Email deliverability is one of those things most WordPress site owners never think about until something goes wrong — and by then, they’ve usually been losing emails for longer than they realize.

Password resets not arriving. Order confirmations going missing. Welcome emails landing in spam. And here’s the thing: most of your users aren’t going to tell you. They’ll just quietly go away.

The numbers tell the story pretty clearly. Default PHP mail — which is what a lot of cheap web hosts use by default — gets you roughly 64% deliverability. Switch to a proper dedicated SMTP service and that jumps to 96%+. That’s not a small difference. That’s a third of your emails disappearing into the void.

In this post I’m going to walk you through the main SMTP services worth knowing about, which ones I’d recommend, and which ones I’d steer clear of.

Start With FluentSMTP

Before we get into the services themselves, the plugin piece: I use and recommend FluentSMTP. It’s the bridge between your WordPress site and whatever SMTP service you connect to. Any email your site generates goes through FluentSMTP and out to your chosen provider.

One thing that makes it particularly useful is that you can connect multiple providers at the same time and route different types of email through different services. More on why that matters in a minute. And it’s free — no upsell nonsense.

Transactional vs. Marketing Email — Why It Matters

Before comparing services, you need to understand this distinction: transactional email (password resets, receipts, order confirmations, membership notifications) and marketing email (newsletters, promotions) should ideally travel on separate streams.

Why? Because whatever reputation your marketing emails build — good or bad — can bleed over and affect your transactional deliverability if they’re sharing the same pathway. You really don’t want a bulk promotional campaign to cause someone’s password reset to land in spam.

Some services handle both. Some specialize in one. And FluentSMTP lets you route them differently, which is exactly what you want.

Postmark — Best in Class

Postmark is my personal favorite right now, and it’s not particularly close. They’re consistently hitting 98-99% inbox placement — not just delivery rate, but actual inbox placement. That’s the number that actually matters.

They have separate streams for transactional and broadcast email, and delivery speed is impressive — around 1.2 seconds from the time the email hits Postmark to the time it shows up in the recipient’s inbox. They publish live delivery stats every five minutes, so you can actually see what’s happening.

The catch is cost. At $15 per 10,000 emails, it adds up fast — especially if you’re managing multiple sites or sending significant volume. For bulk marketing email in particular, Postmark can get expensive quickly. For transactional email though, it’s hard to argue against it.

Amazon SES — Cheapest, But…

Amazon SES is on the complete opposite end of the cost spectrum: 10 cents per 1,000 emails. Nothing else comes close on price.

I’ve used SES for my weekly newsletter for a while and the cost is genuinely trivial. But that’s where the good news ends.

Getting set up with Amazon SES is, and I say this without exaggeration, a torture session. If you’ve ever had to navigate AWS’s interface for anything, you know what I’m talking about. And the management experience is just as bad — if a subscriber ends up on your suppression list, you can barely see it and getting anyone off it is nearly impossible. So you just give up.

It’s a shared IP environment, so you’re subject to whatever your neighbors are doing. Deliverability is okay but not great. I still have some clients on it from the old days when setup was slightly less painful, but I don’t connect new clients to it anymore. The cost savings aren’t worth the headache.

SendGrid — Pass

SendGrid has been around forever but I can’t really recommend it anymore. Independent testing has shown delivery rates as low as 61% on shared IPs — which means you’d actually do better with Amazon SES on price AND deliverability.

There have been reports of account suspensions without warning, pricing changes with no notice, and since the acquisition, reviews have been all over the place. You can get decent results with a dedicated IP, but for most people using shared infrastructure, it’s just not worth it.

Mailgun — Trending the Wrong Way

Mailgun used to be a solid choice. It’s less so now. One report showed a 27.5% year-over-year drop in inbox placement in 2025 — and that’s inbox placement, not just delivery rate. There are also reports of problems specifically with Microsoft and Outlook addresses.

The WordPress plugin doesn’t surface failures well, so you’re essentially running blind. The trend is heading in the wrong direction, and I wouldn’t feel comfortable recommending it.

SMTP2GO — The Underrated Option

This one doesn’t get talked about enough. SMTP2GO is showing 95.5% deliverability in 2026 testing — that’s within striking distance of Postmark, and it’s a legitimately solid service.

The interface is clean, customer reviews are strong, and they have a free plan that covers up to 1,000 emails a month — which makes it easy to try before committing. Paid plans start at $15/10,000, so the pricing is similar to Postmark at scale, but that free tier gives it an edge for smaller senders or people who want to test it out first.

I haven’t used it as extensively as Postmark personally, but based on the numbers and what I’m seeing from others, it belongs in the same conversation.

ToSend — One to Watch

ToSend is the newest entry here, built by the same team behind FluentSMTP and FluentCRM. What makes it interesting is that it runs on Amazon SES infrastructure — so you get SES-level pricing (around 30 cents per 1,000) without having to deal with SES’s infamously painful setup and management interface.

I’ve been testing it with my weekly newsletter and the sending has been reliable. The real question is inbox placement over time, and we just don’t have enough data yet since it’s still relatively new. But the management layer they’re adding on top of SES infrastructure could potentially push deliverability meaningfully higher than raw SES.

It’s not fully public yet, but when it is, the cost-to-deliverability ratio could make it very compelling. Definitely one to keep an eye on.

The Smart Setup

If you want to optimize both deliverability and cost, here’s the approach I’d suggest:

Postmark for transactional. Receipts, password resets, membership notifications, order confirmations — anything where it really matters that the email arrives. Postmark is the best option available for this right now, full stop.

SMTP2GO or ToSend for bulk/marketing. Your newsletters and promotional emails go through a separate connection. This keeps your marketing activity from affecting your transactional reputation, and the lower per-email cost makes the volume much more manageable.

FluentSMTP lets you set this up exactly this way — two connections, routing based on email type. It’s the setup I use for my own sites and most of my Concierge clients.

Before You Do Anything Else

Go to mail-tester.com right now and check your current deliverability score. It’ll show you exactly where you stand and whether your emails are making it through. A lot of people are surprised by what they find.

If you’re not already using a dedicated SMTP service — or if you’re using one of the ones I said to avoid — this is worth sorting out. Your emails are either getting there or they’re not, and you probably don’t know which.