Omnivery
Mailgun
SendGrid Email API
Sparkpost
Postmark
Mailjet
Mandrill
Amazon SES
InboxStack
GlockApps
Email Testing By Inbox Pirates
Validity LLC
MxToolBox
Folderly
HetrixTools
Inbox AI
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).
InboxStack is an email deliverability intelligence platform built for teams who need to know why their emails aren't reaching the inbox โ not just that they aren't. At its core is Brain, a proprietary causal AI engine trained on a 22-year deliverability knowledge base, which correlates signals across your ESP, DNS authentication records (SPF, DKIM, DMARC), Google Postmaster Tools, Microsoft SNDS, and 50+ blocklists to pinpoint root causes instead of surfacing raw metrics.
Most deliverability tools stop at monitoring: they show you a drop in inbox placement or a blocklist hit and leave you to investigate. InboxStack goes further, tracing the actual causal chain โ a DKIM misalignment, a reputation dip on a specific sending IP, a content trigger โ so you can fix the real problem instead of guessing.
Setup takes minutes with no migration required: forward your email headers for an instant DNS/authentication audit, or connect your existing ESP and Postmaster accounts for ongoing monitoring. Optional seed testing gives you real inbox-vs-spam placement data across major providers.
Built for agencies managing multiple client domains and growing companies who've outgrown basic authentication checkers, InboxStack turns deliverability from a black box into a diagnosable, fixable system.
Omnivery InboxStackOmnivery'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.
As an email marketing agency we've been using Omnivery for our clients for several years now and their proactive support never case to amaze us. We're sending through Omnivery apprx. 250 mio. emails / year. Excellent service in every way, highly recommended
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.
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