes from distinct reviews. Trends are computed from dated review counts only. Negative reviews are deliberately over-sampled for evidence depth; headline percentages use an unbiased recent sample only. Report updated 2026-09-07.