What are the best pay-as-you-go email validation tools?

11 Marketer opinions 4 Expert opinions 3 Technical articles 6 Resources

Summary

Multiple email validation tools offer pay-as-you-go options. Kickbox is a frequently mentioned solution with a penny-per-verified-address model and volume discounts, known for cleaning email lists effectively. ZeroBounce and BouncerApp offer easy sign-up and per-email payment. Other providers include NeverBounce, Hunter.io, Debounce.io, Email Hippo, EmailListVerify, CaptainVerify, and Emailable, each focusing on accuracy, integrations, and features like syntax checks and spam trap detection. Mailgun and Abstract API also offer pay-as-you-go models, with included free tiers, focusing on deliverability and detailed validation. A Reddit user recommends ZeroBounce. Word to the Wise advises considering ESP-provided validation, noting varying definitions of 'invalid'.

Key findings

Kickbox Popular: Kickbox is a frequently recommended pay-as-you-go email validation tool.
ZeroBounce & BouncerApp Easy Start: ZeroBounce and BouncerApp offer easy signup and per-email payment.
Multiple Providers: A wide variety of providers offer pay-as-you-go email validation services.
Feature Variety: Various features are offered, including syntax checks, spam trap detection, and deliverability focus.
ESP Integration: Many ESPs offer built-in validation services, but definitions of 'invalid' may vary.
Free Tiers: Mailgun and Abstract API both offer free tiers.
Positive Reviews: ZeroBounce has positive reviews from users.

Key considerations

Pricing Models: Compare pricing models, including per-email costs, volume discounts, and credit systems.
Feature Needs: Identify the specific features needed (e.g., syntax checks, spam trap detection) to align with validation goals.
ESP Validation: Evaluate ESP-provided validation tools, understanding their specific criteria for identifying invalid addresses.
Accuracy & Integration: Prioritize services known for accuracy and seamless integration with existing marketing platforms.
Free Tier Limitations: Evaluate limitations of free tiers when using Mailgun or AbstractAPI

What email marketers say
11Marketer opinions

Several email validation tools offer pay-as-you-go pricing models. ZeroBounce and BouncerApp are popular choices, requiring only a signup to begin paying per email validated. NeverBounce, Hunter.io, Debounce.io, Email Hippo, EmailListVerify, CaptainVerify, and Emailable all offer similar services, focusing on accuracy, integrations, and features like syntax checks, spam trap detection, and comprehensive reporting to improve sender reputation and deliverability. ZeroBounce is specifically recommended by one Reddit user. ESPs may offer email validation tools as part of their core offering.

Key opinions

Multiple Options: Numerous email validation services offer pay-as-you-go pricing.
Easy Start: Some services, like ZeroBounce and BouncerApp, require only a signup to begin.
Feature Variety: Different services offer various features, including email scoring, abuse email detection, syntax checks, and spam trap detection.
Positive Reviews: ZeroBounce has received positive feedback from users.
ESP Integration: Some Email Service Providers (ESPs) offer validation tools as part of their core service.

Key considerations

Feature Set: Consider the specific features offered by each service and how they align with your needs.
Accuracy: Prioritize services known for their high accuracy in identifying invalid email addresses.
Integration: Check whether the service integrates seamlessly with your existing email marketing platform.
Pricing: Compare the pay-as-you-go pricing models of different services to find the most cost-effective option.
ESPs: Check if your ESP offers a validation service - as the definitions of invalid may vary.

Marketer view

Email marketer from Emailable.com states that they offer an easy to use pay as you go payment system for simple email address validation.

September 2022 - Emailable.com

Marketer view

Marketer from Email Geeks shares that Zero Bounce & BouncerApp just require a signup email, then you can pay per email.

August 2022 - Email Geeks

Marketer view

Email marketer from NeverBounce.com shares that they offer pay-as-you-go email verification with no monthly fees, focusing on accuracy and integrations.

August 2022 - NeverBounce.com

Marketer view

Email marketer from EmailListVerify.com answers by promoting their email list verification service that operates on a pay-as-you-go system. They are focusing on removing invalid and harmful email addresses, helping to improve sender reputation.

May 2021 - EmailListVerify.com

Marketer view

Email marketer from CaptainVerify.com highlights their pay-as-you-go email validation service, which includes syntax validation, domain validation, and spam trap detection.

January 2024 - CaptainVerify.com

Marketer view

Email marketer from Usebouncer.com shares that they offer a pay-as-you-go option with a focus on deliverability and accuracy, including features like toxicity check and deliverability kit.

April 2023 - Usebouncer.com

Marketer view

Email marketer from Debounce.io highlights their pay-as-you-go email validation service, emphasizing features like syntax check, domain validation, and spam trap detection.

May 2023 - Debounce.io

Marketer view

Email marketer from ZeroBounce.net explains their pay-as-you-go plan, highlighting features like email scoring, abuse email detection, and comprehensive reporting.

June 2023 - ZeroBounce.net

Marketer view

Email marketer from Hunter.io describes their email verification service that offers pay-as-you-go options. This allows the verification of individual email addresses or bulk lists without a subscription, focusing on accuracy.

March 2022 - Hunter.io

Marketer view

Email marketer from Emailhippo.com shares that they offer a 'Credits' pricing model which can be used on a pay as you go basis. They have a range of validation tools from Syntax validation to spam traps.

October 2023 - Emailhippo.com

Marketer view

Email marketer from Reddit answers by saying 'I have had good experiences with ZeroBounce and their pay as you go plan, I would recommend'

March 2022 - Reddit

What the experts say
4Expert opinions

Kickbox is mentioned as a pay-as-you-go email validation tool, offering a penny-per-verified-address pricing model and volume discounts. It's noted for its effectiveness in cleaning email lists, as demonstrated by its use in reviving a jazz club's newsletter. Word to the Wise highlights that many ESPs offer email validation as part of their services, but it is important to understand each provider's definition of an 'invalid' address.

Key opinions

Kickbox Mentioned: Kickbox is repeatedly recommended as a pay-as-you-go option.
Practical Use: Real-world experience confirms Kickbox's value in cleaning email lists.
ESP Considerations: ESPs often include validation tools, but the definition of 'invalid' can vary.

Key considerations

Pricing: Consider Kickbox's penny-per-address pricing and potential volume discounts.
Definition of Invalid: Understand how each validation service defines 'invalid' addresses.
ESP Options: Evaluate whether your ESP provides sufficient validation services.

Expert view

Expert from Word to the Wise explains that many ESPs provide email validation tools as part of their service and recommends understanding how each one defines 'invalid' before use, as some are more aggressive than others. There is no specific URL available as this is based on general content, not a specific tool.

July 2023 - Word to the Wise

Expert view

Expert from Email Geeks shares experience using Kickbox to clean a jazz club email newsletter, highlighting its usefulness in removing bad addresses.

November 2023 - Email Geeks

Expert view

Expert from Email Geeks shares that Kickbox has a penny-per-verified-address pricing model.

July 2024 - Email Geeks

Expert view

Expert from Email Geeks recommends Kickbox for its pay-as-you-go pricing and volume discounts.

August 2024 - Email Geeks

What the documentation says
3Technical articles

Kickbox, Mailgun, and Abstract API all offer pay-as-you-go email validation services. Kickbox's documentation highlights its flexible credit system. Mailgun emphasizes improved deliverability and reduced bounce rates with usage-based pricing and a free tier. Abstract API also offers a free tier followed by flexible pay-as-you-go options, detailing features like syntax validation, disposable email detection, and deliverability checks.

Key findings

Pay-as-you-go options: All three services offer pay-as-you-go email validation pricing models.
Free tiers: Mailgun and Abstract API provide free tiers for initial usage.
Deliverability focus: Mailgun emphasizes improved deliverability and reduced bounce rates.
Feature details: Abstract API details features such as syntax validation and disposable email detection.

Key considerations

Pricing structure: Compare the pricing models of Kickbox, Mailgun, and Abstract API to determine the most cost-effective option for your needs.
Free tier limitations: Evaluate the limitations of the free tiers offered by Mailgun and Abstract API.
Feature requirements: Determine which features (e.g., syntax validation, disposable email detection) are most important for your email validation strategy and choose a service that provides them.
Deliverability needs: If deliverability is a primary concern, consider Mailgun's emphasis on reduced bounce rates.

Technical article

Documentation from Abstractapi.com explains the Abstract API email validation service, with a free tier, and then flexible pay as you go options. It details features like syntax validation, disposable email detection, and deliverability checks.

May 2023 - Abstractapi.com

Technical article

Documentation from Mailgun.com explains Mailgun's address validation service, emphasizing that it helps reduce bounce rates and improve deliverability; pricing is usage based, with included free tiers.

September 2024 - Mailgun.com

Technical article

Documentation from Kickbox.com states that Kickbox offers flexible, pay-as-you-go pricing for email verification, allowing users to pay only for the credits they need.

April 2024 - Kickbox.com

Kickbox: Email Address Verification Service

Verify your email list in minutes, or integrate real-time email verification into your app with our API. Over 26 billion emails verified. Get started for free.

Kickbox

9 Best Email Verification Tools in 2025 (Tested & Reviewed)

Sending emails to unverified addresses = not reaching your target audience. Here are the best verification tools to ensure you open new business opportunities.

lemlist Blog

6 Best Email Verification Tools in 2025 [Hand Picked]

We tested several email verification tools and picked 5 great options worth giving a try. Click here to learn more.

Mailtrap

The 10 Best Pay-As-You-Go User Testing Tools

Explore the top pay-as-you-go user testing tools for flexible, on-demand usability insights without long-term commitments. 1. Userbrain 2...

Userbrain Blog

Best Email Verification Services of 2025: Prices And Features

We covered multiple parameters: price, verification methods, APIs, browser extensions, and additional tools. Here's what email verifiers are the best.

Snovio Labs