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SendX

Email software to send campaigns, build lists, and automate marketing

SendPost

Reach your customers' inboxes on time, every time with Email API + SMTP Relay

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Fix deliverability before it becomes a fire

SendPost gives you visibility into what mailbox providers are doing, control over how traffic flows, and an AI layer that spots risk early, before deliverability drops.

Talk to a SendPost expert
Fast, low-risk migration
Proven at 300M+ monthly volume
Trusted with high-risk senders
Works alongside your current MTA
Wk 1 96.8%

933.1K emails

Wk 2 97.9%

982K emails

Wk 3 97.7%

1.1M emails

Wk 4 97.2%

1.1M emails

Delivered
Opened
Soft Bounced
Hard Bounced
100% 75% 50% 25% 0%

Recognized by G2

SendPost is proud to be recognized as a leader in email deliverability and transactional email software.

Trusted by companies worldwide

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Built by ESP Operators

SendPost was built by the team of engineers and deliverability experts at SendX, which processes over 300 million emails/month. They've lived inside multi-tenant chaos, warmed IPs at 3 a.m., and debugged inbox drops with zero real signals to work with.

That’s why you’ll find things here you’ve never had before, but need to get full control and visibility into your email deliverability.

"Most MTAs hide the signals that matter. SendPost surfaces them. You see IP health, domain reputation, ISP responses— all the things deliverability teams usually have to guess at."

LoriBeth Blair

LoriBeth Blair

Email Deliverability Consultant

The full AI-driven toolkit for ESPs to send emails reliably

Real visibility into your entire mail flow

Most MTAs abstract this away. SendPost gives you the full picture so you can actually act on it.

Live ISP response data (Gmail, Yahoo, Microsoft, etc.)
IP + domain reputation signals
Sender-level performance and risk surfacing
Account, subaccount, and group-level stats
Real-time dashboards for multi-tenant sending
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AI alerts that catch problems before they hit customers

SendPost’s Deliverability AI watches sending patterns and mailbox provider responses in real time, compares them against historical baselines, and flags issues the moment behavior starts to drift.

Smart alerts for soft bounces, deferrals, and reputation shifts
Root-cause signals tied to specific senders, domains, or IPs
Early-warning behavior modeling to detect risky patterns
Alerts on Slack or email (not buried in logs)
Learn more

ESP-grade control over sending

Stop relying on fixed, one-size-fits-all sending rules. Shape traffic by ISP, adjust queues in real time, and keep risky senders from dragging down your reputation.

Per-ISP throttling controls
Queue management for every sender
Intelligent routing based on provider behavior
Dedicated and shared IP pool management
Fine-grained control over subaccounts and groups
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Automation that saves hours of manual work

You could take a longer lunch break because everything you do manually will be handled automatically by SendPost

Auto IP warmup for new senders
Customer warmup plans that adapt to behavior
AI-powered throttling and delivery logic
Automatic backoff and retry logic
Workflow automation with Slack commands
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Infrastructure that fits into what you already have

You don’t need to overhaul your stack. You add SendPost today, and gain visibility. Route traffic when you’re ready.

API and SMTP relay integration without changes to your app
Webhooks for opens, clicks, bounces, and complaints
Event logs with full traceability
SDKs in 14+ languages
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The deliverability CRM built for ESPs

A central place to track issues, connect the dots, and stop repeated failures.

Incident tracking with prioritization
Root-cause mapping to senders, IPs, or domains
Reputation history across all customers
Knowledge base for recurring patterns
Team workflows for resolving issues faster
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What customers are saying...

“I’ve worked with SendGrid, Mailgun, SparkPost — none of them come close to this level of visibility that SendPost offers. It finally gives email deliverability professionals the data we’ve been begging for.”

LoriBeth Blair

Email Deliverability Consultant

See SendPost In Action

How an ESP operates when it's powered by SendPost

As monthly volume grew from 100M to 300M+ emails, SendX maintained 95–98% delivery rates and maintained its deliverability team size at only 3 people. All because it moved from legacy sending engines to an AI-driven sending engine — SendPost.

95–98%

inbox placement even as volume scaled from 100M to 300M emails per month

3x

more sending capacity without adding headcount

2–5 hours

saved per week per engineer by removing manual warmups

30–90 min

Issues caught earlier with real-time ISP signals

60%

fewer customer escalations as risky senders surface early

100%

visibility into IPs + domains vs 10–20% most MTAs expose

Talk to a SendPost expert

If you want your Sunday to stay yours, choose SendPost

Here's what changes when you stop guessing, stop reacting, and stop getting blindsided by issues your MTA never warned you about.

Before

You rely on a black-box sending engine that hides IP and domain health

After

You see live IP reputation, domain health, and sender behavior in real time

Before

You have no way to see which senders are dragging your reputation down

After

Risky senders surface automatically before they damage your pools

Before

Routing decisions are fixed and can't be shaped per ISP

After

Routing adapts to each ISP and each sender profile

Before

Logs come as raw webhooks with no interpretation

After

SMTP signals are translated into clear insights you can act on

Before

You can't track multi-tenant risk or behavior anomalies

After

Multi-tenant reputation and blacklist monitoring happen continuously

Before

Issues show up as client complaints before you notice them. Legacy tools shrug. Nothing warns you.

After

AI-driven alerts fire long before customers ever notice issues

Save My Weekend

Take on more customers without paying the price for It

You don’t run an ESP full of identical, spotless senders. No one does.

Some customers are polished, some are messy, and most are somewhere in between. That shouldn’t force you to turn business away or fear they'll get you banned by your sending engine. 

That's why SendPost is built to handle the variation that comes with running an ESP.

We power email for ESPs across every legal industry from SaaS and marketplaces to finance, healthcare, and beyond.

It's true. We’re not 100 years old.

SendPost wasn’t built decades ago, and we don't have a legacy to show you. 

But new doesn’t mean risky.

You still get a modern foundation that fits today’s reality, without giving up the reliability you expect from established infrastructure.

Full privacy and data containment

99.99% uptime

Strict IP, domain, and sender isolation

Clear audit trails for every decision

Safe, low-risk adoption path

Plus, we didn’t inherit the blind spots, black boxes, and hard limits that legacy sending engines still ship with.

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The only thing left is to see SendPost in action

Invest 30 minutes, and you’ll see the deliverability signals you’ve been missing, and exactly why your current platform hides them from you.

Give me the Tour →

Frequently asked questions

Everything you need to know about SendPost and transactional email delivery

What is SendPost?

SendPost is a powerful sending engine, email delivery service, email deliverability platform and cloud MTA built for deliverability specialists, developers and businesses of all sizes. We provide a highly reliable Email API and SMTP Relay service with advanced analytics layer with MTA level controls designed to send your crucial transactional and marketing emails at scale, with a strong focus on ensuring they reach the inbox every time.

Can I integrate SendPost with my own application?

Absolutely. SendPost is designed for developers. We offer a robust Email API, SMTP relay service, and SDKs in over 14 programming languages. Additionally, our Email Webhooks allow you to receive real-time event data directly in your application for seamless integration and workflow automation.

Do you offer a free plan or trial?

No, at the moment we require a demo and up front financial commitment to use SendPost.

How does SendPost's pricing compare for high-volume sending?

SendPost is significantly more cost-effective for transactional and high-volume email at scale. Our pay-as-you-go pricing is tied directly to your usage, not your subscriber count. This means you don't overpay for storing contacts and only get charged for the emails you actually send, making it a more economical and scalable solution for applications.

What kind of analytics and reporting do you provide?

SendPost provides a powerful dashboard with real-time analytics to track your email performance. You can monitor key metrics like delivery rates, bounces, opens, clicks, and unsubscribes. These detailed insights help you optimize your email program and quickly diagnose any potential deliverability issues.

Still have questions? We're here to help.

Visit Help Center