# Compare Klaviyo vs Thunderbird 2026 | Capterra

> Unsure of what to choose? Check Capterra to compare Klaviyo and Thunderbird based on pricing, features, product details, and verified reviews.

Source: https://www.capterra.com/compare/156699-230507/Klaviyo-vs-Thunderbird

---

# Klaviyo vs Thunderbird Features and Cost Comparison

Last updated March 13th, 2026

Provider data verified by our Software Research team, and reviews  
moderated by our Reviews Verification team.[Learn more](https://www.capterra.com/our-story/)

Your comparison:

KlaviyoThunderbird2/4 selected

[Klaviyo](https://www.capterra.com/p/156699/Klaviyo/)[4.6 (524)](https://www.capterra.com/p/156699/Klaviyo/reviews/)

[Thunderbird](https://www.capterra.com/p/230507/Thunderbird/)[4.4 (156)](https://www.capterra.com/p/230507/Thunderbird/reviews/)

[## Klaviyo](https://www.capterra.com/p/156699/Klaviyo/)[4.6 (524)](https://www.capterra.com/p/156699/Klaviyo/reviews/)

Starting Price

$20.00/month

Value-for-Money

4.3

Functionality

4.6

Ease of Use

4.5

Customer Service

4.3

Reviews Sentiment

Based on [524 reviews](#user-reviews)

Positive

498

Neutral

20

Negative

6

[## Thunderbird](https://www.capterra.com/p/230507/Thunderbird/)[4.4 (156)](https://www.capterra.com/p/230507/Thunderbird/reviews/)

Starting Price

Contact vendor

Value-for-Money

4.7

Functionality

4.3

Ease of Use

4.3

Customer Service

3.7

Reviews Sentiment

Based on [156 reviews](#user-reviews)

Positive

135

Neutral

17

Negative

4

## Not a match? Find software alternatives tailored to your priorities.

These software suggestions are similar to those you’re currently comparing.

### Marketing 360

4.5 (1,132)

* * *

Starting Price

Contact vendor for pricing

Free Trial

Free Version

* * *

User rating

90%

of reviewers  
rated it above 4 stars

* * *

Highest Rated

### LiveAgent

4.7 (1,753)

* * *

Starting Price

$15.00

Per User,Per Month

Free Trial

Free Version

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User rating

97%

of reviewers  
rated it above 4 stars

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### Marketo Engage

4.3 (710)

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Starting Price

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Free Trial

Free Version

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User rating

87%

of reviewers  
rated it above 4 stars

* * *

### EmailOctopus

4.8 (653)

* * *

Starting Price

$9.00

Per Feature,Per Month

Free Trial

Free Version

* * *

User rating

97%

of reviewers  
rated it above 4 stars

* * *

## Summary

* * *

Key features rated by users

Features selected based on 11,552 reviews from email management software users.  
about the Fit Score methodology.

Fit Score methodology

Our Fit Score reflects how reviewers rate a product’s performance against a set of features reviewers rate as most important. A higher score indicates the product is rated better in delivering what reviewers most care about.

  

If the Fit Score is not shown for a specific product, that only means there are currently not enough relevant data points to develop a meaningful score. It does not indicate that the product should be excluded from further evaluation. Best for Methodology

\--%Fit

Missing features

Feature ratings

Mobile App

NA

Email Distribution

NA

Inbox Management

NA

Email Monitoring

NA

Access Controls/Permissions

NA

\--%Fit

Missing features

Feature ratings

Mobile App

5.0

Email Distribution

NA

Inbox Management

4.5

Email Monitoring

NA

Access Controls/Permissions

NA

User satisfaction

User satisfaction

4.6

User reviews[524](https://www.capterra.com/p/156699/Klaviyo/reviews/)

Ease of use

4.5

Functionality

4.6

Value for money

4.3

Customer support

4.3

User satisfaction

4.4

User reviews[156](https://www.capterra.com/p/230507/Thunderbird/reviews/)

Ease of use

4.3

Functionality

4.3

Value for money

4.7

Customer support

3.7

Price starts from

Price starts from

$20Usage Based, Per Month

-   Free version
-   Free trial

Price starts from

\--

-   Free version
-   Free trial

Best for

Best for

Klaviyo serves B2C businesses of all sizes with 400+ native integrations, including Shopify, WooCommerce, Magento, Salesforce Commerce Cloud, Square Online, Mindbody, and more.

Best for

Not provided by vendor

## User reviews

Pros & cons

LW

Lee W.

Owner

> "Easy ability to see how much money generated for each email sent, good visibility of who opened emails and who was active on the site and how long..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___7077455)

Dan J.

Lead Strategist, Designer

> "They've continued to add features to try and justify the costs, but it gets harder to keep up as a small business."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___7115526)

IS

Ilayda S.

Marketing Director

> "It’s improved email open rates and resulted in more sales as we can send our fashion customers targetted promotions and keep them engaged with new..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6783045)

Doga I.

Director

> "Some features are not available for every account/business."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___7096566)

VR

Verified Reviewer

Digital and Marketing senior specialist

> "During my time at Playmaker and Reper International, I’ve utilized Klaviyo to bridge the gap between complex data and personalized customer..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___7114621)

VR

Verified Reviewer

Marketing

> "The recent price increases have come unexpectedly where they now charge for x amount of profiles, this wasn't something we expected when we renewed..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6857226)

Elena D.

Marketing Manager

> "It provides a lot of emails templates and a lot of drag sections to quick launch a Email marketing campaign and also you could design workflows to..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6686651)

JF

Jonah F.

Manager of Product Development and Business Operations

> "We experienced issues with contacts being overwritten when multiple sign-ups/subscriptions came through the same form."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6234071)

Sam Z.

Director Of Marketing And DTC

> "Klaviyo remains the easiest way for marketers to easily segment, personalize, and create behavior based automations."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___7058703)

Joseph E.

Ecommerce and IT Manager

> "I don't like the pricing structure for a lot of it."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___7038090)

OC

Owen C.

MD

> "its huge amount of integrations with a range of ecommerce platforms, specifically in our case the tight integration with Shopify, helping us to..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6497002)

KC

Katie C.

Email Team LEad

> "Cost and pricing structure are not my favorite."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6813794)

Kennedy K.

freelancer

> "The thing I love is how powerful the tool is in terms of email marketing and how it can be easily integrated with big platforms such as Shopify and..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6689292)

ZP

Zenia P.

Marketing Coordinator

> "Also, it bills based on profiles, and takes ALL profiles from your Woocommerce account whether they're signed up for email or not. When I made..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___4873198)

RO

Ricki O.

Owner

> "Klaviyo's best features include: 1) creating targeted campaigns and automating email workflows 2) detailed insights into email performance to be..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6551659)

GD

Grant D.

Production and Product Line Manager formerly Marketing and Web Manager

> "A bit pricy and tiers and auto upgrades take a while to get used to"

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6572455)

VR

Verified Reviewer

Digital and Marketing senior specialist

> "Being Klaviyo certified, I’ve seen firsthand how their predictive analytics and behavioral "Flows" outperform basic newsletters."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___7114621)

Raphael F.

Head of Ecommerce

> "It's a bit abusive even though the service is great."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6860235)

KK

Kevin K.

Marketing Manager

> "The flow builder is powerful, flexible, and ideal for organizations that rely on data-driven automation."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___7045217)

VR

Verified Reviewer

Chief of Staff

> "The interface can feel dense at first."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6823065)

DANIEL V.

Consultor

> "I have several clients with whom I have implemented the tool and at least 40% of sales are thanks to the flows, registration pages and campaigns..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6483491)

AW

Adam W.

eCommerce

> "The import from mailchimp was a bit of a hassle, and the sync between Klaviyo and Shopify has some unexpected issues that crop up, but that's likely..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___4821411)

SO

Sophie O.

Head of ecommerce

> "More and more start-ups are launching complementary services to Klaviyo, such as Wax (Whatsapp solution) and Loyoly (loyalty program), so we've..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6728534)

Raphael F.

Head of Ecommerce

> "We didn't appreciate the drastic price increase last year in 2024."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6860235)

RO

Ricki O.

Owner

> "Its powerful segmentation and automation tools allow me to create highly targeted and personalized email campaigns."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6551659)

MV

Mariana V.

Social media lead

> "It is a little more expensive than other similar tools."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6810154)

VR

Verified Reviewer

Marketing

> "They host weekly webinars, which are usually worthwhile and useful for the team to attend to learn about email marketing best practices."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6857226)

SK

Sabri K.

does not refund money

> "We canceled a plan by mistake, they do not take it back and do not give refunds"

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6359313)

LE

Lindsey E.

Owner - Head Designer

> "I love the ease of connecting Klaviyo to my Shopify store and other apps."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___7090949)

LC

Lataysha C.

Owner

> "My overall experience has been difficult to where I’ve used it and gave up on understanding it."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6768547)

BJ

Brittany J.

Operations Manager

> "I like that it has so many features that are one or two clicks to implement, like the follow up email feature."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6778473)

KM

Kortney M.

Owner

> "The cost was getting high especially for a small list. And the support was not always available straight away"

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6665441)

AW

Angela W.

Graphic Designer

> "We’ve seen better engagement, stronger results, and feel much more confident in our marketing since using Klaviyo."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___7075018)

IA

Isaac A.

Student

> "The only bad thing I found about this tool was that as the number of subscribers increased, the cost of Klaviyo also increased considerably, which..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___4907836)

JV

Jeannie V.

Operations Manager

> "Klaviyo has got some major perks—think advanced segmentation, in-depth analytics, and automation that’s perfect for eCommerce."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6541060)

MB

Miriam B.

Administrator

> "It was pretty complicated to manage the email domain switch."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6752033)

Kennedy K.

freelancer

> "It has been the best which has helped me in my journey to e-commerce and selling online, thus bridging the gap between me and my customers."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6689292)

AS

Allison S.

Email Designer

> "It could take a while for the support team to understand what I was asking for help with."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6564905)

Samuel A.

Digital marketing manager

> "I enjoyed using Klaviyo especially for email marketing, it's easy integration with website to interact with signups makes a great option for me"

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6652553)

RR

Ricardo R.

Marketing

> "Can get expensive, especially if using old email lists."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6292703)

Doga I.

Director

> "Best email marketing platform for D2C ecommerce businesses."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___7096566)

GN

Gerald N.

Marketing

> "It's starting to get super expensive as our list grows."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6249682)

RG

Rob G.

CEO

> "good email campaigns with automation, easy to setup flows, integration with ecommerce stores worked well."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___7006781)

Bo K.

Customer Service Ambassador

> "Has lots of reporting and analytics features but customizing them are not so practical, high management might not see them appealing."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6019114)

JN

Joshua N.

Application Specialist

> "Especially during the tough times of retail trade we have found it very successful in assisting with our conversion and driving traffic into our..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6366295)

TA

Trevor A.

Owner

> "The lack of human response when you have an issue, while paying a premium price, makes us not want to recommend Klaviyo to any of our clients."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___5062600)

VR

Verified Reviewer

CEO

> "I've used it for multiple clients and it's a very powerful and reliable app. If you've got the budget - go for it. If you're on a tight budget -..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6621821)

KN

Kyle N.

Owner

> "It is a lot of work and their support is very limited."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6296706)

MK

Madhura K.

Marketing Strategist

> "It’s a very good integration and this AI was able to capture the essence of our branding very well in a couple tryouts."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6367231)

SR

Steve R.

Digital Producer

> "Klaviyo list management is also poor, and like some other platforms (seems to be a trend), Klaviyo gears the system towards pushing you to pay for..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___3934652)

SW

Simona W.

Head of marketing

> "For the structure our emails, Klaviyo has been an effective tool."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6862781)

SL

Simon L.

Manager

> "Pricing seems a little high compared to others"

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6281452)

JM

Javier M.

Project Manager

> "Flows are easy to create, user profiles are really complete with all the info on a specific contact (if you have an ecommerce integration active)"

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6504218)

Mariia S.

Cosmetic Selling Manager

> "Not being able simply to transfer the email list of customers from our customer service database"

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___4777891)

IA

Isaac A.

Student

> "In addition, thanks to its advanced segmentation system, I was able to reach my target audience precisely, obtaining a higher opening and engagement..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___4907836)

KV

Katya V.

Developer

> "We had to download a separate integration tool and were still unable to integrate the emails without the automatic double confirmation email (even..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___4159014)

CL

Carissa L.

Marketing and Sales Manager

> "I really like the ease of use with Klaviyo and how they are constantly updating and releasing new features like Ai components"

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6825703)

SR

Steve R.

Digital Producer

> "Basic requirements for flows are unnecessarily difficult to implement. When you contact Klaviyo support, staff gives information that contradicts..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___3934652)

Bo K.

Customer Service Ambassador

> "Klaviyo could be the best when it comes to behaviour based automations especially building customer profiles and targets the correct customers when..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6019114)

NA

Ndifon A.

Founder and CEO

> "It's a significant drawback, especially for small businesses or those with limited budgets."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6008250)

Bill L.

Vice President of Sales and Operations

> "We like how the data graphs."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___7089137)

VR

Verified Reviewer

Eigenaar

> "Klaviyo keeps deducting money from our creditcard"

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6133256)

TO

Tareq O.

Sales Engineer

> "The segmentation tools enable us to create custom lists effortlessly, resulting in targeted mailings and improved results."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___4737543)

John S.

Social Media Consultant

> "One potential downside of this platform is its pricing structure. While there is a free version of Klaviyo available, the more advanced features and..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___4607346)

MS

Megha S.

marketing automation specialist

> "Klaviyo is appreciated by users for its user-friendly interface, advanced segmentation capabilities, integrations with other tools, analytics, and..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___4788112)

MC

Maria C.

Sales Executive

> "It's frustrating when Klaviyo slows down and we have to start over from scratch after making edits, especially if the Email we're creating has a lot..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___4679341)

SL

Suzanne L.

Head of CRM

> "Great functionality for building automations"

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6839745)

Md R.

Graphics Designe

> "I don't like Klaviyo campaign system it's take some times"

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___4821612)

SB

Sam B.

E-Commerce Manager

> "It integrates with Shopify remarkably well, and creating workflows via Shopify is very easy."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6746071)

JP

Juliette P.

CEO

> "Klaviyo is a little expensive compared to sendinblue that we used before."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6007467)

IL

Isaac L.

Director of Sales and Business Development

> "Their company continually develops new products that help merchants achieve greater success."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6859213)

MO

Maria O.

Growth Hacking Analyst

> "It has some essential features in a small letter size which is complicated and complex to read; sometimes it isn't as intuitive as you would like it..."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___3685319)

MK

Madhura K.

Marketing Strategist

> "I love how Klaviyo not only focuses on triggered flows and campaigns but sms too."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6367231)

TB

Tanya B.

CRM Manager

> "You cannot add users to a list based on their engagement actions in a workflow."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___3547680)

SL

Suzanne L.

Head of CRM

> "Frequent platform updates bringing new and improved capabilities"

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6839745)

VR

Verified Reviewer

Owner

> "I didn't know anything about email marketing before using Klaviyo."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6043278)

NM

Natasha M.

Controller

> "Syncs to Shopify and has good reporting."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6824030)

Ben U.

CTO

> "a bit expensive if you dont know what your doing."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6060970)

VR

Verified Reviewer

Marketing

> "It's easy to use, and the ability to build lists and segments is useful and also user friendly."

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___6857226)

MH

Mia H.

Associate Manager Marketing

> "Sometimes it is hard to monitor campaigns when there are multiple going on at once"

[See full review](https://www.capterra.com/p/156699/Klaviyo/#Capterra___4462927)

[View Reviews](https://www.capterra.com/p/156699/Klaviyo/reviews/)

Leandro A.

Developer

> "I use it as my main email client , both for personal use and for work , it feels comfortable .Big plus that they don't spam you"

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___7054778)

SA

Sara A.

Engineer

> "The settings interface is a bit confusing; in the future 365 email accounts may have issues to works as Thunderbird does not..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___6357971)

SP

Stuart P.

Product Manager

> "I was using another free email client that would not let me use different ports for incoming and outgoing mail so when searching..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___6880981)

JMV

Jose Miguel V.

Adjunct Professor

> "Aesthetics and UI: For me, this is a big problem. While this is subjective, and the interface can be customized, when you open..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4842912)

Leandro A.

Developer

> "Also is open source and doesn't spam you"

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___7054778)

Brendan B.

Coach

> "I have had certain performance issues that I could not explain or fix."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___6799859)

Brendan B.

Coach

> "Free, open, power, highly customizable email client."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___6799859)

RK

Robert K.

drafting

> "some extensions have bugs like send later"

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___6737417)

JMV

Jose Miguel V.

Adjunct Professor

> "Right now I am using Thunderbird for all my personal emails, and the client has all you need to manage successfully all your..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4842912)

JF

Jamie F.

Lead Technician

> "I always when trying to select the top email accidentally click the column header and re-order the emails which is annoying,..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___5093745)

MK

Matt K.

Consultant

> "Even when I've had ten or more email addresses to manage for different clients, it's been up to the job and easy to use."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___6463718)

SA

Sara A.

Engineer

> "I don't like very much the menu, especially the settings section."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___6357971)

NP

Nicolas P.

IT Manager

> "Very simple to use but could be configurated to have lots of stuff"

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___6805419)

VR

Verified Reviewer

Operations Analyst

> "Lack of Cloud Integration: Thunderbird does not offer cloud integration, which may limit its usefulness for users who need to..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4565113)

Sunny K.

Marketing Manager

> "Additionally, it facilitates the management of multiple email inboxes in a single, convenient location, which can be quite..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#GetApp___6048711)

UA

Ubed A.

Verification expert

> "However, some users may find Thunderbird's user interface outdated compared to other modern email clients, and it may not..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4616069)

JM

Juan M.

SEO supervisor

> "The intuitive user interface makes navigation a breeze, and the seamless integration with my existing email accounts was a huge..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4981089)

VR

Verified Reviewer

Operations Analyst

> "Limited Mobile Support: Thunderbird does not have a dedicated mobile app, which may make it difficult for users to access their..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4565113)

DK

Dev K.

Design Engineer

> "This is a best-of-class, open source and Free Software desktop email client that works very well with all necessary email..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___6130553)

VR

Verified Reviewer

Operations Analyst

> "Limited Customer Support: Thunderbird is an open-source project, which means that customer support is limited and users may have..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4565113)

JMV

Jose Miguel V.

Adjunct Professor

> "Another great addition of the last years was the "Smart folders," making your multiple account inbox easier to visit and search."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4842912)

VR

Verified Reviewer

Operations Analyst

> "Complex User Interface: Some users may find Thunderbird's user interface to be complex and difficult to navigate, especially if..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4565113)

Sunny K.

Marketing Manager

> "I have set up multiple accounts in Thunderbird, making it convenient for me to receive emails in one place."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#GetApp___6048711)

JMV

Jose Miguel V.

Adjunct Professor

> "This one was my first problem after I switch from Microsoft Outlook."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4842912)

UA

Ubed A.

Verification expert

> "Security and privacy: Thunderbird includes features such as encryption, phishing protection, and spam filtering that enhance..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4616069)

Gustavo B.

Director

> "It does not offer any cloud based system that might allow the software to be used away from where it was installed and..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___3484995)

Hugo G.

Software developer and support

> "Overall pleased but I'll like to see it improved"

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___6805669)

James C.

Sales and Marketing

> "Sometimes I had difficulty and slowness to do more specific searches, using keywords that were in the body of the email."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___3444626)

VR

Verified Reviewer

Operations Analyst

> "Customizable: Thunderbird Mail is highly customizable, allowing users to personalize their email experience by choosing from a..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4565113)

VR

Verified Reviewer

DAM Expert

> "No support per email or phone."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___5001917)

MK

Matt K.

Consultant

> "It's been my go-to desktop email client for twenty years."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___6463718)

MT

Monica T.

Project Manager

> "Sometimes when there are a lot of emails coming in it gets stuck, and from time to time I need to delete some of the emails."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___3808513)

DM

Davide M.

Indie Game Developer

> "I've benn using Thunderbird for several years and have had an overall positive experience with the software. While there are..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___5081958)

JD

Jacob D.

Executive

> "Namely, half the time when you repond, the reply won't be shown automatically inline (for at least several minutes)."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___3513931)

Austin M.

Software Analyst

> "I think the most impactful thing about Thunderbird is the community that uses the software, making it evolve constantly and..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___5079584)

UA

Ubed A.

Verification expert

> "Lack of support: Thunderbird is maintained by a small community of developers, so users may not receive prompt support or..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4616069)

AR

Ari R.

CEO

> "nice interface;- calendar built in (very well thought out);- tabs for better viewing;- mail and calendar pane in one single..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4153313)

Robert M.

Freelancer

> "I do not know why they have separated outgoing server settings in another section from the account setting."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___3763863)

UA

Ubed A.

Verification expert

> "Additionally, Thunderbird's ability to manage multiple email accounts from different providers, including POP, IMAP, and..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4616069)

Robert M.

Freelancer

> "The search and filter are not very functional, and I could not find my desired result from it."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___3763863)

VR

Verified Reviewer

Consultant / developer

> "Thunderbird is full of features, customizable with addons and themeable."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4842831)

VR

Verified Reviewer

Operations Analyst

> "However, some users may find the user interface to be complex and the performance to be slow on older computers."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4565113)

UA

Ubed A.

Verification expert

> "Thunderbird offers a wide range of add-ons and extensions that allow users to customize the program according to their needs."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4616069)

DS

David S.

Tech Acct MGR

> "Setting up Microsoft exchange inside of Thunderbird is difficult if you do not know what you're doing there really is no work..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___3834541)

Sunny K.

Marketing Manager

> "It accommodates various mail types and allows for easy configuration."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#GetApp___6048711)

VR

Verified Reviewer

CEO

> "The calendar and all the addons can't compete with Google or other alternatives."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4580663)

UA

Ubed A.

Verification expert

> "Its free and open-source software status and cross-platform support also make it a popular choice for users across different..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4616069)

Gonzalo M.

Managing Director

> "Integrates less well into Windows than some alternatives."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___3712769)

JM

Juan M.

SEO supervisor

> "Thunderbird has truly revolutionized the way I manage my inbox, and I couldn't be more impressed."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4981089)

TB

Tanya B.

Technician

> "One thing i particullarly hated was the fact that the program was crashing on me from time to time."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4620389)

Mohamed E.

Customer Success Specialist

> "I receive all the important emails on this software, it saves a lot of time and gets me notified of any available vacancies."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4635676)

James C.

Sales and Marketing

> "I've had problems with the manager simply stopping working and having to restart."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___3444626)

VR

Verified Reviewer

DAM Expert

> "Of course, I like that it is open-source and free of costs. And I like Thunderbird Filelink."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___5001917)

JD

Jacob D.

Executive

> "However, this add-on comes with its own bunch of issues."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___3513931)

JM

Juan M.

SEO supervisor

> "From the moment I started using Thunderbird, it was evident that this tool was designed with productivity in mind."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4981089)

JD

Jacob D.

Executive

> "Thunderbird, from my experience, is incredibly slow and buggy."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___3513931)

SS

Shashi S.

Student

> "It has fewer features than outlook but as a University student, the software works fine for me because I don't need all those..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4473755)

AR

Ari R.

CEO

> "RAM memory is another con that I'd point out."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4153313)

UA

Ubed A.

Verification expert

> "Overall, Mozilla Thunderbird is a popular email client that provides a range of features and customization options."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4616069)

Robert M.

Freelancer

> "Maybe it is my mistake, So at least it is not user-friendly enough to learn and work with."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___3763863)

GS

Grant S.

Head of Sales

> "All the features but leaner, more stable & faster."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___6165374)

DP

Darian P.

Team Lead of Internal Tools

> "We don't use the calendar functionality because it constantly would not work for our users."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___3021391)

JMV

Jose Miguel V.

Adjunct Professor

> "Since I have been using Thunderbird, I never regret my switch from Outlook."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4842912)

VR

Verified Reviewer

Senior system engineer

> "Most generic features are commercialized which will tend other users to use different mail clients"

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___3431281)

SP

Shane P.

Security system engineer

> "I like the fact that Thunderbird was free and worked for the most part."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___6008627)

SP

Santosh P.

Digital Marketer

> "Iwas needing cloud access to mails and my webmail was not cutting it."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___3198853)

Petter K.

Parish Manager

> "I think the main thing I can say that I like about Thunderbird is that it is free."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___6193707)

AL

Ad L.

Director

> "It has a rather childish menu bar layout in black and white."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___3024426)

ML

Mark L.

Owner

> "A great way to use an email system that is very low cost and has the features and benfits you will need for many small business..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___3639522)

Bill B.

President

> "Another issue I have is with the built-in calendar. "

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___3258266)

Stanley M.

System Administrator

> "I love the new modern look that ships with Thunderbird and the support for dark theme."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4169265)

SP

Shawn P.

Owner

> "The UI is incredibly outdated."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___3394046)

VR

Verified Reviewer

Senior system engineer

> "I think if you want to sync your gmail,hotmail, yahoo mail with your local client, Thunderbird is one such mail client which..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___3431281)

AL

Ad L.

Director

> "The opening of tabs is something i personally do not like."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___3024426)

JJ

Jeet J.

Founder & CEO

> "Moreover, it also supports adding SMTP mail which is really helpful."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4053362)

Teya B.

Teacher: Digital Illustration

> "I find the interface very, very dated."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___3150330)

AR

Ari R.

CEO

> "I was delighted to start using this app when a coworker recommended it to me because I'd been trying to find something that was..."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___4153313)

AL

Ad L.

Director

> "Don't like the visual."

[See full review](https://www.capterra.com/p/230507/Thunderbird/#Capterra___3024426)

[View Reviews](https://www.capterra.com/p/230507/Thunderbird/reviews/)

## User interface

[Klaviyo](https://www.capterra.com/p/156699/Klaviyo/)

4.64 (524)

[Thunderbird](https://www.capterra.com/p/230507/Thunderbird/)

4.40 (156)

### Features

Do these products fit your needs?

Prioritize real-user-identified key features according to your needs to find your best fit.

\--% Fit

vs

\--% Fit

Access Controls/Permissions

207

Important

Activity Dashboard

150

Important

AI Copilot

120

Important

Klaviyo

Top features

23/47

-   Access Controls/Permissions
-   Activity Dashboard
-   AI Copilot
-   Alerts/Notifications
-   API
-   Archiving & Retention
-   Autoresponders
-   Campaign Analytics
-   Campaign Management
-   Canned Responses
-   Chat/Messaging
-   Collaboration Tools
-   Contact Management
-   Customer Segmentation
-   Customizable Fields
-   Customizable Forms
-   Customizable Templates
-   Data Recovery
-   Drag & Drop
-   Email Distribution
-   Email Marketing
-   Email Monitoring
-   Email Templates
-   Email Tracking
-   Generative AI
-   Inbox Management
-   Mobile App
-   Multiple User Accounts
-   Prioritization
-   Process/Workflow Automation
-   Queue Management
-   Real-Time Analytics
-   Real-Time Monitoring
-   Real-Time Reporting
-   Reporting/Analytics
-   Response Management
-   Routing
-   Search/Filter
-   Shared Inboxes
-   Signature Management
-   Social Media Integration
-   Spam Blocker
-   Support Ticket Management
-   Tagging
-   Third-Party Integrations
-   Whitelisting/Blacklisting
-   Workflow Management

[See all features](https://www.capterra.com/p/156699/Klaviyo/#features)

Thunderbird

12/47

-   Access Controls/Permissions
-   Activity Dashboard
-   AI Copilot
-   Alerts/Notifications
-   API
-   Archiving & Retention
-   Autoresponders
-   Campaign Analytics
-   Campaign Management
-   Canned Responses
-   Chat/Messaging
-   Collaboration Tools
-   Contact Management
-   Customer Segmentation
-   Customizable Fields
-   Customizable Forms
-   Customizable Templates
-   Data Recovery
-   Drag & Drop
-   Email Distribution
-   Email Marketing
-   Email Monitoring
-   Email Templates
-   Email Tracking
-   Generative AI
-   Inbox Management
-   Mobile App
-   Multiple User Accounts
-   Prioritization
-   Process/Workflow Automation
-   Queue Management
-   Real-Time Analytics
-   Real-Time Monitoring
-   Real-Time Reporting
-   Reporting/Analytics
-   Response Management
-   Routing
-   Search/Filter
-   Shared Inboxes
-   Signature Management
-   Social Media Integration
-   Spam Blocker
-   Support Ticket Management
-   Tagging
-   Third-Party Integrations
-   Whitelisting/Blacklisting
-   Workflow Management

[See all features](https://www.capterra.com/p/230507/Thunderbird/#features)

### Recognition

No recognitions have been awarded to Klaviyo

No recognitions have been awarded to Thunderbird

### Deployment & support

Klaviyo

Deployment

-   Cloud, SaaS, Web-Based
-   Desktop Mac
-   Desktop Windows
-   Desktop Linux
-   On-Premise Windows
-   On-Premise Linux
-   Desktop Chromebook
-   Mobile Android
-   Mobile iPhone
-   Mobile iPad

Support

-   Email/Help Desk
-   FAQs/Forum
-   Knowledge Base
-   Phone Support
-   24/7 (Live rep)
-   Chat

Training

-   In Person
-   Live Online
-   Webinars
-   Documentation
-   Videos

Thunderbird

Deployment

-   Cloud, SaaS, Web-Based
-   Desktop Mac
-   Desktop Windows
-   Desktop Linux
-   On-Premise Windows
-   On-Premise Linux
-   Desktop Chromebook
-   Mobile Android
-   Mobile iPhone
-   Mobile iPad

Support

-   Email/Help Desk
-   FAQs/Forum
-   Knowledge Base
-   Phone Support
-   24/7 (Live rep)
-   Chat

Training

-   In Person
-   Live Online
-   Webinars
-   Documentation
-   Videos

### Company Details

Klaviyo

-   By Klaviyo
-   Located in United States
-   Founded in 2012

Thunderbird

-   By Mozilla
-   Located in United States
-   Founded in

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4.4

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[Klaviyo](https://www.capterra.com/p/156699/Klaviyo/)[4.64 (524)](https://www.capterra.com/p/156699/Klaviyo/reviews/)

vs

[Constant Contact](https://www.capterra.com/p/31898/Constant-Contact/)[4.34 (2,911)](https://www.capterra.com/p/31898/Constant-Contact/reviews/)

$20/month

Price

$12/month

4.6

Features

4.2

4.5

Ease of Use

4.3

[View full comparison](https://www.capterra.com/compare/31898-156699/Constant-Contact-vs-Klaviyo)

[Thunderbird](https://www.capterra.com/p/230507/Thunderbird/)[4.40 (156)](https://www.capterra.com/p/230507/Thunderbird/reviews/)

vs

[Brevo](https://www.capterra.com/p/132996/brevo/)[4.62 (3,406)](https://www.capterra.com/p/132996/brevo/reviews/)

$0

Price

$9/month

4.3

Features

4.5

4.3

Ease of Use

4.6

[View full comparison](https://www.capterra.com/compare/132996-230507/brevo-vs-Thunderbird)