mailboxlayer API
NeverBounce
Kickbox
ZeroBounce
Email Checker
Email List Verify
Email Verifier
emailvalidation.io
Omnivery
SendGrid Email API
Sparkpost
Postmark
Mailgun
Mailjet
Mandrill
Amazon SES
Omnivery is a security-first transactional email platform for teams whose password resets, 2FA codes, receipts, and confirmations have to arrive โ in the inbox, on time. It provides both an SMTP relay and a REST API natively compatible with the SendGrid v3, Mailgun v3, and SparkPost v1 schemas, so most integrations migrate with no code changes.
Its foundations are unusual for the category. Omnivery runs on 100% owned infrastructure โ no third-party cloud โ and enforces strict sender vetting: every customer and every sending domain is reviewed before activation, there are no free plans, and the result is a clean shared-IP neighbourhood that outperforms dedicated IPs for most senders. Deliverability is handled by senior human analysts who contact you before issues become incidents, not by automated alerts.
On compliance, Omnivery is certified to ISO 27001, ISO 27701, and HIPAA โ a combination unique among transactional providers โ never stores message content, and offers data residency in the EU or US. Native security features include phishing protection, email journaling for litigation defence, and a Bot Detection API that identifies non-human interactions.
Heritage: 18+ years of deliverability expertise originating with Mailkit (2006, Czech Republic).
mailboxlayer API OmniveryOmnivery's answer:
Omnivery's answer:
Omnivery closes the gaps the major providers leave. Against SendGrid, Mailgun, and Amazon SES you get 100% owned infrastructure (no third-party cloud), the ISO 27001 / 27701 / HIPAA trio, native bot detection, and deliverability run by senior human analysts rather than automated alerts โ a combination none of them offer together. Migration is low-risk: the REST API is natively compatible with SendGrid v3, Mailgun v3, and SparkPost v1, so most integrations move with a credential swap, and one-click migration carries over suppression lists, bounces, and unsubscribes. Kiwi switched in 45 minutes and saw a 17% click-rate improvement. And with data residency available in both the EU and US, teams with regional compliance requirements are covered either way.
Omnivery's answer:
Omnivery runs entirely on its own infrastructure โ no third-party cloud provider โ built security-first with support for multiple geographic data-storage regions. Sending is delivered through a high-performance mail transfer agent exposed as both an SMTP relay and a REST API that is natively compatible with the SendGrid v3, Mailgun v3, and SparkPost v1 schemas, with real-time webhooks for delivery events. The Bot Detection API is powered by 20+ proprietary datasets built over 8+ years, combining IP reputation, user-agent analysis, behavioural pattern matching, and honeypot data.
Omnivery's answer:
Omnivery grew out of Mailkit, an email platform founded in the Czech Republic in 2006 that became known for deliverability โ "the ones who know how to deliver." Over the years, customers kept asking to use that sending infrastructure directly as an SMTP and API service. Founder and CEO Jakub Olexa saw that most sending services shared the same weakness โ loose abuse controls and weak privacy enforcement dragging down everyone's reputation and deliverability โ so Omnivery was built on the opposite principle: strict sender vetting, no free plans, owned infrastructure, and compliance first. The company was founded in 2021 and the platform launched in May 2022, carrying 18+ years of deliverability heritage.
Omnivery's answer:
Omnivery is a transactional email platform that runs on 100% owned infrastructure โ no third-party cloud โ and admits only vetted senders, so every customer sends from a clean IP neighbourhood rather than a shared pool full of unknown accounts. Three things set it apart from SendGrid, Mailgun, and Amazon SES: it is certified to ISO 27001, ISO 27701, and HIPAA together (a combination no other major transactional provider holds), it never stores message content, and it includes a Bot Detection API that flags security-scanner clicks, Apple MPP opens, and botnet fraud. Deliverability is handled by senior human analysts who reach out before problems become incidents โ not by automated alerts.
Omnivery's answer:
Omnivery is built for teams that treat email as mission-critical infrastructure and can't afford a password reset, 2FA code, receipt, or booking confirmation to arrive late or land in spam. In practice that means SaaS and product teams, e-commerce and marketplaces, travel and booking platforms, and regulated industries โ financial services, insurance, and healthcare (Omnivery is HIPAA-certified, with BAAs available). It's a particularly strong fit for regulated and privacy-sensitive teams that need compliance enforced at the infrastructure level โ with data residency available in the EU or US โ and for utilities, banks, and public-sector bodies running legacy systems that can send via SMTP but can't be rebuilt around a REST API.
I've been using Omnivery for a little over a year now, and the platform has continued to evolve in ways that have helped take our email program to the next level. One of the biggest differentiators is its ability to identify and report true human clicks while filtering out bot activityโsomething I haven't seen by other providers.
Beyond the technology, the partnership has been outstanding. Whenever we've needed enhancements or had new ideas, the Omnivery team has been open to feedback, collaborative, and quick to work with us on solutions. Having an additional set of experienced eyes reviewing our program week after week has been incredibly valuable.
I truly appreciate the partnership and look forward to continuing to work with Omnivery for years to come.
Based on our record, mailboxlayer API seems to be more popular. It has been mentiond 5 times since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
I've found a few "free" APIs which tell you if the email address exists or not, they have a free tier for certain amount of queries. Try https://mailboxlayer.com and https://www.zerobounce.net. Source: almost 4 years ago
What I mean by valid is whether it is deliverable or not. Like this https://mailboxlayer.com/. Source: almost 4 years ago
In Inspector we use the mailboxlayer.com API to validate emails. The service is also able to detect fake email addresses, temporary addresses, and the actual existence of an email address using MX-Records and SMTP. - Source: dev.to / over 4 years ago
You can look into APIs ( example https://mailboxlayer.com/ ) they provide info whether email is from a disposable domain. Source: almost 5 years ago
Mailboxlayer.com โ Email validation and verification JSON API for developers. 1,000 free API requests/month. - Source: dev.to / almost 5 years ago
NeverBounce - Real-time email verification and cleaning to ensure emails never bounce.
SendGrid Email API - You can use SendGrid via SMTP or our simple to use Web API. Understand how best to utilize SendGrid.
Kickbox - Verify your email address lists with our drag and drop interface, or integrate into your app with our API. Prevent fake and bot account sign-ups by confirming your users are real humans with a real email address.
Sparkpost - Deliver your app and website emails on time and to the inbox. Trusted to send 25% of the world's non-spam email. Email delivery for companies big and small.
ZeroBounce - Removes invalid emails from your list to prevent email bounces from ruining your deliverability.
Postmark - Postmark is the easiest and most reliable way to be sure your important transactional emails get to the inbox. Simply & reliably parse recieved email to JSON for your webapp.